Add support for Python 3.8.7

Closes @W-7791264@.

.git2gus/config.json

@@ -0,0 +1,6 @@
+{
+  "productTag": "a1aB0000000MR0RIAW",
+  "issueTypeLabels": { "gus: story": "USER STORY", "gus: bug": "BUG P3" },
+  "defaultBuild": "Heroku Unscheduled",
+  "statusWhenClosed": "CLOSED"
+}

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @heroku/languages

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,8 @@
+<!-- Hi and welcome to the Heroku Python buildpack repository!
+
+If you meant to open a PR against a fork instead of upstream, please adjust the base branch:
+https://help.github.com/articles/changing-the-base-branch-of-a-pull-request/
+
+Otherwise thank you in advance for your Pull Request - just remember to
+include as much information as possible to help the reviewers :-)
+-->

.github/dependabot.yml

@@ -0,0 +1,15 @@
+version: 2
+updates:
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    labels:
+      - "c: dependencies"
+
+  - package-ecosystem: "bundler"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    labels:
+      - "c: dependencies"

.github/workflows/check_changelog.yml

@@ -0,0 +1,17 @@
+name: Check Changelog
+
+on:
+  pull_request:
+    types: [opened, reopened, edited, synchronize]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    if: |
+      !contains(github.event.pull_request.body, '[skip changelog]') &&
+      !contains(github.event.pull_request.body, '[changelog skip]') &&
+      !contains(github.event.pull_request.body, '[skip ci]')
+    steps:
+      - uses: actions/checkout@v1
+      - name: Check that CHANGELOG is touched
+        run: git diff remotes/origin/${{ github.base_ref }} --name-only | grep CHANGELOG.md

.gitignore

@@ -3,3 +3,12 @@ site
 .DS_Store
 
 /.envrc
+repos/*
+
+#Venv
+buildpack/*
+
+builds/dockerenv.staging*
+builds/dockerenv.production
+
+test/scratch

.travis.yml

@@ -1,23 +1,41 @@
-language: bash
+language: minimal
-dist: trusty
+dist: focal
+branches:
+  only:
+  - main
+
+script:
+  - make test STACK="${STACK}" TEST_CMD="${TEST_CMD}"
+
 jobs:
   include:
-    - stage: "Bash linting (shellcheck)"
+  - name: Bash linting (shellcheck)
-      sudo: false
-      addons:
-        apt:
-          sources:
-          - debian-sid    # Grab shellcheck from the Debian repo (o_O)
-          packages:
-          - shellcheck
     script: make check
+  - name: Hatchet integration tests
+    if: env(HEROKU_API_USER) IS present AND env(HEROKU_API_KEY) IS present
+    language: ruby
+    rvm:
+      - 2.7
+    before_script:
+      - bundle exec hatchet ci:setup
+    script:
+      - PARALLEL_SPLIT_TEST_PROCESSES=11 bundle exec parallel_split_test spec/hatchet/
 
-    - stage: "Stack Tests"
+env:
-      services: docker
+  jobs:
-      env: STACK=heroku-16
+    - STACK=heroku-16 TEST_CMD=test/run-deps
-      script: ./tests.sh
+    - STACK=heroku-16 TEST_CMD=test/run-versions
+    - STACK=heroku-16 TEST_CMD=test/run-features
 
-    - stage: "Stack Tests"
+    - STACK=heroku-18 TEST_CMD=test/run-deps
-      services: docker
+    - STACK=heroku-18 TEST_CMD=test/run-versions
-      env: STACK=cedar-14
+    - STACK=heroku-18 TEST_CMD=test/run-features
-      script: ./tests.sh
+
+    - STACK=heroku-20 TEST_CMD=test/run-deps
+    - STACK=heroku-20 TEST_CMD=test/run-versions
+    - STACK=heroku-20 TEST_CMD=test/run-features
+  global:
+    - HATCHET_RETRIES=3
+    - IS_RUNNING_ON_CI=true
+    - HATCHET_APP_LIMIT=80
+    - HATCHET_DEPLOY_STRATEGY=git

CHANGELOG.md

@@ -1,69 +1,409 @@
 # Python Buildpack Changelog
 
-# 116
+## Unreleased
+
+- Python 3.8.7 is now available (CPython) (#1122).
+
+## v186 (2020-11-18)
+
+- Update the `BUILD_WITH_GEO_LIBRARIES` error message (#1121).
+- Switch NLTK feature detection away from `sp-grep` (#1119).
+- Switch Django collectstatic feature detection away from `sp-grep` (#1119).
+- Remove vendored `sp-grep` script (#1119).
+- Remove vendored `pip-diff` script (#1118).
+- Remove vendored `pip-grep` script (#1116).
+
+## v185 (2020-11-12)
+
+- Error if the unsupported `BUILD_WITH_GEO_LIBRARIES` env var is set (#1115).
+- Remove deprecated GDAL/GEOS/PROJ support (#1113).
+- Remove vendored `jq` binary (#1112).
+- Remove redundant Mercurial install step (#1111).
+- Remove support for the Cedar-14 stack (#1110).
+
+## v184 (2020-10-21)
+
+- Vendor buildpack-stdlib instead of fetching from S3 (#1100).
+- Fix metric names for metrics emitted within `sub_env` (#1099).
+
+## v183 (2020-10-12)
+
+- Add support for Heroku-20 (#968).
+
+## v182 (2020-10-06)
+
+- Python 3.9.0 is now available (CPython) (#1090).
+- Migrate from the `lang-python` S3 bucket to `heroku-buildpack-python` (#1089).
+- Remove `vendor/shunit2` (#1086).
+- Replace `BUILDPACK_VENDOR_URL` and `USE_STAGING_BINARIES` with `BUILDPACK_S3_BASE_URL` (#1085).
+
+## v181 (2020-09-29)
+
+- PyPy 2.7 and 3.6, version 7.3.2 are now available (Note: PyPy support is in beta) (#1081).
+
+## v180 (2020-09-24)
+
+- Python 3.8.6 is now available (CPython) (#1072).
+
+## v179 (2020-09-23)
+
+- Remove duplicate pipenv metric event (#1070).
+- Emit metrics for how the Python version was chosen for an app (#1069).
+- Emit Python version metric events for all builds, not just clean installs (#1066).
+
+## v178 (2020-09-07)
+
+- Python 3.5.10 is now available (CPython) (#1062).
+
+## v177 (2020-08-18)
+
+- Python 3.6.12 and 3.7.9 are now available (CPython) (#1054).
+- The default Python version for new apps is now 3.6.12 (previously 3.6.11) (#1054).
+
+## v176 (2020-08-12)
+
+- Rebuild the Python 3.4.10 archives with the correct version of Python (#1048).
+- Fix the security update version check message for apps using PyPy (#1040).
+- Remove `vendor/test-utils` (#1043).
+
+## v175 (2020-08-05)
+
+- Update pip from 20.0.2 to 20.1.1 for Python 2.7 and Python 3.5+ (#1030).
+- Update setuptools from 39.0.1 to: (#1024)
+  - 44.1.1 for Python 2.7
+  - 43.0.0 for Python 3.4
+  - 47.1.1 for Python 3.5+
+- Switch the `heroku-buildpack-python` repository default branch from `master` to `main` (#1029).
+
+## v174 (2020-07-30)
+
+- For repeat builds, also manage the installed versions of setuptools/wheel, rather than just that of pip (#1007).
+- Install an explicit version of wheel rather than the latest release at the time (#1007).
+- Output the installed version of pip, setuptools and wheel in the build log (#1007).
+- Errors installing pip/setuptools/wheel are now displayed in the build output and fail the build early (#1007).
+- Install pip using itself rather than `get-pip.py` (#1007).
+- Disable pip's version check + cache when installing pip/setuptools/wheel (#1007).
+- Install setuptools from PyPI rather than a vendored copy (#1007).
+- Reduce the number of environment variables exposed to `bin/{pre,post}_compile` and other subprocesses (#1011).
+
+## v173 (2020-07-21)
+
+- Python 3.8.5 is now available (CPython).
+
+## v172 (2020-07-17)
+
+- Python 3.8.4 is now available (CPython).
+
+## v171 (2020-07-07)
+
+- Python 3.6.11 and 3.7.8 are now available (CPython).
+
+## v170 (2020-05-19)
+
+- Python 2.7.18, 3.5.9, 3.7.7 and 3.8.3 are now available (CPython).
+- PyPy 2.7 and 3.6, version 7.3.1 are now available (Note: PyPy support is in beta).
+- Docs: Fix explanation of runtime.txt generation when using pipenv.
+- Bugfix: Correctly detect Python version when using a `python_version` of `3.8` in `Pipfile.lock`.
+
+## v169 (2020-04-22)
+
+- Add a Hatchet test for python 3.8.2
+- Set Code Owners to @heroku/langauges
+- Bugfix: Caching on subsequent redeploys
+- Update tests to support latest version of Python
+
+## v168 (2020-04-06)
+
+- Doc: Update Readme with version numbers
+- update Code Owners to include the Heroku Buildpack Maintainers team
+- Deprecation warning: `BUILD_WITH_GEO_LIBRARIES` is now deprecated. See warning for details.
+- Clean up build log output
+- Update Python versions in README to match docs
+- Django version detection fixed, link updated
+
+## v167 (2020-03-26)
+
+- Add failcase for cache busting
+- Bugfix: Clearing pip dependencies
+
+## v166 (2020-03-05)
+
+- Correct ftp to https in vendored file
+- Warn for Django 1.11 approaching EOL, provide link to roadmap
+
+## v165 (2020-02-27)
+
+- Python 3.8.2 now available.
+
+## v164 (2020-02-20)
+
+- Update requirements.txt builds to use Pip 20.0.2
+- Download get-pip.py to tmpdir instead of root dir
+
+## v163 (2019-12-23)
+
+- New pythons released:
+  Python 3.8.1, 3.7.6, 3.6.10 (CPython)
+  Beta Release: Pypy 2.7 and 3.6, version 7.2.0
+
+## v162 (2019-12-06)
+
+- Bug fix: fragile sqlite3 install
+
+## v161 (2019-12-2)
+
+- Bug fix: Sqlite3 version bump
+
+## v160 (2019-10-23)
+
+- Bugfix: Pipenv no longer installs twice in CI
+
+## v159 (2019-10-22)
+
+- Python 2.7.17 now available on Heroku 18 and 16.
+
+## v158 (2019-10-21)
+
+- Python 3.7.5 and 3.8.0 now available on Heroku 18 and 16.
+- Add support for Python 3.8 branch
+- Sqlite3 Update:
+  - Test Improvements
+- Add support for staging binary testing
+
+## v157 (2019-09-18)
+
+- Typo fixes
+
+## v156 (2019-09-12)
+
+- Python 3.6.9 and 3.7.4 now available.
+
+- Move get-pip utility to S3
+- Build utility and documentation updates
+- Bump Hatchet tests to point at new default python version.
+
+## v155 (2019-08-22)
+
+add docs and make target for heroku-18 bob builds
+
+## v154 (2019-07-17)
+
+Fix python 3.5.7 formula actually building 3.7.2
+
+## v153 (2019-06-21)
+
+Hotfix for broken heroku-16 deploys
+
+## v152 (2019-04-04)
+
+Python 3.7.3 now available.
+
+## v151 (2019-03-21)
+
+Python 3.5.7 and 3.4.10 now available on all Heroku stacks.
+
+## v150 (2019-03-13)
+
+Python 2.7.16 now available on all Heroku stacks.
+
+## v149 (2019-03-04)
+
+Hotfix for broken Cedar 14 deploys
+
+## v148 (2019-02-21)
+
+No user facing changes, improving internal metrics
+
+## v147 (2019-02-07)
+
+Python 3.7.2 and 3.6.8 now available on all Heroku stacks.
+
+## v146 (2018-11-11)
+
+Python 3.7.1, 3.6.7, 3.5.6 and 3.4.9 now available on all Heroku stacks.
+
+## v145 (2018-11-08)
+
+Testing and tooling expanded to better support new runtimes
+
+## v144 (2018-10-10)
+
+Switch to cautious upgrade for Pipenv install to ensure the pinned pip version
+is used with Pipenv
+
+## v143 (2018-10-09)
+
+Add support for detecting `SLUGIFY_USES_TEXT_UNIDECODE`, which is required to
+install Apache Airflow version 1.10 or higher.
+
+## v142 (2018-10-08)
+
+Improvements to Python install messaging
+
+## v139, 140, 141
+
+No user-facing changes, documenting for version clarity
+
+## v138 (2018-08-01)
+
+Use stack image SQLite3 instead of vendoring
+
+## v137 (2018-07-17)
+
+Prevent 3.7.0 from appearing as unsupported in buildpack messaging.
+
+## v136 (2018-06-28)
+
+Upgrade to 3.6.6 and support 3.7.0 on all runtimes.
+
+## v135 (2018-05-29)
+
+Upgrade Pipenv to v2018.5.18.
+
+## v134 (2018-05-02)
+
+Default to 3.6.5, bugfixes.
+
+## v133
+
+Fixes for Pip 10 release.
+
+## v132
+
+Improve pip installation, with the release of v9.0.2.
+
+## v131
+
+Fix bug with pip.
+
+## v130
+
+Better upgrade strategy for pip.
+
+## v129
+
+Don't upgrade pip (from v128).
+
+## v128
+
+Upgrade pip, pin to Pipenv v11.8.2.
+
+## v127
+
+Pin to Pipenv v11.7.1.
+
+## v126
+
+Bugfixes.
+
+## v125
+
+Bugfixes.
+
+## v124
+
+Update buildpack to automatically install `[dev-packages]` during Heroku CI Pipenv builds.
+
+- Skip installs if Pipfile.lock hasn't changed, and uninstall stale dependencies with Pipenv.
+- Set `PYTHONPATH` during collectstatic runs.
+- No longer warn if there is no `Procfile`.
+- Update Pipenv's "3.6" runtime specifier to point to "3.6.4".
+
+## v123
+
+Update gunicorn `init.d` script to allow overrides.
+
+## v122
+
+Update default Python to v3.6.4.
+
+## v121
+
+Update default Python to v3.6.3.
+
+## v120
+
+Use `$ pipenv --deploy`.
+
+## v119
+
+Improvements to Pipenv support, warning on unsupported Python versions.
+
+- We now warn when a user is not using latest 2.x or 3.x Python.
+- Heroku now supports `[requires]` `python_full_version` in addition to `python_version`.
+
+## v118
+
+Improvements to Pipenv support.
+
+## v117
+
+Bug fix.
+
+## v116
 
 Vendoring improvements.
 
 - Geos libraries should work on Heroku-16 now.
 - The libffi/libmemcached vendoring step is now skipped on Heroku-16 (since they are installed in the base image).
 
-# 115
+## v115
 
 Revert a pull request.
 
 - No longer using `sub_env` for `pip install` step.
 
-# 114
+## v114
 
 - Bugfixes.
 
 Blacklisting `PYTHONHOME` and `PYTHONPATH` for older apps. Upgrades to nltk support.
 
-# 113
+## v113
 
 Updates to Pipenv support.
 
-# 112
+## v112
 
 Bugfix.
 
 - Fixed grep output bug.
 
-# 111
+## v111
 
 Linting, bugfixes.
 
-# 110
+## v110
 
 Update default Python to 3.6.2.
 
-# 109
+## v109
 
 Update Default Python to 3.6.1, bugfixes.
 
 - Fixed automatic pip uninstall of dependencies removed from requirements.txt.
 
-# 108
+## v108
 
 Fix output for collectstatic step.
 
-# 107
+## v107
 
 Bugfix for C dependency installation.
 
-# 106
+## v106
 
- Don't install packages that could mess up packaging.
+Don't install packages that could mess up packaging.
 
  - The Python buildpack will automatically remove `six`, `pyparsing`, `appdirs`,
    `setuptools`, and `distribute` from a `requirements.txt` file now, as these
    packages are provided by the Python buildpack.
 
- # 105
+## v105
 
- Improvements to output messaging.
+Improvements to output messaging.
 
-# 104
+## v104
 
 General improvements.
 
@@ -73,52 +413,52 @@ General improvements.
 
 [395]: https://github.com/heroku/heroku-buildpack-python/pull/395
 
-## 103
+## v103
 
 Bug fixes and improvements.
 
 - Fix for Pipenv.
 - Fix for Heroku CI.
-- Improve handling of WEB_CONCURRENCY when using multiple buildpacks.
+- Improve handling of `WEB_CONCURRENCY` when using multiple buildpacks.
-- Adjust environment variables set during the build to more closely match those in the dyno environment (DYNO is now available, STACK is not).
+- Adjust environment variables set during the build to more closely match those in the dyno environment (`DYNO` is now available, `STACK` is not).
 - Restore the build cache prior to running bin/pre_compile.
 
-## 102
+## v102
 
 Buildpack code cleanup.
 
 - Improved messaging around NLTK.
 
-## 101
+## v101
 
 Updated setuptools installation method.
 
 - Improved pipenv support.
 
-## 100
+## v100
 
 Preliminary pipenv support.
 
-## 99
+## v99
 
 Cleanup.
 
-## 98
+## v98
 
 Official NLTK support and other improvements.
 
 - Support for `nltk.txt` file for declaring corpora to be downloaded.
-- Leading zeros for auto-set WEB_CONCURRENCY.
+- Leading zeros for auto-set `WEB_CONCURRENCY`.
 
-## 97
+## v97
 
 Improved egg-link functionality.
 
-## 96
+## v96
 
 Bugfix.
 
-## 95
+## v95
 
 Improved output support.
 
@@ -154,7 +494,7 @@ Fixed bug with editable pip installations.
 
 Updated default Python 2.7.13.
 
-- Python 2.7.13 uses UCS-4 build, more compatibile with linux wheels.
+- Python 2.7.13 uses UCS-4 build, more compatible with linux wheels.
 - Updated setuptools to v32.1.0.
 
 ## v86
@@ -180,7 +520,7 @@ Support for Heroku CI.
 
 ## v82 (2016-08-22)
 
-Update to library detection mechnisms (pip-pop).
+Update to library detection mechanisms (pip-pop).
 
 - Updated setuptools to v25.5.0
 
@@ -254,7 +594,7 @@ Revert to v66.
 
 ## v68 (2015-10-12)
 
-Fixed .heroku/venv error with modern apps.
+Fixed `.heroku/venv` error with modern apps.
 
 ## v67 (2015-10-12)
 
@@ -279,7 +619,6 @@ Updated Pip and Setuptools.
 - Setuptools updated to v18.3.2
 - Pip updated to v7.1.2
 
-
 ## v62 (2015-08-07)
 
 Updated Pip and Setuptools.

Dockerfile

@@ -1,13 +0,0 @@
-FROM heroku/heroku:16-build
-
-WORKDIR /app
-ENV WORKSPACE_DIR="/app/builds" \
-    S3_BUCKET="lang-python" \
-    S3_PREFIX="heroku-16/"
-
-RUN apt-get update && apt-get install -y python-pip && rm -rf /var/lib/apt/lists/*
-
-COPY requirements.txt /app/
-RUN pip install --disable-pip-version-check --no-cache-dir -r /app/requirements.txt
-
-COPY . /app

Gemfile

@@ -0,0 +1,8 @@
+source "https://rubygems.org"
+
+gem "rspec"
+gem "heroku_hatchet"
+gem "rspec-retry"
+gem "rake"
+gem "parallel_split_test"
+

Gemfile.lock

@@ -0,0 +1,60 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    diff-lcs (1.4.4)
+    erubis (2.7.0)
+    excon (0.78.0)
+    heroics (0.1.1)
+      erubis (~> 2.0)
+      excon
+      moneta
+      multi_json (>= 1.9.2)
+    heroku_hatchet (7.3.3)
+      excon (~> 0)
+      platform-api (~> 3)
+      rrrretry (~> 1)
+      thor (~> 1)
+      threaded (~> 0)
+    moneta (1.0.0)
+    multi_json (1.15.0)
+    parallel (1.19.2)
+    parallel_split_test (0.8.0)
+      parallel (>= 0.5.13)
+      rspec (>= 3.1.0)
+    platform-api (3.0.0)
+      heroics (~> 0.1.1)
+      moneta (~> 1.0.0)
+      rate_throttle_client (~> 0.1.0)
+    rake (13.0.1)
+    rate_throttle_client (0.1.2)
+    rrrretry (1.0.0)
+    rspec (3.10.0)
+      rspec-core (~> 3.10.0)
+      rspec-expectations (~> 3.10.0)
+      rspec-mocks (~> 3.10.0)
+    rspec-core (3.10.0)
+      rspec-support (~> 3.10.0)
+    rspec-expectations (3.10.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-mocks (3.10.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-retry (0.6.2)
+      rspec-core (> 3.3)
+    rspec-support (3.10.0)
+    thor (1.0.1)
+    threaded (0.0.4)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  heroku_hatchet
+  parallel_split_test
+  rake
+  rspec
+  rspec-retry
+
+BUNDLED WITH
+   2.1.4

Makefile

@@ -1,37 +1,61 @@
 # These targets are not files
-.PHONY: tests
+.PHONY: check test compile builder-image buildenv deploy-runtimes tools
 
-test: test-heroku-16
+STACK ?= heroku-18
+STACKS ?= heroku-16 heroku-18 heroku-20
+TEST_CMD ?= test/run-versions && test/run-features && test/run-deps
+FIXTURE ?= test/fixtures/requirements-standard
+ENV_FILE ?= builds/dockerenv.default
+BUILDER_IMAGE_PREFIX := heroku-python-build
+
+# Converts a stack name of `heroku-NN` to its build Docker image tag of `heroku/heroku:NN-build`.
+STACK_IMAGE_TAG := heroku/$(subst -,:,$(STACK))-build
 
 check:
-	@shellcheck -x bin/compile bin/detect bin/release bin/test-compile bin/utils bin/warnings
+	@shellcheck -x bin/compile bin/detect bin/release bin/test-compile bin/utils bin/warnings bin/default_pythons
-	@shellcheck -x bin/steps/collectstatic bin/steps/cryptography bin/steps/eggpath-fix  bin/steps/eggpath-fix2 bin/steps/gdal bin/steps/geo-libs bin/steps/mercurial bin/steps/nltk bin/steps/pip-install bin/steps/pip-uninstall bin/steps/pipenv bin/steps/pipenv-python-version bin/steps/pylibmc bin/steps/python
+	@shellcheck -x bin/steps/collectstatic bin/steps/eggpath-fix  bin/steps/eggpath-fix2 bin/steps/nltk bin/steps/pip-install bin/steps/pipenv bin/steps/pipenv-python-version bin/steps/python
 	@shellcheck -x bin/steps/hooks/*
 
-test-cedar-14:
+test:
-	@echo "Running tests in docker (cedar-14)..."
+	@echo "Running tests using: STACK=$(STACK) TEST_CMD='$(TEST_CMD)'"
-	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=cedar-14" heroku/cedar:14 bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
-	@echo ""
-
-test-heroku-16:
-	@echo "Running tests in docker (heroku-16)..."
-	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=heroku-16" heroku/heroku:16-build bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
-	@echo ""
-
-buildenv-heroku-16:
-	@echo "Creating build environment (heroku-16)..."
 	@echo
-	@docker build --pull -t python-buildenv-heroku-16 .
+	@docker run --rm -it -v $(PWD):/buildpack:ro -e "STACK=$(STACK)" "$(STACK_IMAGE_TAG)" bash -c 'cp -r /buildpack /buildpack_test && cd /buildpack_test && $(TEST_CMD)'
+	@echo
+
+compile:
+	@echo "Running compile using: STACK=$(STACK) FIXTURE=$(FIXTURE)"
+	@echo
+	@docker run --rm -it -v $(PWD):/src:ro -e "STACK=$(STACK)" -w /buildpack "$(STACK_IMAGE_TAG)" \
+		bash -c 'cp -r /src/{bin,vendor} /buildpack && cp -r /src/$(FIXTURE) /build && mkdir /cache /env && bin/compile /build /cache /env'
+	@echo
+
+builder-image:
+	@echo "Generating binary builder image for $(STACK)..."
+	@echo
+	@docker build --pull -f builds/$(STACK).Dockerfile -t "$(BUILDER_IMAGE_PREFIX)-$(STACK)" .
+	@echo
+
+buildenv: builder-image
+	@echo "Starting build environment for $(STACK)..."
 	@echo
 	@echo "Usage..."
 	@echo
-	@echo "  $$ export AWS_ACCESS_KEY_ID=foo AWS_SECRET_ACCESS_KEY=bar  # Optional unless deploying"
+	@echo "  $$ bob build runtimes/python-X.Y.Z"
-	@echo "  $$ bob build runtimes/python-2.7.13"
-	@echo "  $$ bob deploy runtimes/python-2.7.13"
 	@echo
-	@docker run -it --rm python-buildenv-heroku-16
+	@docker run --rm -it --env-file="$(ENV_FILE)" -v $(PWD)/builds:/app/builds "$(BUILDER_IMAGE_PREFIX)-$(STACK)" bash
 
-tools:
+deploy-runtimes:
-	git clone https://github.com/kennethreitz/pip-pop.git
+ifndef RUNTIMES
-	mv pip-pop/bin/* vendor/pip-pop/
+	$(error No runtimes specified! Use: "make deploy-runtimes RUNTIMES='python-X.Y.Z ...' [STACKS='heroku-18 ...'] [ENV_FILE=...]")
-	rm -fr pip-pop
+endif
+	@echo "Using: RUNTIMES='$(RUNTIMES)' STACKS='$(STACKS)' ENV_FILE='$(ENV_FILE)'"
+	@echo
+	@set -eu; for stack in $(STACKS); do \
+		$(MAKE) builder-image STACK=$${stack}; \
+		for runtime in $(RUNTIMES); do \
+			echo "Generating/deploying $${runtime} for $${stack}..."; \
+			echo; \
+			docker run --rm -it --env-file="$(ENV_FILE)" "$(BUILDER_IMAGE_PREFIX)-$${stack}" bob deploy "runtimes/$${runtime}"; \
+			echo; \
+		done; \
+	done

NOTICE

@@ -1,27 +1,5 @@
 This buildpack includes some vendorized packages to ease installation.
 
-jq license
-----------
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-
-
 shunit2 license
 ---------------
 
@@ -85,53 +63,3 @@ The Free Software Foundation may publish revised and/or new versions of the GNU
 Each version is given a distinguishing version number. If the Library as you received it specifies that a certain numbered version of the GNU Lesser General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that published version or of any later version published by the Free Software Foundation. If the Library as you received it does not specify a version number of the GNU Lesser General Public License, you may choose any version of the GNU Lesser General Public License ever published by the Free Software Foundation.
 
 If the Library as you received it specifies that a proxy can decide whether future versions of the GNU Lesser General Public License shall apply, that proxy's public statement of acceptance of any version is permanent authorization for you to choose that version for the Library.
-
-get-pip.py license
-------------------
-
-Copyright (c) 2008-2016 The pip developers (see AUTHORS.txt file)
-
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
-
-pip-pop license
----------------
-
-The MIT License (MIT)
-
-Copyright (c) 2014 Kenneth Reitz.
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.

README.md

@@ -2,38 +2,57 @@
 
 # Heroku Buildpack: Python
 
-[![Build Status](https://travis-ci.org/heroku/heroku-buildpack-python.svg?branch=master)](https://travis-ci.org/heroku/heroku-buildpack-python)
+[![Build Status](https://travis-ci.com/heroku/heroku-buildpack-python.svg?branch=main)](https://travis-ci.com/heroku/heroku-buildpack-python)
 
-This is the official [Heroku buildpack](https://devcenter.heroku.com/articles/buildpacks) for Python apps, powered by [Pipenv](http://docs.pipenv.org/en/latest/), [pip](https://pip.pypa.io/) and other excellent software.
+This is the official [Heroku buildpack](https://devcenter.heroku.com/articles/buildpacks) for Python apps.
 
-Recommended web frameworks include **Django** and **Flask**. The recommended webserver is **Gunicorn**. There are no restrictions around what software can be used (as long as it's pip-installable). Web processes must bind to `$PORT`, and only the HTTP protocol is permitted for incoming connections.
+Recommended web frameworks include **Django** and **Flask**, among others. The recommended webserver is **Gunicorn**. There are no restrictions around what software can be used (as long as it's pip-installable). Web processes must bind to `$PORT`, and only the HTTP protocol is permitted for incoming connections.
 
-Some Python packages with obscure C dependencies are [not compatible](https://devcenter.heroku.com/articles/python-c-deps).
+Python packages with C dependencies that are not [available on the stack image](https://devcenter.heroku.com/articles/stack-packages) are generally not supported, unless `manylinux` wheels are provided by the package maintainers (common). For recommended solutions, check out [this article](https://devcenter.heroku.com/articles/python-c-deps) for more information.
 
 See it in Action
 ----------------
+```
+$ ls
+my-application		requirements.txt	runtime.txt
 
-Deploying a Python application couldn't be easier:
+$ git push heroku main
+Counting objects: 4, done.
+Delta compression using up to 8 threads.
+Compressing objects: 100% (2/2), done.
+Writing objects: 100% (4/4), 276 bytes | 276.00 KiB/s, done.
+Total 4 (delta 0), reused 0 (delta 0)
+remote: Compressing source files... done.
+remote: Building source:
+remote:
+remote: -----> Python app detected
+remote: -----> Installing python
+remote: -----> Installing pip
+remote: -----> Installing SQLite3
+remote: -----> Installing requirements with pip
+remote:        Collecting flask (from -r /tmp/build_c2c067ef79ff14c9bf1aed6796f9ed1f/requirements.txt (line 1))
+remote:          Downloading ...
+remote:        Installing collected packages: Werkzeug, click, MarkupSafe, Jinja2, itsdangerous, flask
+remote:        Successfully installed Jinja2-2.10 MarkupSafe-1.1.0 Werkzeug-0.14.1 click-7.0 flask-1.0.2 itsdangerous-1.1.0
+remote:
+remote: -----> Discovering process types
+remote:        Procfile declares types -> (none)
+remote:
+```
 
-    $ ls
+A `requirements.txt` must be present at the root of your application's repository to deploy.
-    Pipfile		Procfile	web.py
 
-    $ heroku create --buildpack heroku/python
+To specify your python version, you also need a `runtime.txt` file - unless you are using the default Python runtime version.
 
-    $ git push heroku master
+Current default Python Runtime: Python 3.6.12
-    ...
-    -----> Python app detected
-    -----> Installing python-3.6.2
-    -----> Installing pip
-    -----> Installing requirements with latest pipenv...
-           ...
-           Installing dependencies from Pipfile...
-    -----> Discovering process types
-           Procfile declares types -> (none)
 
-A `Pipfile` or `requirements.txt` must be present at the root of your application's repository.
+Alternatively, you can provide a `setup.py` file, or a `Pipfile`.
+Using `pipenv` will generate `runtime.txt` at build time if one of the field `python_version` or `python_full_version` is specified in the `requires` section of your `Pipfile`.
 
-You can also specify the latest production release of this buildpack for upcoming builds of an existing application:
+Specify a Buildpack Version
+---------------------------
+
+You can specify the latest production release of this buildpack for upcoming builds of an existing application:
 
     $ heroku buildpacks:set heroku/python
 
@@ -41,14 +60,37 @@ You can also specify the latest production release of this buildpack for upcomin
 Specify a Python Runtime
 ------------------------
 
-Specific versions of the Python runtime can be specified with a `runtime.txt` file:
+Supported runtime options include:
 
-    $ cat runtime.txt
+- `python-3.9.0`
-    python-2.7.13
+- `python-3.8.7`
+- `python-3.7.9`
+- `python-3.6.12`
+- `python-2.7.18`
 
-Runtime options include:
+## Tests
 
-- `python-3.6.2`
+The buildpack tests use [Docker](https://www.docker.com/) to simulate
-- `python-2.7.13`
+Heroku's [stack images.](https://devcenter.heroku.com/articles/stack)
-- `pypy-5.7.1` (unsupported, experimental)
+
-- `pypy3-5.5.1` (unsupported, experimental)
+To run the test suite against the default stack:
+
+```
+make test
+```
+
+Or to test against a particular stack:
+
+```
+make test STACK=heroku-16
+```
+
+To run only a subset of the tests:
+
+```
+make test TEST_CMD=tests/versions
+```
+
+The tests are run via the vendored
+[shunit2](https://github.com/kward/shunit2)
+test framework.

Rakefile

@@ -0,0 +1 @@
+require 'hatchet/tasks'

bin/compile

@@ -15,61 +15,117 @@
 # Fail fast and fail hard.
 set -eo pipefail
 
-# Standard Library.
+# Used by buildpack-stdlib's metrics features.
 export BPLOG_PREFIX="buildpack.python"
 export BUILDPACK_LOG_FILE=${BUILDPACK_LOG_FILE:-/dev/null}
 
 [ "$BUILDPACK_XTRACE" ] && set -o xtrace
 
-# Prepend proper path for virtualenv hackery. This will be deprecated soon.
+# Prepend proper path for old-school virtualenv hackery.
+# This may not be neccessary.
 export PATH=:/usr/local/bin:$PATH
 
-# Paths.
+# Setup Path variables, for later use in the Buildpack.
 BIN_DIR=$(cd "$(dirname "$0")"; pwd) # absolute path
 ROOT_DIR=$(dirname "$BIN_DIR")
 BUILD_DIR=$1
 CACHE_DIR=$2
 ENV_DIR=$3
 
+# Export Path variables, for use in sub-scripts.
 export BUILD_DIR CACHE_DIR ENV_DIR
 
-# Python defaults
+# Set the base URL for downloading buildpack assets like Python runtimes.
-DEFAULT_PYTHON_VERSION="python-3.6.2"
+# The user can provide BUILDPACK_S3_BASE_URL to specify a custom target.
-DEFAULT_PYTHON_STACK="cedar-14"
+# Note: this is designed for non-Heroku use, as it does not use the user-provided
-PIP_UPDATE="9.0.1"
+# environment variable mechanism (the ENV_DIR).
+S3_BASE_URL="${BUILDPACK_S3_BASE_URL:-"https://heroku-buildpack-python.s3.amazonaws.com"}"
+# This has to be exported since it's used by the geo-libs step which is run in a subshell.
 
-export DEFAULT_PYTHON_VERSION DEFAULT_PYTHON_STACK PIP_UPDATE
+# Default Python Versions
+# shellcheck source=bin/default_pythons
+source "$BIN_DIR/default_pythons"
 
-# Common Problem Warnings
+# Supported Python Branches
+PY39="python-3.9"
+PY38="python-3.8"
+PY37="python-3.7"
+PY36="python-3.6"
+PY35="python-3.5"
+PY34="python-3.4"
+PY27="python-2.7"
+PYPY27="pypy2.7"
+PYPY36="pypy3.6"
+
+# Which stack is used (for binary downloading), if none is provided (e.g. outside of Heroku)?
+# TODO: Remove this and require that STACK be set explicitly.
+DEFAULT_PYTHON_STACK="heroku-18"
+
+# Common Problem Warnings:
+# This section creates a temporary file in which to stick the output of `pip install`.
+# The `warnings` subscript then greps through this for common problems and guides
+# the user towards resolution of known issues.
 WARNINGS_LOG=$(mktemp)
-export WARNINGS_LOG
+RECOMMENDED_PYTHON_VERSION=$DEFAULT_PYTHON_VERSION
-export RECOMMENDED_PYTHON_VERSION=$DEFAULT_PYTHON_VERSION
 
-# Setup vendored tools and pip-pop (pip-diff)
+# The buildpack ships with a few executable tools.
-export PATH=$PATH:$ROOT_DIR/vendor/:$ROOT_DIR/vendor/pip-pop
+# This installs them into the path, so we can execute them directly.
+export PATH=$PATH:$ROOT_DIR/vendor/
 
-# Support Anvil Build_IDs
+# Set environment variables if they weren't set by the platform.
-[ ! "$SLUG_ID" ] && SLUG_ID="defaultslug"
-[ ! "$REQUEST_ID" ] && REQUEST_ID=$SLUG_ID
 [ ! "$STACK" ] && STACK=$DEFAULT_PYTHON_STACK
 
-# Sanitizing environment variables.
+# Sanitize externally-provided environment variables:
-unset GIT_DIR PYTHONHOME PYTHONPATH
+# The following environment variables are either problematic or simply unneccessary
-unset RECEIVE_DATA RUN_KEY BUILD_INFO DEPLOY LOG_TOKEN
+# for the buildpack to have knowledge of, so we unset them, to keep the environment
-unset CYTOKINE_LOG_FILE GEM_PATH
+# as clean and pristine as possible.
+unset PYTHONHOME PYTHONPATH
 
-# Syntax sugar.
+# Import the utils script, which contains helper functions used throughout the buildpack.
 # shellcheck source=bin/utils
 source "$BIN_DIR/utils"
 
-# Import collection of warnings.
+# Import the warnings script, which contains the `pip install` user warning mechanisms
+# (mentioned and explained above)
 # shellcheck source=bin/warnings
 source "$BIN_DIR/warnings"
 
-# we need to put a bunch of symlinks in there later
+if [[ "${STACK}" == "cedar-14" ]]; then
+  mcount "failure.unsupported.cedar-14"
+  puts-warn "The Cedar-14 stack is no longer supported by the latest release of this buildpack."
+  puts-warn
+  puts-warn "Please switch to the Cedar-14 support branch by using this buildpack URL:"
+  puts-warn "https://github.com/heroku/heroku-buildpack-python#cedar-14"
+  puts-warn
+  puts-warn "For instructions on how to change the buildpacks used by an app, see:"
+  puts-warn "https://devcenter.heroku.com/articles/buildpacks#setting-a-buildpack-on-an-application"
+  exit 1
+fi
+
+if [[ -f "${ENV_DIR}/BUILD_WITH_GEO_LIBRARIES" ]]; then
+  mcount "failure.unsupported.BUILD_WITH_GEO_LIBRARIES"
+  puts-warn "The Python buildpack's legacy BUILD_WITH_GEO_LIBRARIES functonality is"
+  puts-warn "no longer supported:"
+  puts-warn "https://devcenter.heroku.com/changelog-items/1947"
+  puts-warn
+  puts-warn "To continue to use GDAL, GEOS or PROJ support, see the migration guide:"
+  puts-warn "https://help.heroku.com/D5INLB1A/python-s-build_with_geo_libraries-legacy-feature-is-no-longer-supported"
+  puts-warn
+  puts-warn "Or if you no longer need those libraries, this message can be hidden by"
+  puts-warn "unsetting the BUILD_WITH_GEO_LIBRARIES environment variable, using:"
+  puts-warn "heroku config:unset BUILD_WITH_GEO_LIBRARIES"
+  exit 1
+fi
+
+# Make the directory in which we will create symlinks from the temporary build directory
+# to `/app`.
+# Symlinks are required, since Python is not a portable installation.
+# More on this topic later.
 mkdir -p /app/.heroku
 
-# Set up outputs under new context
+# This buildpack programatically generates (or simply copies) a number of files for
+# buildpack machinery: an export script, and a number of `.profile.d` scripts. This
+# section declares the locations of those files and targets.
 PROFILE_PATH="$BUILD_DIR/.profile.d/python.sh"
 EXPORT_PATH="$BIN_DIR/../export"
 GUNICORN_PROFILE_PATH="$BUILD_DIR/.profile.d/python.gunicorn.sh"
@@ -78,69 +134,112 @@ WEB_CONCURRENCY_PROFILE_PATH="$BUILD_DIR/.profile.d/WEB_CONCURRENCY.sh"
 # We'll need to send these statics to other scripts we `source`.
 export BUILD_DIR CACHE_DIR BIN_DIR PROFILE_PATH EXPORT_PATH
 
-# Prepend proper environment variables for Python use.
+# Python Environment Variables
+# Set Python-specific environment variables, for running Python within the buildpack.
+# Notes on each variable included.
+
+# PATH is relatively obvious, we need to be able to execute 'python'.
 export PATH=/app/.heroku/python/bin:/app/.heroku/vendor/bin:$PATH
+# Tell Python to not buffer it's stdin/stdout.
 export PYTHONUNBUFFERED=1
+# Set the locale to a well-known and expected standard.
 export LANG=en_US.UTF-8
+# `~/.heroku/vendor` is an place where the buildpack may stick pre-build binaries for known
+# C dependencies. This section configures Python (GCC, more specifically)
+# and pip to automatically include these paths when building binaries.
+# TODO: Stop adding .heroku/vendor here now that the buildpack no longer vendors anything.
 export C_INCLUDE_PATH=/app/.heroku/vendor/include:/app/.heroku/python/include:$C_INCLUDE_PATH
 export CPLUS_INCLUDE_PATH=/app/.heroku/vendor/include:/app/.heroku/python/include:$CPLUS_INCLUDE_PATH
 export LIBRARY_PATH=/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LIBRARY_PATH
 export LD_LIBRARY_PATH=/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LD_LIBRARY_PATH
 export PKG_CONFIG_PATH=/app/.heroku/vendor/lib/pkg-config:/app/.heroku/python/lib/pkg-config:$PKG_CONFIG_PATH
 
+# Global pip options (https://pip.pypa.io/en/stable/user_guide/#environment-variables).
+# Disable pip's warnings about EOL Python since we show our own.
+export PIP_NO_PYTHON_VERSION_WARNING=1
+
+# The Application Code
+# --------------------
+
 # Switch to the repo's context.
 cd "$BUILD_DIR"
 
-# Warn for lack of Procfile.
+# The Cache
-if [[ ! -f Procfile ]]; then
+# ---------
-  puts-warn 'Warning: Your application is missing a Procfile. This file tells Heroku how to run your application.'
-  puts-warn 'Learn more: https://devcenter.heroku.com/articles/procfile'
-fi
 
-# Prepare the cache.
+# The workflow for the Python Buildpack's cache is as follows:
-mkdir -p "$CACHE_DIR"
+#
+# - `~/.heroku/{known-paths}` are copied from the cache into the slug.
+# - The build is executed, modifying `~/.heroku/{known-paths}`.
+# - Once the build is complete, `~/.heroku/{known-paths}` is copied back into the cache.
+
+# Create the cache directory, if it doesn't exist.
+mkdir -p "$CACHE_DIR/.heroku"
 
 # Restore old artifacts from the cache.
 mkdir -p .heroku
 
+# The Python installation.
 cp -R "$CACHE_DIR/.heroku/python" .heroku/ &> /dev/null || true
+# A plain text file which contains the current stack being used (used for cache busting).
 cp -R "$CACHE_DIR/.heroku/python-stack" .heroku/ &> /dev/null || true
+# A plain text file which contains the current python version being used (used for cache busting).
 cp -R "$CACHE_DIR/.heroku/python-version" .heroku/ &> /dev/null || true
-cp -R "$CACHE_DIR/.heroku/vendor" .heroku/ &> /dev/null || true
+# A plain text file which contains the current sqlite3 version being used (used for cache busting).
+cp -R "$CACHE_DIR/.heroku/python-sqlite3-version" .heroku/ &> /dev/null || true
+# "editable" installations of code repositories, via pip or pipenv.
 if [[ -d "$CACHE_DIR/.heroku/src" ]]; then
   cp -R "$CACHE_DIR/.heroku/src" .heroku/ &> /dev/null || true
 fi
 
-# Experimental pre_compile hook.
+# The pre_compile hook. Customers rely on this. Don't remove it.
+# This part of the code is used to allow users to customize their build experience
+# without forking the buildpack by providing a `bin/pre_compile` script, which gets
+# run inline with the buildpack automatically.
+
 # shellcheck source=bin/steps/hooks/pre_compile
 source "$BIN_DIR/steps/hooks/pre_compile"
 
-# Sticky runtimes.
+# Sticky runtimes. If there was a previous build, and it used a given version of Python,
+# continue to use that version of Python in perpituity (warnings will be raised if
+# they are out–of–date).
 if [ -f "$CACHE_DIR/.heroku/python-version" ]; then
-  DEFAULT_PYTHON_VERSION=$(cat "$CACHE_DIR/.heroku/python-version")
+  CACHED_PYTHON_VERSION=$(cat "$CACHE_DIR/.heroku/python-version")
 fi
 
-# Stack fallback for non-declared caches.
+# We didn't always record the stack version. This code is in place because of that.
 if [ -f "$CACHE_DIR/.heroku/python-stack" ]; then
   CACHED_PYTHON_STACK=$(cat "$CACHE_DIR/.heroku/python-stack")
 else
   CACHED_PYTHON_STACK=$STACK
 fi
 
-export CACHED_PYTHON_STACK
-
 # Pipenv Python version support.
+# Detect the version of Python requested from a Pipfile (e.g. python_version or python_full_version).
+# Convert it to a runtime.txt file.
+
 # shellcheck source=bin/steps/pipenv-python-version
 source "$BIN_DIR/steps/pipenv-python-version"
 
-# If no runtime given, assume default version.
+if [[ -f runtime.txt ]]; then
-if [ ! -f runtime.txt ]; then
+  mcount "version.reason.python.specified"
-  echo "$DEFAULT_PYTHON_VERSION" > runtime.txt
+elif [[ -n "${CACHED_PYTHON_VERSION:-}" ]]; then
+  mcount "version.reason.python.cached"
+  echo "${CACHED_PYTHON_VERSION}" > runtime.txt
+else
+  mcount "version.reason.python.default"
+  echo "${DEFAULT_PYTHON_VERSION}" > runtime.txt
 fi
 
+# Create the directory for .profile.d, if it doesn't exist.
 mkdir -p "$(dirname "$PROFILE_PATH")"
+# Create the directory for editable source code installation, if it doesn't exist.
 mkdir -p /app/.heroku/src
 
+# On Heroku CI, builds happen in `/app`. Otherwise, on the Heroku platform,
+# they occur in a temp directory. Beacuse Python is not portable, we must create
+# symlinks to emulate that we are operating in `/app` during the build process.
+# This is (hopefully obviously) because apps end up running from `/app` in production.
 if [[ $BUILD_DIR != '/app' ]]; then
     # python expects to reside in /app, so set up symlinks
     # we will not remove these later so subsequent buildpacks can still invoke it
@@ -149,93 +248,109 @@ if [[ $BUILD_DIR != '/app' ]]; then
     # Note: .heroku/src is copied in later.
 fi
 
-# Install Python.
+# Download / Install Python, from pre-build binaries available on Amazon S3.
-let start=$(nowms)
+# This step also bootstraps pip / setuptools.
+(( start=$(nowms) ))
 # shellcheck source=bin/steps/python
 source "$BIN_DIR/steps/python"
 mtime "python.install.time" "${start}"
 
-# Pipenv support.
+# Install Pipenv dependencies, if a Pipfile was provided.
 # shellcheck source=bin/steps/pipenv
 source "$BIN_DIR/steps/pipenv"
 
 # If no requirements.txt file given, assume `setup.py develop` is intended.
+# This allows for people to ship a setup.py application to Heroku
+
 if [ ! -f requirements.txt ] && [ ! -f Pipfile ]; then
   echo "-e ." > requirements.txt
 fi
 
 # Fix egg-links.
+# Because we're installing things into a different path than we're running them (temp dir vs app dir),
+# We must re-write all of Python's eggpath links to target the proper directory.
 # shellcheck source=bin/steps/eggpath-fix
 source "$BIN_DIR/steps/eggpath-fix"
 
-# Mercurial support.
+# SQLite3 support.
-# shellcheck source=bin/steps/mercurial
+# This sets up and installs sqlite3 dev headers and the sqlite3 binary but not the
-source "$BIN_DIR/steps/mercurial"
+# libsqlite3-0 library since that exists on the stack image.
+# Note: This only applies to Python 2.7.15+ and Python 3.6.6+
+(( start=$(nowms) ))
+# shellcheck source=bin/steps/sqlite3
+source "$BIN_DIR/steps/sqlite3"
+buildpack_sqlite3_install
+mtime "sqlite3.install.time" "${start}"
 
-# Pylibmc support.
+# pip install
-# shellcheck source=bin/steps/pylibmc
+# -----------
-source "$BIN_DIR/steps/pylibmc"
 
-# Libffi support.
+# Install dependencies with pip (where the magic happens).
-# shellcheck source=bin/steps/cryptography
+(( start=$(nowms) ))
-source "$BIN_DIR/steps/cryptography"
-
-# Support for Geo libraries.
-# shellcheck source=bin/steps/geo-libs
-sub_env "$BIN_DIR/steps/geo-libs"
-
-# GDAL support.
-# shellcheck source=bin/steps/gdal
-source "$BIN_DIR/steps/gdal"
-
-# Uninstall removed dependencies with Pip.
-let start=$(nowms)
-# shellcheck source=bin/steps/pip-uninstall
-source "$BIN_DIR/steps/pip-uninstall"
-mtime "pip.uninstall.time" "${start}"
-
-# Install dependencies with Pip (where the magic happens).
-let start=$(nowms)
 # shellcheck source=bin/steps/pip-install
 source "$BIN_DIR/steps/pip-install"
 mtime "pip.install.time" "${start}"
 
 # Support for NLTK corpora.
-let start=$(nowms)
+# Note: this may only work on Python 2.7. I don't think many customers use this functionality,
+# and it should probably be undocumented.
+# (there's an import error on 3.6 that should hopefully be fixed upstream at some point)
+(( start=$(nowms) ))
 sub_env "$BIN_DIR/steps/nltk"
 mtime "nltk.download.time" "${start}"
 
-# Support for pip install -e.
+# Support for editable installations. Here, we are copying pip–created src directory,
+# and copying it into the proper place (the logical place to do this was early, but it must be done here).
 # In CI, $BUILD_DIR is /app.
 if [[ ! "$BUILD_DIR" == "/app" ]]; then
-  rm -fr "$BUILD_DIR/.heroku/src"
+  rm -rf "$BUILD_DIR/.heroku/src"
   deep-cp /app/.heroku/src "$BUILD_DIR/.heroku/src"
 fi
 
 
 # Django collectstatic support.
-let start=$(nowms)
+# The buildpack automatically runs collectstatic for Django applications.
+# This is the cause for the majority of build failures on the Python platform.
+# These failures are intentional — if collectstatic (which can be tricky, at times) fails,
+# your build fails.
+(( start=$(nowms) ))
 sub_env "$BIN_DIR/steps/collectstatic"
 mtime "collectstatic.time" "${start}"
 
-# Create .profile script for application runtime environment variables.
+
+# Progamatically create .profile.d script for application runtime environment variables.
+
+# Set the PATH to include Python / pip / pipenv / etc.
 set_env PATH "\$HOME/.heroku/python/bin:\$PATH"
+# Tell Python to run in unbuffered mode.
 set_env PYTHONUNBUFFERED true
-set_env PYTHONHOME /app/.heroku/python
+# Tell Python where it lives.
-
+set_env PYTHONHOME "\$HOME/.heroku/python"
-set_env LIBRARY_PATH "/app/.heroku/vendor/lib:/app/.heroku/python/lib:\$LIBRARY_PATH"
+# Set variables for C libraries.
-set_env LD_LIBRARY_PATH "/app/.heroku/vendor/lib:/app/.heroku/python/lib:\$LD_LIBRARY_PATH"
+set_env LIBRARY_PATH "\$HOME/.heroku/vendor/lib:\$HOME/.heroku/python/lib:\$LIBRARY_PATH"
-
+set_env LD_LIBRARY_PATH "\$HOME/.heroku/vendor/lib:\$HOME/.heroku/python/lib:\$LD_LIBRARY_PATH"
+# Locale.
 set_default_env LANG en_US.UTF-8
+# The Python hash seed is set to random.
 set_default_env PYTHONHASHSEED random
-set_default_env PYTHONPATH /app/
+# Tell Python to look for Python modules in the /app dir. Don't change this.
+set_default_env PYTHONPATH "\$HOME"
+
+# Python expects to be in /app, if at runtime, it is not, set
+# up symlinks… this can occur when the subdir buildpack is used.
+cat <<EOT >> "$PROFILE_PATH"
+if [[ \$HOME != "/app" ]]; then
+    mkdir -p /app/.heroku
+    ln -nsf "\$HOME/.heroku/python" /app/.heroku/python
+    ln -nsf "\$HOME/.heroku/vendor" /app/.heroku/vendor
+fi
+EOT
 
 # Install sane-default script for $WEB_CONCURRENCY and $FORWARDED_ALLOW_IPS.
 cp "$ROOT_DIR/vendor/WEB_CONCURRENCY.sh" "$WEB_CONCURRENCY_PROFILE_PATH"
 cp "$ROOT_DIR/vendor/python.gunicorn.sh" "$GUNICORN_PROFILE_PATH"
 
-
+# Experimental post_compile hook. Don't remove this.
-# Experimental post_compile hook.
 # shellcheck source=bin/steps/hooks/post_compile
 source "$BIN_DIR/steps/hooks/post_compile"
 
@@ -243,8 +358,7 @@ source "$BIN_DIR/steps/hooks/post_compile"
 # shellcheck source=bin/steps/eggpath-fix2
 source "$BIN_DIR/steps/eggpath-fix2"
 
-# Store new artifacts in cache.
+# Store new artifacts in the cache.
-
 rm -rf "$CACHE_DIR/.heroku/python"
 rm -rf "$CACHE_DIR/.heroku/python-version"
 rm -rf "$CACHE_DIR/.heroku/python-stack"
@@ -255,7 +369,6 @@ mkdir -p "$CACHE_DIR/.heroku"
 cp -R .heroku/python "$CACHE_DIR/.heroku/"
 cp -R .heroku/python-version "$CACHE_DIR/.heroku/"
 cp -R .heroku/python-stack "$CACHE_DIR/.heroku/" &> /dev/null || true
-cp -R .heroku/vendor "$CACHE_DIR/.heroku/" &> /dev/null || true
 if [[ -d .heroku/src ]]; then
   cp -R .heroku/src "$CACHE_DIR/.heroku/" &> /dev/null || true
 fi

bin/default_pythons

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+# Disable unused env var warning, since shellcheck doesn't take into account
+# that this file is sourced. We don't want to use export since it exposes
+# the env vars to subprocesses.
+# shellcheck disable=2034
+
+DEFAULT_PYTHON_VERSION="python-3.6.12"
+LATEST_39="python-3.9.0"
+LATEST_38="python-3.8.7"
+LATEST_37="python-3.7.9"
+LATEST_36="python-3.6.12"
+LATEST_35="python-3.5.10"
+LATEST_34="python-3.4.10"
+LATEST_27="python-2.7.18"
+LATEST_PYPY_36="pypy3.6-7.3.2"
+LATEST_PYPY_27="pypy2.7-7.3.2"

bin/steps/README.MD

@@ -0,0 +1,21 @@
+# Python Buildpack Install Steps
+
+TODO: Add context on Python install steps, such as why symlinking vs copying
+
+## Installing Python packages using Pip
+
+### Convention: Use `python` process to invoke Pip
+
+We don't use this convention (yet) but this is an upcoming change being considered.
+
+This is a bigger concern on Windows than it is in Linux environments, but an
+emerging convention in the Python community is to invoke pip using:
+
+```
+python3 -m pip [options]
+```
+
+Invoking pip this way ensures correct location - python knows where these
+packages are stored because it put them there (defaults to Python's pathing info).
+
+All normal command line options are available using this method.

bin/steps/collectstatic

@@ -11,7 +11,7 @@
 #   - $DEBUG_COLLECTSTATIC: upon failure, print out environment variables.
 
 # shellcheck source=bin/utils
-source $BIN_DIR/utils
+source "$BIN_DIR/utils"
 
 # Location of 'manage.py', if it exists.
 MANAGE_FILE=$(find . -maxdepth 3 -type f -name 'manage.py' -printf '%d\t%P\n' | sort -nk1 | cut -f2 | head -1)
@@ -20,8 +20,8 @@ MANAGE_FILE=${MANAGE_FILE:-fakepath}
 # Legacy file-based support for $DISABLE_COLLECTSTATIC
 [ -f .heroku/collectstatic_disabled ] && DISABLE_COLLECTSTATIC=1
 
-# Ensure that Django is explicitly specified in requirements.txt
+# Ensure that Django is actually installed.
-sp-grep -s django && DJANGO_INSTALLED=1
+is_module_available 'django' && DJANGO_INSTALLED=1
 
 
 if [ ! "$DISABLE_COLLECTSTATIC" ] && [ -f "$MANAGE_FILE" ] && [ "$DJANGO_INSTALLED" ]; then
@@ -30,7 +30,13 @@ if [ ! "$DISABLE_COLLECTSTATIC" ] && [ -f "$MANAGE_FILE" ] && [ "$DJANGO_INSTALL
     puts-step "$ python $MANAGE_FILE collectstatic --noinput"
 
     # Run collectstatic, cleanup some of the noisy output.
-    python "$MANAGE_FILE" collectstatic --noinput --traceback 2>&1 | sed '/^Post-processed/d;/^Copying/d;/^$/d' | indent
+    PYTHONPATH=${PYTHONPATH:-.}
+    export PYTHONPATH
+
+    # Create a temporary file for collecting the collectstaic logs.
+    COLLECTSTATIC_LOG=$(mktemp)
+
+    python "$MANAGE_FILE" collectstatic --noinput --traceback 2>&1 | tee "$COLLECTSTATIC_LOG" | sed '/^Post-processed/d;/^Copying/d;/^$/d' | indent
     COLLECTSTATIC_STATUS="${PIPESTATUS[0]}"
 
     set -e
@@ -38,6 +44,22 @@ if [ ! "$DISABLE_COLLECTSTATIC" ] && [ -f "$MANAGE_FILE" ] && [ "$DJANGO_INSTALL
     # Display a warning if collectstatic failed.
     [ "$COLLECTSTATIC_STATUS" -ne 0 ] && {
 
+        if grep -q 'SyntaxError' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.syntax-error"
+
+        elif grep -q 'ImproperlyConfigured' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.improper-configuration"
+
+        elif grep -q 'The CSS file' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.fancy-references"
+
+        elif grep -q 'OSError' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.missing-file"
+
+        else
+            mcount "failure.collectstatic.other"
+        fi
+
         echo
         echo " !     Error while running '$ python $MANAGE_FILE collectstatic --noinput'."
         echo "       See traceback above for details."

bin/steps/cryptography

@@ -1,38 +0,0 @@
-#!/usr/bin/env bash
-
-# This script serves as the cffi build step of the
-# [**Python Buildpack**](https://github.com/heroku/heroku-buildpack-python)
-# compiler.
-#
-# A [buildpack](https://devcenter.heroku.com/articles/buildpacks) is an
-# adapter between a Python application and Heroku's runtime.
-#
-# This script is invoked by [`bin/compile`](/).
-
-if [[ "$STACK" == "heroku-16" ]]; then
-    # libffi is pre-installed in the stack image so there is no need to vendor it.
-    return 0
-fi
-
-# The location of the pre-compiled libffi binary.
-VENDORED_LIBFFI="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/libffi.tar.gz"
-
-PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"
-
-# Syntax sugar.
-# shellcheck source=bin/utils
-source "$BIN_DIR/utils"
-
-# If a package using cffi exists within requirements, use vendored libffi.
-if (pip-grep -s requirements.txt argon2-cffi bcrypt cffi cryptography django[argon2] Django[argon2] django[bcrypt] Django[bcrypt] PyNaCl pyOpenSSL PyOpenSSL requests[security] misaka &> /dev/null) then
-
-  if [ ! -d ".heroku/vendor/lib/libffi-3.1" ]; then
-    echo "-----> Noticed cffi. Bootstrapping libffi."
-    mkdir -p .heroku/vendor
-    # Download and extract libffi into target vendor directory.
-    curl "$VENDORED_LIBFFI" -s | tar zxv -C .heroku/vendor &> /dev/null
-  fi
-
-  LIBFFI=$(pwd)/vendor
-  export LIBFFI
-fi

bin/steps/gdal

@@ -1,34 +0,0 @@
-#!/usr/bin/env bash
-
-# This script serves as the GDAL build step of the
-# [**Python Buildpack**](https://github.com/heroku/heroku-buildpack-python)
-# compiler.
-#
-# A [buildpack](https://devcenter.heroku.com/articles/buildpacks) is an
-# adapter between a Python application and Heroku's runtime.
-#
-# This script is invoked by [`bin/compile`](/).
-
-# The location of the pre-compiled cryptography binary.
-VENDORED_GDAL="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/gdal.tar.gz"
-
-PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"
-
-# Syntax sugar.
-# shellcheck source=bin/utils
-source "$BIN_DIR/utils"
-
-# If GDAL exists within requirements, use vendored gdal.
-if (pip-grep -s requirements.txt GDAL gdal pygdal &> /dev/null) then
-
-  if [ ! -f ".heroku/vendor/bin/gdalserver" ]; then
-    echo "-----> Noticed GDAL. Bootstrapping gdal."
-    mkdir -p .heroku/vendor
-    # Download and extract cryptography into target vendor directory.
-    curl "$VENDORED_GDAL" -s | tar zxv -C .heroku/vendor &> /dev/null
-  fi
-
-  GDAL=$(pwd)/vendor
-  export GDAL
-fi
-

bin/steps/geo-libs

@@ -1,39 +0,0 @@
-#!/usr/bin/env bash
-
-# This script serves as the GDAL build step of the
-# [**Python Buildpack**](https://github.com/heroku/heroku-buildpack-python)
-# compiler.
-#
-# A [buildpack](https://devcenter.heroku.com/articles/buildpacks) is an
-# adapter between a Python application and Heroku's runtime.
-#
-# This script is invoked by [`bin/compile`](/).
-
-# The location of the pre-compiled cryptography binary.
-VENDORED_GDAL="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/gdal.tar.gz"
-VENDORED_GEOS="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/geos.tar.gz"
-VENDORED_PROJ="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/proj.tar.gz"
-
-PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"
-
-# Syntax sugar.
-# shellcheck source=bin/utils
-source "$BIN_DIR/utils"
-
-# If GDAL exists within requirements, use vendored gdal.
-if [[ "$BUILD_WITH_GEO_LIBRARIES" ]]; then
-
-  if [ ! -f ".heroku/vendor/bin/proj" ]; then
-    echo "-----> Bootstrapping gdal, geos, proj."
-    mkdir -p .heroku/vendor
-    # Download and extract cryptography into target vendor directory.
-    curl "$VENDORED_GDAL" -s | tar zxv -C .heroku/vendor &> /dev/null
-    curl "$VENDORED_GEOS" -s | tar zxv -C .heroku/vendor &> /dev/null
-    curl "$VENDORED_PROJ" -s | tar zxv -C .heroku/vendor &> /dev/null
-    cp /usr/lib/x86_64-linux-gnu/libjasper.so* ".heroku/vendor/lib/."
-  fi
-
-  GDAL=$(pwd)/vendor
-  export GDAL
-fi
-

bin/steps/mercurial

@@ -1,6 +0,0 @@
-#!/usr/bin/env bash
-
-# Install Mercurial if it appears to be required.
-if (grep -Fiq "hg+" requirements.txt) then
-    /app/.heroku/python/bin/pip install  mercurial | cleanup | indent
-fi

bin/steps/nltk

@@ -14,8 +14,8 @@
 source "$BIN_DIR/utils"
 
 # Check that nltk was installed by pip, otherwise obviously not needed
-if sp-grep -s nltk; then
+if is_module_available 'nltk'; then
-    puts-step "Downloading NLTK corpora..."
+    puts-step "Downloading NLTK corpora…"
 
     nltk_packages_definition="$BUILD_DIR/nltk.txt"
 
@@ -27,6 +27,8 @@ if sp-grep -s nltk; then
         python -m nltk.downloader -d "$BUILD_DIR/.heroku/python/nltk_data" "${nltk_packages[@]}" | indent
         set_env NLTK_DATA "/app/.heroku/python/nltk_data"
 
+        mcount "buildvar.NLTK_PACKAGES_DEFINITION"
+        mcount "steps.nltk"
     else
         puts-warn "'nltk.txt' not found, not downloading any corpora"
         puts-warn "Learn more: https://devcenter.heroku.com/articles/python-nltk"

bin/steps/pip-install

@@ -1,12 +1,53 @@
 #!/usr/bin/env bash
 
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
+
 if [ ! "$SKIP_PIP_INSTALL" ]; then
 
     # Install dependencies with Pip.
     puts-step "Installing requirements with pip"
 
+    # Set Pip env vars
+    # This reads certain environment variables set on the Heroku app config
+    # and makes them accessible to the pip install process.
+    #
+    # PIP_EXTRA_INDEX_URL allows for an alternate pypi URL to be used.
+    if [[ -r "$ENV_DIR/PIP_EXTRA_INDEX_URL" ]]; then
+        PIP_EXTRA_INDEX_URL="$(cat "$ENV_DIR/PIP_EXTRA_INDEX_URL")"
+        export PIP_EXTRA_INDEX_URL
+        mcount "buildvar.PIP_EXTRA_INDEX_URL"
+    fi
+
     set +e
 
+    # Set SLUGIFY_USES_TEXT_UNIDECODE, required for Airflow versions >=1.10
+    if [[ -r "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE" ]]; then
+        SLUGIFY_USES_TEXT_UNIDECODE="$(cat "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE")"
+        export SLUGIFY_USES_TEXT_UNIDECODE
+        mcount "buildvar.SLUGIFY_USES_TEXT_UNIDECODE"
+    fi
+
+    set +e
+
+    # Measure that we're using pip.
+    mcount "tool.pip"
+
+    # Count expected build failures.
+    if grep -q '==0.0.0' requirements.txt; then
+        mcount "failure.none-version"
+    fi
+
+    if grep -qi '^django==1.*' requirements.txt; then
+        puts-warn "Your Django version is nearing the end of its community support."
+        puts-warn "Upgrade to continue to receive security updates and for the best experience with Django."
+        puts-warn "For more information, check out https://www.djangoproject.com/download/#supported-versions"
+    fi
+
+    if [ ! -f "$BUILD_DIR/.heroku/python/bin/pip" ]; then
+        exit 1
+    fi
+
     /app/.heroku/python/bin/pip install -r "$BUILD_DIR/requirements.txt" --exists-action=w --src=/app/.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | tee "$WARNINGS_LOG" | cleanup | indent
     PIP_STATUS="${PIPESTATUS[0]}"
     set -e
@@ -14,13 +55,18 @@ if [ ! "$SKIP_PIP_INSTALL" ]; then
     show-warnings
 
     if [[ ! $PIP_STATUS -eq 0 ]]; then
+        mcount "failure.pip-install"
         exit 1
     fi
 
-
-    # Smart Requirements handling
     cp requirements.txt .heroku/python/requirements-declared.txt
     /app/.heroku/python/bin/pip freeze --disable-pip-version-check > .heroku/python/requirements-installed.txt
 
-    echo
+    # Install test dependencies, for CI.
+    if [ "$INSTALL_TEST" ]; then
+        if [[ -f "$1/requirements-test.txt" ]]; then
+            puts-step "Installing test dependencies…"
+            /app/.heroku/python/bin/pip install -r "$1/requirements-test.txt" --exists-action=w --src=./.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | cleanup | indent
+        fi
+    fi
 fi

bin/steps/pip-uninstall

@@ -1,20 +0,0 @@
-#!/usr/bin/env bash
-
-set +e
-# Install dependencies with Pip.
-
-if [[ -f .heroku/python/requirements-declared.txt ]]; then
-
-  cp .heroku/python/requirements-declared.txt requirements-declared.txt
-
-  pip-diff --stale requirements-declared.txt requirements.txt --exclude setuptools pip wheel > .heroku/python/requirements-stale.txt
-
-  rm -fr requirements-declared.txt
-
-  if [[ -s .heroku/python/requirements-stale.txt ]]; then
-    puts-step "Uninstalling stale dependencies"
-    /app/.heroku/python/bin/pip uninstall -r .heroku/python/requirements-stale.txt -y --exists-action=w | cleanup | indent
-  fi
-fi
-
-set -e

bin/steps/pipenv

@@ -1,21 +1,82 @@
 #!/usr/bin/env bash
 
-# Pipenv support (Generate requriements.txt with pipenv).
+# export CLINT_FORCE_COLOR=1
-if [[ -f Pipfile ]]; then
+# export PIPENV_FORCE_COLOR=1
-    if [[ ! -f requirements.txt ]]; then
+# shellcheck source=bin/utils
-        puts-step "Installing requirements with latest pipenv..."
+source "$BIN_DIR/utils"
+set -e
 
-        # Install pipenv.
+if [[ -f Pipfile.lock ]]; then
-        /app/.heroku/python/bin/pip install pipenv --upgrade &> /dev/null
+    if [[ -f .heroku/python/Pipfile.lock.sha256 ]]; then
+        if [[ $(openssl dgst -sha256 Pipfile.lock) == $(cat .heroku/python/Pipfile.lock.sha256) ]]; then
+            # Don't skip installation if there are git deps.
+            if ! grep -q 'git' Pipfile.lock; then
+                echo "Skipping installation, as Pipfile.lock hasn't changed since last deploy." | indent
 
-        # Install the dependencies.
+                mcount "tool.pipenv"
-        /app/.heroku/python/bin/pipenv install --system --skip-lock 2>&1 | indent
+                export SKIP_PIPENV_INSTALL=1
+                export SKIP_PIP_INSTALL=1
+            fi
+        fi
+    fi
+fi
+
+
+if [ ! "$SKIP_PIPENV_INSTALL" ]; then
+    # Pipenv support (Generate requirements.txt with pipenv).
+    if [[ -f Pipfile ]]; then
+        # Measure that we're using Pipenv.
+        mcount "tool.pipenv"
 
         # Skip pip install, later.
         export SKIP_PIP_INSTALL=1
 
-        # Pip freeze, for compatibility.
+        # Set Pip env vars
-        /app/.heroku/python/bin/pip freeze > requirements.txt
+        # This reads certain environment variables set on the Heroku app config
-
+        # and makes them accessible to the pip install process.
+        #
+        # PIP_EXTRA_INDEX_URL allows for an alternate pypi URL to be used.
+        if [[ -r "$ENV_DIR/PIP_EXTRA_INDEX_URL" ]]; then
+            PIP_EXTRA_INDEX_URL="$(cat "$ENV_DIR/PIP_EXTRA_INDEX_URL")"
+            export PIP_EXTRA_INDEX_URL
+            mcount "buildvar.PIP_EXTRA_INDEX_URL"
         fi
+
+        # Set SLUGIFY_USES_TEXT_UNIDECODE, required for Airflow versions >=1.10
+        if [[ -r "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE" ]]; then
+            SLUGIFY_USES_TEXT_UNIDECODE="$(cat "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE")"
+            export SLUGIFY_USES_TEXT_UNIDECODE
+            mcount "buildvar.SLUGIFY_USES_TEXT_UNIDECODE"
+        fi
+
+        export PIPENV_VERSION="2018.5.18"
+
+        # Install pipenv.
+        # Due to weird old pip behavior and pipenv behavior, pipenv upgrades pip
+        # to latest if only --upgrade is specified. Specify upgrade strategy to
+        # avoid this eager behavior.
+        /app/.heroku/python/bin/pip install pipenv==$PIPENV_VERSION --upgrade --upgrade-strategy only-if-needed &> /dev/null
+
+        # Install the test dependencies, for CI.
+        if [ "$INSTALL_TEST" ]; then
+            puts-step "Installing test dependencies…"
+            /app/.heroku/python/bin/pipenv install --dev --system --deploy 2>&1 | cleanup | indent
+
+        # Install the dependencies.
+        elif [[ ! -f Pipfile.lock ]]; then
+            puts-step "Installing dependencies with Pipenv $PIPENV_VERSION…"
+            /app/.heroku/python/bin/pipenv install --system --skip-lock 2>&1 | indent
+
+        else
+            pipenv-to-pip Pipfile.lock > requirements.txt
+            cp requirements.txt .heroku/python/requirements-declared.txt
+            openssl dgst -sha256 Pipfile.lock > .heroku/python/Pipfile.lock.sha256
+
+            puts-step "Installing dependencies with Pipenv $PIPENV_VERSION…"
+            /app/.heroku/python/bin/pipenv install --system --deploy 2>&1 | indent
+        fi
+    fi
+else
+    export SKIP_PIP_INSTALL=1
+    pipenv-to-pip Pipfile.lock > requirements.txt
 fi

bin/steps/pipenv-python-version

@@ -6,20 +6,36 @@ if [[ -f $BUILD_DIR/Pipfile ]]; then
 
     if [[ ! -f $BUILD_DIR/runtime.txt ]]; then
         if [[ ! -f $BUILD_DIR/Pipfile.lock ]]; then
-            puts-warn "No 'pipfile.lock' found! We recommend you commit this into your repository."
+            puts-warn "No 'Pipfile.lock' found! We recommend you commit this into your repository."
         fi
         if [[ -f $BUILD_DIR/Pipfile.lock ]]; then
             set +e
-            PYTHON=$(jq -r '._meta.requires.python_version' "$BUILD_DIR/Pipfile.lock")
+            PYTHON=$(jq -r '._meta.requires.python_full_version' "$BUILD_DIR/Pipfile.lock")
+            if [[ "$PYTHON" != "null" ]]; then
+                echo "python-$PYTHON" > "$BUILD_DIR/runtime.txt"
+            fi
             set -e
 
+            if [[ "$PYTHON" == "null" ]]; then
+                PYTHON=$(jq -r '._meta.requires.python_version' "$BUILD_DIR/Pipfile.lock")
                 if [ "$PYTHON" = 2.7 ]; then
-                echo "python-2.7.13" > "$BUILD_DIR/runtime.txt"
+                    echo "$LATEST_27" > "$BUILD_DIR/runtime.txt"
                 fi
                 if [ "$PYTHON" = 3.6 ]; then
-                echo "python-3.6.2" > "$BUILD_DIR/runtime.txt"
+                    echo "$LATEST_36" > "$BUILD_DIR/runtime.txt"
                 fi
+                if [ "$PYTHON" = 3.7 ]; then
+                    echo "$LATEST_37" > "$BUILD_DIR/runtime.txt"
+                fi
+                if [ "$PYTHON" = 3.8 ]; then
+                    echo "$LATEST_38" > "$BUILD_DIR/runtime.txt"
+                fi
+                if [ "$PYTHON" = 3.9 ]; then
+                    echo "$LATEST_39" > "$BUILD_DIR/runtime.txt"
+                fi
+            fi
+
+
         fi
     fi
 fi
-

bin/steps/pylibmc

@@ -1,36 +0,0 @@
-#!/usr/bin/env bash
-
-# This script serves as the Pylibmc build step of the
-# [**Python Buildpack**](https://github.com/heroku/heroku-buildpack-python)
-# compiler.
-#
-# A [buildpack](https://devcenter.heroku.com/articles/buildpacks) is an
-# adapter between a Python application and Heroku's runtime.
-#
-# This script is invoked by [`bin/compile`](/).
-
-if [[ "$STACK" == "heroku-16" ]]; then
-    # libmemcached is pre-installed in the stack image so there is no need to vendor it.
-    return 0
-fi
-
-# The location of the pre-compiled libmemcached binary.
-VENDORED_MEMCACHED="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/libmemcache.tar.gz"
-
-# Syntax sugar.
-# shellcheck source=bin/utils
-source "$BIN_DIR/utils"
-
-# If pylibmc exists within requirements, use vendored libmemcached.
-if (pip-grep -s requirements.txt pylibmc &> /dev/null) then
-
-  if [ ! -d ".heroku/vendor/lib/sasl2" ]; then
-    echo "-----> Noticed pylibmc. Bootstrapping libmemcached."
-    mkdir -p .heroku/vendor
-    # Download and extract libmemcached into target vendor directory.
-    curl "$VENDORED_MEMCACHED" -s | tar zxv -C .heroku/vendor &> /dev/null
-  fi
-
-  LIBMEMCACHED=$(pwd)/vendor
-  export LIBMEMCACHED
-fi

bin/steps/python

@@ -4,29 +4,130 @@ set +e
 runtime-fixer runtime.txt
 PYTHON_VERSION=$(cat runtime.txt)
 
+# The location of the pre-compiled python binary.
+VENDORED_PYTHON="${S3_BASE_URL}/${STACK}/runtimes/${PYTHON_VERSION}.tar.gz"
+
+SECURITY_UPDATE="Python has released a security update! Please consider upgrading to"
+SECURITY_UPDATE_PYPY="The PyPy project has released a security update! Please consider upgrading to"
+
+ONLY_SUPPORTED_2_VERSION="Only the latest version of Python 2 is supported on the platform. Please consider upgrading to"
+
+PYTHON_2_EOL_UPDATE="Python 2 has reached it's community EOL. Upgrade your Python runtime to maintain a secure application as soon as possible."
+
+# check if runtime exists
+if curl --output /dev/null --silent --head --fail "$VENDORED_PYTHON"; then
+  if [[ "$PYTHON_VERSION" == $PY39* ]]; then
+    if [ "$PYTHON_VERSION" != "$LATEST_39" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_39"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY38* ]]; then
+    # do things to alert the user of security release available
+    if [ "$PYTHON_VERSION" != "$LATEST_38" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_38"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY37* ]]; then
+    # do things to alert the user of security release available
+    if [ "$PYTHON_VERSION" != "$LATEST_37" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_37"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY36* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_36" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_36"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY35* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_35" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_35"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY34* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_34" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_34"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY27* ]]; then
+    puts-warn "$PYTHON_2_EOL_UPDATE"
+    echo "       Learn More: https://devcenter.heroku.com/articles/python-2-7-eol-faq"
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_27" ]; then
+      puts-warn "$ONLY_SUPPORTED_2_VERSION" "$LATEST_27"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PYPY27* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_PYPY_27" ]; then
+      puts-warn "$SECURITY_UPDATE_PYPY" "$LATEST_PYPY_27"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PYPY36* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_PYPY_36" ]; then
+      puts-warn "$SECURITY_UPDATE_PYPY" "$LATEST_PYPY_36"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+else
+  puts-warn "Requested runtime ($PYTHON_VERSION) is not available for this stack ($STACK)."
+  puts-warn "Aborting.  More info: https://devcenter.heroku.com/articles/python-support"
+  exit 1
+fi
+
+mcount "version.python.${PYTHON_VERSION}"
+
 if [[ "$STACK" != "$CACHED_PYTHON_STACK" ]]; then
     puts-step "Stack has changed from $CACHED_PYTHON_STACK to $STACK, clearing cache"
-    rm -fr .heroku/python-stack .heroku/python-version .heroku/python .heroku/vendor
+    rm -rf .heroku/python-stack .heroku/python-version .heroku/python .heroku/vendor .heroku/python .heroku/python-sqlite3-version
 fi
 
 if [ -f .heroku/python-version ]; then
   if [ ! "$(cat .heroku/python-version)" = "$PYTHON_VERSION" ]; then
       puts-step "Found $(cat .heroku/python-version), removing"
-      rm -fr .heroku/python
+      rm -rf .heroku/python
   else
     SKIP_INSTALL=1
   fi
 fi
 
+# Check if we should reinstall python dependencies
+if [[ ! -f "$CACHE_DIR/.heroku/requirements.txt" ]]; then
+  # IF there's no cached dependencies, update cached version of requirements.txt
+  # This should only run for new apps and first deploys after this update
+  cp -R "$BUILD_DIR/requirements.txt" "$CACHE_DIR/.heroku/requirements.txt"
+else
+  # IF there IS a cached directory, check for differences with the new one
+  if ! diff "$BUILD_DIR/requirements.txt" "$CACHE_DIR/.heroku/requirements.txt" &> /dev/null; then
+    puts-step "Requirements file has been changed, clearing cached dependencies"
+    # if there are any differences, clear the Python cache
+    # Installing Python over again does not take noticably more time
+    cp -R "$BUILD_DIR/requirements.txt" "$CACHE_DIR/.heroku/requirements.txt"
+    rm -rf .heroku/python
+    unset SKIP_INSTALL
+  else
+    puts-step "No change in requirements detected, installing from cache"
+  fi
+fi
+
 if [ ! "$SKIP_INSTALL" ]; then
     puts-step "Installing $PYTHON_VERSION"
 
     # Prepare destination directory.
     mkdir -p .heroku/python
 
-    mcount "version.python.$PYTHON_VERSION"
+    if ! curl "${VENDORED_PYTHON}" -s | tar zxv -C .heroku/python &> /dev/null; then
-
-    if ! curl "https://lang-python.s3.amazonaws.com/$STACK/runtimes/$PYTHON_VERSION.tar.gz" -s | tar zxv -C .heroku/python &> /dev/null; then
       puts-warn "Requested runtime ($PYTHON_VERSION) is not available for this stack ($STACK)."
       puts-warn "Aborting.  More info: https://devcenter.heroku.com/articles/python-support"
       exit 1
@@ -35,23 +136,58 @@ if [ ! "$SKIP_INSTALL" ]; then
   # Record for future reference.
   echo "$PYTHON_VERSION" > .heroku/python-version
   echo "$STACK" > .heroku/python-stack
-  FRESH_PYTHON=true
 
   hash -r
 fi
 
-# If Pip isn't up to date:
+set -e
-if [ "$FRESH_PYTHON" ] || [[ ! $(pip --version) == *$PIP_UPDATE* ]]; then
 
-  puts-step "Installing pip"
+PIP_VERSION='20.1.1'
-
+# Must use setuptools <47.2.0 until we fix:
-  # Remove old installations.
+# https://github.com/heroku/heroku-buildpack-python/issues/1006
-  rm -fr /app/.heroku/python/lib/python2.7/site-packages/pip-*
+SETUPTOOLS_VERSION='47.1.1'
-  rm -fr /app/.heroku/python/lib/python2.7/site-packages/setuptools-*
+WHEEL_VERSION='0.34.2'
-
-  /app/.heroku/python/bin/python "$ROOT_DIR/vendor/get-pip.py" &> /dev/null
 
+if [[ "${PYTHON_VERSION}" == ${PY34}* ]]; then
+  # Python 3.4 support was dropped in pip 19.2+, setuptools 44+ and wheel 0.34+.
+  PIP_VERSION='19.1.1'
+  SETUPTOOLS_VERSION='43.0.0'
+  WHEEL_VERSION='0.33.6'
+elif [[ "${PYTHON_VERSION}" == ${PY27}* || "${PYTHON_VERSION}" == ${PYPY27}* ]]; then
+  # Python 2.7 support was dropped in setuptools 45+.
+  SETUPTOOLS_VERSION='44.1.1'
 fi
 
-set -e
+# We don't use get-pip.py, since:
+#  - it uses `--force-reinstall`, which is unnecessary here and slows down repeat builds
+#  - it means downloading pip twice (once embedded in get-pip.py, and again during
+#    the install, since get-pip.py can't install the embedded version directly)
+#  - we would still have to manage several versions of get-pip.py, to support older Pythons.
+# Instead, we use the pip wheel to install itself, using the method described here:
+# https://github.com/pypa/pip/issues/2351#issuecomment-69994524
+PIP_WHEEL_FILENAME="pip-${PIP_VERSION}-py2.py3-none-any.whl"
+PIP_WHEEL_URL="${S3_BASE_URL}/common/${PIP_WHEEL_FILENAME}"
+PIP_WHEEL="${TMPDIR:-/tmp}/${PIP_WHEEL_FILENAME}"
+
+if ! curl -sSf "${PIP_WHEEL_URL}" -o "$PIP_WHEEL"; then
+  mcount "failure.python.download-pip"
+  puts-warn "Failed to download pip"
+  exit 1
+fi
+
+if [[ -f "$BUILD_DIR/Pipfile" ]]; then
+  # The buildpack is pinned to old pipenv, which requires older pip.
+  # Pip 9.0.2 doesn't support installing itself from a wheel, so we have to use split
+  # versions here (ie: installer pip version different from target pip version).
+  PIP_VERSION='9.0.2'
+  PIP_TO_INSTALL="pip==${PIP_VERSION}"
+else
+  PIP_TO_INSTALL="${PIP_WHEEL}"
+fi
+
+puts-step "Installing pip ${PIP_VERSION}, setuptools ${SETUPTOOLS_VERSION} and wheel ${WHEEL_VERSION}"
+
+/app/.heroku/python/bin/python "${PIP_WHEEL}/pip" install --quiet --disable-pip-version-check --no-cache \
+  "${PIP_TO_INSTALL}" "setuptools==${SETUPTOOLS_VERSION}" "wheel==${WHEEL_VERSION}"
+
 hash -r

bin/steps/sqlite3

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
+
+sqlite3_install() {
+  HEROKU_PYTHON_DIR="$1"
+  HEADERS_ONLY="$3"
+
+  mkdir -p "$HEROKU_PYTHON_DIR"
+
+  APT_CACHE_DIR="$HEROKU_PYTHON_DIR/apt/cache"
+  APT_STATE_DIR="$HEROKU_PYTHON_DIR/apt/state"
+
+  mkdir -p "$APT_CACHE_DIR/archives/partial"
+  mkdir -p "$APT_STATE_DIR/lists/partial"
+
+  APT_OPTIONS="-o debug::nolocking=true"
+  APT_OPTIONS="$APT_OPTIONS -o dir::cache=$APT_CACHE_DIR"
+  APT_OPTIONS="$APT_OPTIONS -o dir::state=$APT_STATE_DIR"
+  APT_OPTIONS="$APT_OPTIONS -o dir::etc::sourcelist=/etc/apt/sources.list"
+
+  apt-get $APT_OPTIONS update > /dev/null 2>&1
+  if [ -z "$HEADERS_ONLY" ]; then
+    apt-get $APT_OPTIONS -y -d --reinstall install libsqlite3-dev sqlite3 > /dev/null 2>&1
+  else
+    apt-get $APT_OPTIONS -y -d --reinstall install libsqlite3-dev
+  fi
+
+  find "$APT_CACHE_DIR/archives/" -name "*.deb" -exec dpkg -x {} "$HEROKU_PYTHON_DIR/sqlite3/" \;
+
+  mkdir -p "$HEROKU_PYTHON_DIR/include"
+  mkdir -p "$HEROKU_PYTHON_DIR/lib"
+
+  # remove old sqlite3 libraries/binaries
+  find "$HEROKU_PYTHON_DIR/include/" -name "sqlite3*.h" -exec rm -f {} \;
+  find "$HEROKU_PYTHON_DIR/lib/" -name "libsqlite3.*" -exec rm -f {} \;
+  rm -f "$HEROKU_PYTHON_DIR/lib/pkgconfig/sqlite3.pc"
+  rm -f "$HEROKU_PYTHON_DIR/bin/sqlite3"
+
+  # copy over sqlite3 headers & bins and setup linking against the stack image library
+  mv "$HEROKU_PYTHON_DIR/sqlite3/usr/include/"* "$HEROKU_PYTHON_DIR/include/"
+  mv "$HEROKU_PYTHON_DIR/sqlite3/usr/lib/x86_64-linux-gnu"/libsqlite3.*a "$HEROKU_PYTHON_DIR/lib/"
+  mkdir -p "$HEROKU_PYTHON_DIR/lib/pkgconfig"
+  # set the right prefix/lib directories
+  sed -e 's/prefix=\/usr/prefix=\/app\/.heroku\/python/' -e 's/\/x86_64-linux-gnu//' "$HEROKU_PYTHON_DIR/sqlite3/usr/lib/x86_64-linux-gnu/pkgconfig/sqlite3.pc" > "$HEROKU_PYTHON_DIR/lib/pkgconfig/sqlite3.pc"
+  # need to point the libsqlite3.so to the stack image library for /usr/bin/ld -lsqlite3
+  SQLITE3_LIBFILE="/usr/lib/x86_64-linux-gnu/$(readlink -n "$HEROKU_PYTHON_DIR/sqlite3/usr/lib/x86_64-linux-gnu/libsqlite3.so")"
+  ln -s "$SQLITE3_LIBFILE" "$HEROKU_PYTHON_DIR/lib/libsqlite3.so"
+  if [ -z "$HEADERS_ONLY" ]; then
+    mv "$HEROKU_PYTHON_DIR/sqlite3/usr/bin"/* "$HEROKU_PYTHON_DIR/bin/"
+  fi
+
+  # cleanup
+  rm -rf "$HEROKU_PYTHON_DIR/sqlite3/"
+  rm -rf "$HEROKU_PYTHON_DIR/apt/"
+}
+
+buildpack_sqlite3_install() {
+  HEROKU_PYTHON_DIR="$BUILD_DIR/.heroku/python"
+
+  SQLITE3_VERSION_FILE="$BUILD_DIR/.heroku/python-sqlite3-version"
+  if [ -f "$SQLITE3_VERSION_FILE" ]; then
+    INSTALLED_SQLITE3_VERSION=$(cat "$SQLITE3_VERSION_FILE")
+  fi
+
+  puts-step "Installing SQLite3"
+
+  if sqlite3_install "$BUILD_DIR/.heroku/python" ; then
+    mcount "success.python.sqlite3"
+  else
+    echo "Sqlite3 failed to install."
+    mcount "failure.python.sqlite3"
+  fi
+
+  mkdir -p "$CACHE_DIR/.heroku/"
+}

bin/test-compile

@@ -6,8 +6,8 @@ BIN_DIR=$(cd "$(dirname "$0")" || return; pwd) # absolute path
 # shellcheck source=bin/utils
 source "$BIN_DIR/utils"
 
-DISABLE_COLLECTSTATIC=1 "$(dirname "${0:-}")/compile" "$1" "$2" "$3"
+# Locale support for Pipenv.
+export LC_ALL=C.UTF-8
+export LANG=C.UTF-8
 
-if [[ -f "$1/requirements-test.txt" ]]; then
+DISABLE_COLLECTSTATIC=1 INSTALL_TEST=1 "$(dirname "${0:-}")/compile" "$1" "$2" "$3"
-    /app/.heroku/python/bin/pip install -r "$1/requirements-test.txt" --exists-action=w --src=./.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | cleanup | indent
-fi

bin/utils

@@ -2,12 +2,13 @@
 shopt -s extglob
 shopt -s nullglob
 
-# The standard library.
+# This is necessary since this script is sometimes sourced from
-if [[ ! -f  /tmp/stdlib.sh ]]; then
+# subshells that don't have the variables from bin/compile.
-  curl --retry 3 -s https://lang-common.s3.amazonaws.com/buildpack-stdlib/v8/stdlib.sh > /tmp/stdlib.sh
+# Remove this once we no longer wrap all the things in `sub_env`.
-fi
+BIN_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
-# shellcheck source=/dev/null
+ROOT_DIR=$(dirname "${BIN_DIR}")
-source /tmp/stdlib.sh
+# shellcheck source=vendor/buildpack-stdlib_v8.sh
+source "${ROOT_DIR}/vendor/buildpack-stdlib_v8.sh"
 
 if [ "$(uname)" == Darwin ]; then
     sed() { command sed -l "$@"; }
@@ -58,3 +59,48 @@ measure-size() {
   echo "$(du -s .heroku/python 2>/dev/null || echo 0) | awk '{print $1}')"
 }
 
+# Python version operator >
+version_gt() {
+  test "$(printf '%s\n' "$@" | sort -V | head -n 1)" != "$1";
+}
+
+# Python verison operator >=
+version_gte() {
+  if [ "$1" == "$2" ]; then
+    return 0
+  fi
+
+  version_gt "$1" "$2"
+}
+
+# Check if Python 2
+python2_check() {
+  VERSION="$1"
+
+  version_gte "$VERSION" "python-2.7.0" && version_gt "python-3.0.0" "$VERSION"
+}
+
+# Check if Python 3
+python3_check() {
+  VERSION="$1"
+
+  version_gte "$VERSION" "python-3.0.0" && version_gt "python-4.0.0" "$VERSION"
+}
+
+# Check if Python version needs to install SQLite3
+python_sqlite3_check() {
+  VERSION="$1"
+  MIN_PYTHON_3="python-3.5.6"
+  MIN_PYTHON_2="python-2.7.15"
+
+  ( python2_check "$VERSION" && version_gte "$VERSION" "$MIN_PYTHON_2" ) \
+    || ( python3_check "$VERSION" && version_gte "$VERSION" "$MIN_PYTHON_3" )
+}
+
+is_module_available() {
+  # Returns 0 is the specified module exists, otherwise returns 1.
+  # Uses pkgutil rather than pkg_resources or pip's CLI, since pkgutil exists
+  # in the stdlib, and doesn't depend on the choice of package manager.
+  local module_name="${1}"
+  python -c "import sys, pkgutil; sys.exit(0 if pkgutil.find_loader('${module_name}') else 1)"
+}

bin/warnings

@@ -12,16 +12,6 @@ old-platform() {
   fi
 }
 
-pylibmc-missing() {
-  if grep -qi 'fatal error: libmemcached/memcached.h: No such file or directory' "$WARNINGS_LOG"; then
-    echo
-    puts-warn "Hello! There was a problem with your build related to libmemcache."
-    puts-warn "The Python library 'pylibmc' must be explicitly specified in 'requirements.txt' in order to build correctly."
-    puts-warn "Once you do that, everything should work as expected.   -- Much Love, Heroku."
-    mcount 'warnings.libmemcache'
-  fi
-}
-
 scipy-included() {
   if grep -qi 'running setup.py install for scipy' "$WARNINGS_LOG"; then
     echo
@@ -56,11 +46,22 @@ six-included() {
   fi
 }
 
+gdal-missing() {
+  if grep -qi 'Could not find gdal-config' "$WARNINGS_LOG"; then
+    mcount 'warnings.gdal'
+    echo
+    puts-warn "Hello! Package installation failed since the GDAL library was not found."
+    puts-warn "For GDAL, GEOS and PROJ support, use the Geo buildpack alongside the Python buildpack:"
+    puts-warn "https://github.com/heroku/heroku-geo-buildpack"
+    puts-warn "  -- Much Love, Heroku."
+  fi
+}
+
 show-warnings() {
   old-platform
-  pylibmc-missing
   scipy-included
   distribute-included
   six-included
+  gdal-missing
 }
 

buildpack.toml

@@ -0,0 +1,13 @@
+[buildpack]
+name = "Python"
+
+  [publish.Ignore]
+  files = [
+    "test/",
+    ".gitignore",
+    ".dockerignore",
+    ".github/",
+    "Dockerfile",
+    "Pipfile",
+    "Pipfile.lock"
+  ]

builds/README.md

@@ -1,41 +1,80 @@
 # Python Buildpack Binaries
 
-For Cedar-14 stack
+The binaries for this buildpack are built in Docker containers based on the Heroku stack image.
-------------------
 
-To get started with it, create an app on Heroku inside a clone of this repository, and set your S3 config vars:
+## Configuration
 
-    $ heroku create --buildpack https://github.com/heroku/heroku-buildpack-python#not-heroku
+In order to publish binaries AWS credentials must be passed to the build container.
-    $ heroku config:set WORKSPACE_DIR=builds
+If you are testing only the build (ie: `bob build`), these are optional.
-    $ heroku config:set AWS_ACCESS_KEY_ID=<your_aws_key>
-    $ heroku config:set AWS_SECRET_ACCESS_KEY=<your_aws_secret>
-    $ heroku config:set S3_BUCKET=<your_s3_bucket_name>
 
+In addition, unless you are building the official binaries for Heroku (which use the defaults
+specified in each `Dockerfile`), you will need to override `S3_BUCKET` and `S3_PREFIX` to
+match your own S3 bucket/use case.
 
-Then, shell into an instance and run a build by giving the name of the formula inside `builds`:
+If you only need to set AWS credentials, you can do so by setting the environment variables
+`AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` before calling the make commands.
 
-    $ heroku run bash
+For example:
-    Running `bash` attached to terminal... up, run.6880
-    ~ $ bob build runtimes/python-2.7.6
 
-    Fetching dependencies... found 2:
+```bash
-      - libraries/sqlite
+set +o history # Disable bash history
+export AWS_ACCESS_KEY_ID=...
+export AWS_SECRET_ACCESS_KEY=...
+set -o history # Re-enable bash history
+make ...
+```
 
-    Building formula runtimes/python-2.7.6:
+If you need to override the default S3 bucket, or would prefer not to use credentials via
-        === Building Python 2.7.6
+environment variables, then you need to instead use a Docker env file like so:
-        Fetching Python v2.7.6 source...
-        Compiling...
 
-If this works, run `bob deploy` instead of `bob build` to have the result uploaded to S3 for you.
+1. Copy the `builds/dockerenv.default` env file to a location outside the buildpack repository.
+2. Edit the new file, adding at a minimum the values for the variables
+   `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` (see Docker
+   [env-file documentation](https://docs.docker.com/engine/reference/commandline/run/#set-environment-variables--e---env---env-file)).
+3. Pass the path of the file to the make commands using `ENV_FILE`. For example:
 
-To speed things up drastically, it'll usually be a good idea to `heroku run bash --size PX` instead.
+   ```bash
+   make ... ENV_FILE=~/.dockerenv.python-buildpack
+   ```
 
-For Heroku-16 stack
+## Launching an interactive build environment
--------------------
 
-1. Ensure GNU Make and Docker are installed.
+To start an interactive version of the build environment (ideal for development) use the
-2. From the root of the buildpack repository, run: `make buildenv-heroku-16`
+`buildenv` make target, passing in the desired `STACK` name. For example:
-3. Follow the instructions displayed!
 
+```bash
+make buildenv STACK=heroku-18
+```
 
-Enjoy :)
+This will create the builder docker image based on the latest image for that stack, and
+then start a bash shell where you can run `bob build`, `bob deploy`, and so forth.
+
+The `builds/` directory is bind-mounted into the running container, so local build formula
+changes will appear there immediately without the need to rebuild the image.
+
+## Bulk deploying runtimes
+
+When a new Python version is released, binaries have to be generated for multiple stacks.
+To automate this, use the `deploy-runtimes` make target, which will ensure the builder
+image is up to date, and then run `bob deploy` for each runtime-stack combination.
+
+The build formula name(s) are passed using `RUNTIMES`, like so:
+
+```bash
+make deploy-runtimes RUNTIMES='python-X.Y.Z'
+```
+
+By default this will deploy to all supported stacks (see `STACKS` in `Makefile`),
+but this can be overridden using `STACKS`:
+
+```bash
+make deploy-runtimes RUNTIMES='python-X.Y.Z' STACKS='heroku-16 heroku-18'
+```
+
+Multiple runtimes can also be specified (useful for when adding a new stack), like so:
+
+```bash
+make deploy-runtimes RUNTIMES='python-A.B.C python-X.Y.Z' STACKS='heroku-20'
+```
+
+Note: Both `RUNTIMES` and `STACKS` are space delimited.

builds/dockerenv.default

@@ -0,0 +1,8 @@
+# Since no values are specified here, these variables will be read from the environment at run time:
+# https://docs.docker.com/engine/reference/commandline/run/#set-environment-variables--e---env---env-file
+AWS_ACCESS_KEY_ID
+AWS_SECRET_ACCESS_KEY
+
+# Uncomment these if you need to override the default S3 bucket and/or path prefixes.
+# S3_BUCKET
+# S3_PREFIX

builds/heroku-16.Dockerfile

@@ -0,0 +1,20 @@
+FROM heroku/heroku:16-build
+
+ENV WORKSPACE_DIR="/app/builds" \
+    S3_BUCKET="heroku-buildpack-python" \
+    S3_PREFIX="heroku-16/" \
+    STACK="heroku-16"
+
+RUN apt-get update \
+    && DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y \
+        libsqlite3-dev \
+        python3-pip \
+        python3-setuptools \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY requirements.txt /app/
+RUN pip3 install --disable-pip-version-check --no-cache-dir -r /app/requirements.txt
+
+COPY . /app

builds/heroku-18.Dockerfile

@@ -0,0 +1,20 @@
+FROM heroku/heroku:18-build
+
+ENV WORKSPACE_DIR="/app/builds" \
+    S3_BUCKET="heroku-buildpack-python" \
+    S3_PREFIX="heroku-18/" \
+    STACK="heroku-18"
+
+RUN apt-get update \
+    && DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y \
+        libsqlite3-dev \
+        python3-pip \
+        python3-setuptools \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY requirements.txt /app/
+RUN pip3 install --disable-pip-version-check --no-cache-dir -r /app/requirements.txt
+
+COPY . /app

builds/heroku-20.Dockerfile

@@ -0,0 +1,20 @@
+FROM heroku/heroku:20-build
+
+ENV WORKSPACE_DIR="/app/builds" \
+    S3_BUCKET="heroku-buildpack-python" \
+    S3_PREFIX="heroku-20/" \
+    STACK="heroku-20"
+
+RUN apt-get update \
+    && DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y \
+        libsqlite3-dev \
+        python3-pip \
+        python3-setuptools \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY requirements.txt /app/
+RUN pip3 install --disable-pip-version-check --no-cache-dir -r /app/requirements.txt
+
+COPY . /app

builds/libraries/sqlite

@@ -3,7 +3,7 @@
 
 OUT_PREFIX=$1
 
-echo "Building SQLite..."
+echo "Building SQLite…"
 
 
 SOURCE_TARBALL='https://www.sqlite.org/sqlite-autoconf-3070900.tar.gz'
@@ -19,4 +19,4 @@ make install
 
 # Cleanup
 cd ..
-rm -fr sqlite
+rm -rf sqlite

builds/libraries/vendor/gdal

@@ -1,24 +0,0 @@
-#!/usr/bin/env bash
-# Build Path: /app/.heroku/vendor/
-
-OUT_PREFIX=$1
-
-# Use new path, containing autoconf.
-export PATH="/app/.heroku/python/bin/:$PATH"
-hash -r
-
-
-echo "Building gdal..."
-
-VERSION="1.11.5"
-SOURCE_TARBALL="http://download.osgeo.org/gdal/${VERSION}/gdal-${VERSION}.tar.gz"
-
-curl -L $SOURCE_TARBALL | tar zx
-
-pushd "gdal-${VERSION}"
-./configure --prefix=$OUT_PREFIX --enable-static=no  &&
-make
-make install
-
-# Cleanup
-popd

builds/libraries/vendor/geos

@@ -1,23 +0,0 @@
-#!/usr/bin/env bash
-# Build Path: /app/.heroku/vendor/
-
-OUT_PREFIX=$1
-
-# Use new path, containing autoconf.
-export PATH="/app/.heroku/python/bin/:$PATH"
-hash -r
-
-
-echo "Building geos..."
-
-SOURCE_TARBALL='http://download.osgeo.org/geos/geos-3.4.3.tar.bz2'
-
-curl -L $SOURCE_TARBALL | tar xj
-
-cd geos-3.4.3
-./configure --prefix=$OUT_PREFIX --enable-static=no &&
-make
-make install
-
-# Cleanup
-cd ..

builds/libraries/vendor/libffi

@@ -1,28 +0,0 @@
-#!/usr/bin/env bash
-# Build Path: /app/.heroku/vendor/
-
-OUT_PREFIX=$1
-
-# Skip the build for heroku-16.
-if [[ $S3_PREFIX == "heroku-16" ]]; then
-    exit 0
-fi
-
-# Use new path, containing autoconf.
-export PATH="/app/.heroku/python/bin/:$PATH"
-hash -r
-
-
-echo "Building libffi..."
-
-SOURCE_TARBALL='ftp://sourceware.org/pub/libffi/libffi-3.1.tar.gz'
-
-curl -L $SOURCE_TARBALL | tar x
-
-cd libffi-3.1
-./configure --prefix=$OUT_PREFIX --disable-static &&
-make
-make install
-
-# Cleanup
-cd ..

builds/libraries/vendor/libmemcache

@@ -1,45 +0,0 @@
-#!/usr/bin/env bash
-# Build Path: /app/.heroku/vendor/
-
-OUT_PREFIX=$1
-
-# Skip the build for heroku-16.
-if [[ $S3_PREFIX == "heroku-16" ]]; then
-    exit 0
-fi
-
-# fail hard
-set -o pipefail
-# fail harder
-set -eux
-
-DEFAULT_VERSION="1.0.18"
-dep_version=${VERSION:-$DEFAULT_VERSION}
-dep_dirname=libmemcached-${dep_version}
-dep_archive_name=${dep_dirname}.tar.gz
-dep_url=https://launchpad.net/libmemcached/1.0/${dep_version}/+download/${dep_archive_name}
-
-# SASL Support.
-echo "-----> Building cyrus-sasl 2.1.26..."
-
-curl -LO ftp://ftp.cyrusimap.org/cyrus-sasl/cyrus-sasl-2.1.26.tar.gz
-# FTP doesn't play well with piping into tar xz
-tar xzf cyrus-sasl-2.1.26.tar.gz
-
-pushd cyrus-sasl-2.1.26
-./configure --prefix=${OUT_PREFIX} --with-plugindir=${OUT_PREFIX}lib/sasl2 --with-configdir=${OUT_PREFIX}lib/sasl2
-
-make -s -j 9
-make install -s
-popd
-
-echo "-----> Building libmemcached ${dep_version}..."
-
-curl -L ${dep_url} | tar xz
-pushd ${dep_dirname}
-CPPFLAGS=-I${OUT_PREFIX}/include LDFLAGS=-L${OUT_PREFIX}/lib ./configure --prefix=${OUT_PREFIX} --without-memcached
-make -s -j 9
-make install -s
-popd
-
-echo "-----> Done."

builds/libraries/vendor/proj

@@ -1,23 +0,0 @@
-#!/usr/bin/env bash
-# Build Path: /app/.heroku/vendor/
-
-OUT_PREFIX=$1
-
-# Use new path, containing autoconf.
-export PATH="/app/.heroku/python/bin/:$PATH"
-hash -r
-
-
-echo "Building gdal..."
-
-SOURCE_TARBALL='http://download.osgeo.org/proj/proj-4.8.0.tar.gz'
-
-curl -L $SOURCE_TARBALL | tar zx
-
-cd proj-4.8.0
-./configure --prefix=$OUT_PREFIX --enable-static=no &&
-make
-make install
-
-# Cleanup
-cd ..

builds/runtimes/pypy

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# fail hard
+set -o pipefail
+# fail harder
+set -eu
+
+OUT_PREFIX=$1
+
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+dep_name=$(basename $BASH_SOURCE) # this is us
+dep_version=${dep_formula##*"/${dep_name}-"} # "subtract" our name from full version name
+dep_package=${dep_name}2-v${dep_version} # it's always "pypy2-…"
+dep_dirname=${dep_package}-linux64
+dep_archive_name=${dep_dirname}.tar.bz2
+dep_url=https://bitbucket.org/pypy/pypy/downloads/${dep_archive_name}
+
+echo "Building PyPy…"
+
+curl -L "${dep_url}" | tar jx -C "${OUT_PREFIX}" --strip-components 1 # extract to $OUT_PREFIX, drop the first directory level, which is the archive name
+
+ln "$OUT_PREFIX/bin/pypy" "$OUT_PREFIX/bin/python"

builds/runtimes/pypy-5.3.1

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
+source $(dirname $0)/pypy
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.3.1-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.3.1-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python

builds/runtimes/pypy-5.6.0

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
+source $(dirname $0)/pypy
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.6.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.6.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python

builds/runtimes/pypy-5.7.0

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 and heroku-16 stacks, not cedar.
+source $(dirname $0)/pypy
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.7.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.7.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python

builds/runtimes/pypy-5.7.1

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
+source $(dirname $0)/pypy
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.7.1-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.7.1-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python

builds/runtimes/pypy-5.8.0

@@ -2,11 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/pypy
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.8.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.8.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python

builds/runtimes/pypy2.7

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+# fail hard
+set -o pipefail
+# fail harder
+set -eu
+
+OUT_PREFIX=$1
+
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+dep_name=$(basename $BASH_SOURCE) # this is us
+dep_version=${dep_formula##*"/${dep_name}-"} # "subtract" our name from full version name
+dep_package=${dep_name}-v${dep_version} # it's always "pypy2-…"
+dep_dirname=${dep_package}-linux64
+dep_archive_name=${dep_dirname}.tar.bz2
+dep_url="https://downloads.python.org/pypy/${dep_archive_name}"
+
+echo "Building PyPy…"
+echo "${dep_url}"
+
+curl -fL "${dep_url}" | tar jx -C "${OUT_PREFIX}" --strip-components 1 # extract to $OUT_PREFIX, drop the first directory level, which is the archive name
+
+ln "$OUT_PREFIX/bin/pypy" "$OUT_PREFIX/bin/python"

builds/runtimes/pypy2.7-7.2.0

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/pypy2.7

builds/runtimes/pypy2.7-7.3.1

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/pypy2.7

builds/runtimes/pypy2.7-7.3.2

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/pypy2.7

builds/runtimes/pypy3

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# fail hard
+set -o pipefail
+# fail harder
+set -eu
+
+OUT_PREFIX=$1
+
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+dep_name=$(basename $BASH_SOURCE) # this is us
+dep_version=${dep_formula##*"/${dep_name}-"} # "subtract" our name from full version name
+dep_package=${dep_name}${dep_version_prefix:-}-v${dep_version}${dep_version_suffix:-}
+dep_dirname=${dep_package}-linux64
+dep_archive_name=${dep_dirname}.tar.bz2
+dep_url=https://bitbucket.org/pypy/pypy/downloads/${dep_archive_name}
+
+echo "Building PyPy3…"
+
+curl -L "${dep_url}" | tar jx -C "${OUT_PREFIX}" --strip-components 1 # extract to $OUT_PREFIX, drop the first directory level, which is the archive name
+
+ln "$OUT_PREFIX/bin/pypy3" "$OUT_PREFIX/bin/python"

builds/runtimes/pypy3-2.4.0

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
+source $(dirname $0)/pypy3
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3-2.4.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-2.4.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python

builds/runtimes/pypy3-5.5.0

@@ -2,13 +2,7 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
+# version pypy3-5.5.0 is really called pypy3.3-v5.5.0-alpha
-
+dep_version_prefix=".3"
-OUT_PREFIX=$1
+dep_version_suffix="-alpha"
-
+source $(dirname $0)/pypy3
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3.3-v5.5.0-alpha-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-v5.5.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python

builds/runtimes/pypy3-5.7.1

@@ -2,11 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/pypy3
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3-v5.7.1-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-v5.7.1-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python

builds/runtimes/pypy3-5.8.0

@@ -2,11 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/pypy3
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3-v5.8.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-v5.8.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python

builds/runtimes/pypy3.6

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+# fail hard
+set -o pipefail
+# fail harder
+set -eu
+
+OUT_PREFIX=$1
+
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+dep_name=$(basename $BASH_SOURCE) # this is us
+dep_version=${dep_formula##*"/${dep_name}-"} # "subtract" our name from full version name
+dep_package=${dep_name}${dep_version_prefix:-}-v${dep_version}${dep_version_suffix:-}
+dep_dirname=${dep_package}-linux64
+dep_archive_name=${dep_dirname}.tar.bz2
+dep_url="https://downloads.python.org/pypy/${dep_archive_name}"
+
+echo "Building PyPy3…"
+echo "${dep_url}"
+
+curl -fL "${dep_url}" | tar jx -C "${OUT_PREFIX}" --strip-components 1 # extract to $OUT_PREFIX, drop the first directory level, which is the archive name
+
+ln "$OUT_PREFIX/bin/pypy3" "$OUT_PREFIX/bin/python"

builds/runtimes/pypy3.6-7.2.0

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/pypy3.6

builds/runtimes/pypy3.6-7.3.1

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/pypy3.6

builds/runtimes/pypy3.6-7.3.2

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/pypy3.6

builds/runtimes/python-2.7.10

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/python2
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.10/Python-2.7.10.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.10 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install

builds/runtimes/python-2.7.11

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/python2
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.11/Python-2.7.11.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.11 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install

builds/runtimes/python-2.7.12

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/python2
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.12/Python-2.7.12.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.12 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install

builds/runtimes/python-2.7.13

@@ -1,19 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/python2
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.13/Python-2.7.13.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.13 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --enable-unicode=ucs4 --with-ensurepip=no
-make
-make install
-
-# Remove unneeded test directories, similar to the official Docker Python images:
-# https://github.com/docker-library/python
-find "${OUT_PREFIX}" \( -type d -a \( -name test -o -name tests \) \) -exec rm -rf '{}' +

builds/runtimes/python-2.7.14

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.15

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.16

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.17

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.18

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.9

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/python2
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.9/Python-2.7.9.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.9 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install

builds/runtimes/python-3.4.10

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.4.9

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.0

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.1

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.10

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.2

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.5.2/Python-3.5.2.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.5.2 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-# ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.5.3

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.5.3/Python-3.5.3.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.5.3 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-# ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.5.4

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.5

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.6

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.7

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.9

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.0

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.6.0/Python-3.6.0.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.6.0 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.6.1

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.6.1/Python-3.6.1.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.6.1 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.6.10

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.11

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.12

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.2

@@ -1,21 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
+source $(dirname $0)/python3
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.6.2/Python-3.6.2.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.6.2 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-# Remove unneeded test directories, similar to the official Docker Python images:
-# https://github.com/docker-library/python
-find "${OUT_PREFIX}" \( -type d -a \( -name test -o -name tests \) \) -exec rm -rf '{}' +
-
-ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python

builds/runtimes/python-3.6.3

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.4

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.5

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.6

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.7

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.8

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.9

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3