changelog

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>
Pipenv improvements (#474 )
2026-06-05 23:10:16 +00:00 · 2017-09-24 23:20:01 -04:00 · 2017-09-24 23:18:22 -04:00 · 2017-09-08 12:36:53 -04:00 · 2017-09-08 12:28:05 -04:00 · 2017-09-08 12:20:14 -04:00
60 changed files with 879 additions and 404 deletions
@@ -0,0 +1 @@
+.git/
@@ -1,3 +1,5 @@
 *.pyc
 site
 .DS_Store
+
+/.envrc
@@ -1,9 +1,23 @@
 language: bash
-sudo: required
-services:
-  - docker
-# install: docker pull heroku/cedar:14
-script: ./tests.sh
-env:
-  - STACK=heroku-16
-  - STACK=cedar-14
+dist: trusty
+jobs:
+  include:
+    - stage: "Bash linting (shellcheck)"
+      sudo: false
+      addons:
+        apt:
+          sources:
+          - debian-sid    # Grab shellcheck from the Debian repo (o_O)
+          packages:
+          - shellcheck
+      script: make check
+
+    - stage: "Stack Tests"
+      services: docker
+      env: STACK=heroku-16
+      script: ./tests.sh
+
+    - stage: "Stack Tests"
+      services: docker
+      env: STACK=cedar-14
+      script: ./tests.sh
@@ -1,5 +1,108 @@
 # Python Buildpack Changelog

+# 118
+
+Improvements to Pipenv support.
+
+# 117
+
+Bug fix.
+
+# 116
+
+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
+
+Revert a pull request.
+
+- No longer using `sub_env` for `pip install` step.
+
+# 114
+
+- Bugfixes.
+
+Blacklisting `PYTHONHOME` and `PYTHONPATH` for older apps. Upgrades to nltk support.
+
+# 113
+
+Updates to Pipenv support.
+
+# 112
+
+Bugfix.
+
+- Fixed grep output bug.
+
+# 111
+
+Linting, bugfixes.
+
+# 110
+
+Update default Python to 3.6.2.
+
+# 109
+
+Update Default Python to 3.6.1, bugfixes.
+
+- Fixed automatic pip uninstall of dependencies removed from requirements.txt.
+
+# 108
+
+Fix output for collectstatic step.
+
+# 107
+
+Bugfix for C dependency installation.
+
+# 106
+
+ 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
+
+ Improvements to output messaging.
+
+# 104
+
+General improvements.
+
+- Fix for Heroku CI.
+- Use `pkg_resources` to check if a distribution is installed instead of
+  parsing `requirements.txt`. ([#395][395])
+
+[395]: https://github.com/heroku/heroku-buildpack-python/pull/395
+
+## 103
+
+Bug fixes and improvements.
+
+- Fix for Pipenv.
+- Fix for Heroku CI.
+- 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).
+- Restore the build cache prior to running bin/pre_compile.
+
+## 102
+
+Buildpack code cleanup.
+
+- Improved messaging around NLTK.
+
+## 101
+
+Updated setuptools installation method.
+
+- Improved pipenv support.
+
 ## 100

 Preliminary pipenv support.
@@ -1,11 +1,13 @@
 FROM heroku/heroku:16-build

 WORKDIR /app
-ENV WORKSPACE_DIR=/app/builds
+ENV WORKSPACE_DIR="/app/builds" \
+    S3_BUCKET="lang-python" \
+    S3_PREFIX="heroku-16/"

-RUN apt-get update && apt-get install -y python-pip
+RUN apt-get update && apt-get install -y python-pip && rm -rf /var/lib/apt/lists/*

-# Install bob-builder application
-RUN pip install bob-builder==0.0.5
+COPY requirements.txt /app/
+RUN pip install --disable-pip-version-check --no-cache-dir -r /app/requirements.txt

-COPY . /app
+COPY . /app
@@ -1,6 +1,6 @@
 MIT License:

-Copyright (C) 2016 Heroku, Inc.
+Copyright (C) 2017 Heroku, Inc.

 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:

@@ -1,7 +1,12 @@
 # These targets are not files
 .PHONY: tests

-test: test-cedar-14
+test: test-heroku-16
+
+check:
+	@shellcheck -x bin/compile bin/detect bin/release bin/test-compile bin/utils bin/warnings
+	@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/hooks/*

 test-cedar-14:
 	@echo "Running tests in docker (cedar-14)..."
@@ -13,7 +18,20 @@ test-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 .
+	@echo
+	@echo "Usage..."
+	@echo
+	@echo "  $$ export AWS_ACCESS_KEY_ID=foo AWS_SECRET_ACCESS_KEY=bar  # Optional unless deploying"
+	@echo "  $$ bob build runtimes/python-2.7.13"
+	@echo "  $$ bob deploy runtimes/python-2.7.13"
+	@echo
+	@docker run -it --rm python-buildenv-heroku-16
+
 tools:
 	git clone https://github.com/kennethreitz/pip-pop.git
 	mv pip-pop/bin/* vendor/pip-pop/
-	rm -fr pip-pop
+	rm -fr pip-pop
@@ -0,0 +1,137 @@
+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
+---------------
+
+Copyright © 2007 Free Software Foundation, Inc. <http://fsf.org/>
+
+Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
+
+This version of the GNU Lesser General Public License incorporates the terms and conditions of version 3 of the GNU General Public License, supplemented by the additional permissions listed below.
+
+0. Additional Definitions.
+
+As used herein, “this License” refers to version 3 of the GNU Lesser General Public License, and the “GNU GPL” refers to version 3 of the GNU General Public License.
+
+“The Library” refers to a covered work governed by this License, other than an Application or a Combined Work as defined below.
+
+An “Application” is any work that makes use of an interface provided by the Library, but which is not otherwise based on the Library. Defining a subclass of a class defined by the Library is deemed a mode of using an interface provided by the Library.
+
+A “Combined Work” is a work produced by combining or linking an Application with the Library. The particular version of the Library with which the Combined Work was made is also called the “Linked Version”.
+
+The “Minimal Corresponding Source” for a Combined Work means the Corresponding Source for the Combined Work, excluding any source code for portions of the Combined Work that, considered in isolation, are based on the Application, and not on the Linked Version.
+
+The “Corresponding Application Code” for a Combined Work means the object code and/or source code for the Application, including any data and utility programs needed for reproducing the Combined Work from the Application, but excluding the System Libraries of the Combined Work.
+
+1. Exception to Section 3 of the GNU GPL.
+
+You may convey a covered work under sections 3 and 4 of this License without being bound by section 3 of the GNU GPL.
+
+2. Conveying Modified Versions.
+
+If you modify a copy of the Library, and, in your modifications, a facility refers to a function or data to be supplied by an Application that uses the facility (other than as an argument passed when the facility is invoked), then you may convey a copy of the modified version:
+
+a) under this License, provided that you make a good faith effort to ensure that, in the event an Application does not supply the function or data, the facility still operates, and performs whatever part of its purpose remains meaningful, or
+b) under the GNU GPL, with none of the additional permissions of this License applicable to that copy.
+3. Object Code Incorporating Material from Library Header Files.
+
+The object code form of an Application may incorporate material from a header file that is part of the Library. You may convey such object code under terms of your choice, provided that, if the incorporated material is not limited to numerical parameters, data structure layouts and accessors, or small macros, inline functions and templates (ten or fewer lines in length), you do both of the following:
+
+a) Give prominent notice with each copy of the object code that the Library is used in it and that the Library and its use are covered by this License.
+b) Accompany the object code with a copy of the GNU GPL and this license document.
+4. Combined Works.
+
+You may convey a Combined Work under terms of your choice that, taken together, effectively do not restrict modification of the portions of the Library contained in the Combined Work and reverse engineering for debugging such modifications, if you also do each of the following:
+
+a) Give prominent notice with each copy of the Combined Work that the Library is used in it and that the Library and its use are covered by this License.
+b) Accompany the Combined Work with a copy of the GNU GPL and this license document.
+c) For a Combined Work that displays copyright notices during execution, include the copyright notice for the Library among these notices, as well as a reference directing the user to the copies of the GNU GPL and this license document.
+d) Do one of the following:
+0) Convey the Minimal Corresponding Source under the terms of this License, and the Corresponding Application Code in a form suitable for, and under terms that permit, the user to recombine or relink the Application with a modified version of the Linked Version to produce a modified Combined Work, in the manner specified by section 6 of the GNU GPL for conveying Corresponding Source.
+1) Use a suitable shared library mechanism for linking with the Library. A suitable mechanism is one that (a) uses at run time a copy of the Library already present on the user's computer system, and (b) will operate properly with a modified version of the Library that is interface-compatible with the Linked Version.
+e) Provide Installation Information, but only if you would otherwise be required to provide such information under section 6 of the GNU GPL, and only to the extent that such information is necessary to install and execute a modified version of the Combined Work produced by recombining or relinking the Application with a modified version of the Linked Version. (If you use option 4d0, the Installation Information must accompany the Minimal Corresponding Source and Corresponding Application Code. If you use option 4d1, you must provide the Installation Information in the manner specified by section 6 of the GNU GPL for conveying Corresponding Source.)
+5. Combined Libraries.
+
+You may place library facilities that are a work based on the Library side by side in a single library together with other library facilities that are not Applications and are not covered by this License, and convey such a combined library under terms of your choice, if you do both of the following:
+
+a) Accompany the combined library with a copy of the same work based on the Library, uncombined with any other library facilities, conveyed under the terms of this License.
+b) Give prominent notice with the combined library that part of it is a work based on the Library, and explaining where to find the accompanying uncombined form of the same work.
+6. Revised Versions of the GNU Lesser General Public License.
+
+The Free Software Foundation may publish revised and/or new versions of the GNU Lesser General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
+
+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.
@@ -4,11 +4,11 @@

 [![Build Status](https://travis-ci.org/heroku/heroku-buildpack-python.svg?branch=master)](https://travis-ci.org/heroku/heroku-buildpack-python)

-This is the official [Heroku buildpack](https://devcenter.heroku.com/articles/buildpacks) for Python apps, powered by [pip](https://pip.pypa.io/) and other excellent software.
+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.

 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.

-Some Python packages with obscure C dependencies (e.g. scipy) are [not compatible](https://devcenter.heroku.com/articles/python-c-deps). 
+Some Python packages with obscure C dependencies are [not compatible](https://devcenter.heroku.com/articles/python-c-deps).

 See it in Action
 ----------------
@@ -16,24 +16,22 @@ See it in Action
 Deploying a Python application couldn't be easier:

    $ ls
-    Procfile  requirements.txt  web.py
+    Pipfile		Procfile	web.py

    $ heroku create --buildpack heroku/python

    $ git push heroku master
    ...
    -----> Python app detected
-    -----> Installing python-2.7.13
-         $ pip install -r requirements.txt
-           Collecting requests (from -r requirements.txt (line 1))
-             Downloading requests-2.12.4-py2.py3-none-any.whl (576KB)
-           Installing collected packages: requests
-           Successfully installed requests-2.12.4
-           
+    -----> Installing python-3.6.2
+    -----> Installing pip
+    -----> Installing requirements with latest pipenv...
+           ...
+           Installing dependencies from Pipfile...
    -----> Discovering process types
           Procfile declares types -> (none)

-A `requirements.txt` file must be present at the root of your application's repository.
+A `Pipfile` or `requirements.txt` must be present at the root of your application's repository.

 You can also specify the latest production release of this buildpack for upcoming builds of an existing application:

@@ -46,11 +44,11 @@ Specify a Python Runtime
 Specific versions of the Python runtime can be specified with a `runtime.txt` file:

    $ cat runtime.txt
-    python-3.6.0
+    python-2.7.13

 Runtime options include:

+- `python-3.6.2`
 - `python-2.7.13`
- `python-3.6.0`
- `pypy-5.6.0` (unsupported, experimental)
- `pypy3-5.5.0` (unsupported, experimental)
+- `pypy-5.7.1` (unsupported, experimental)
+- `pypy3-5.5.1` (unsupported, experimental)
@@ -15,37 +15,38 @@
 # Fail fast and fail hard.
 set -eo pipefail

+# Standard Library.
+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.
 export PATH=:/usr/local/bin:$PATH

 # Paths.
-BIN_DIR=$(cd $(dirname $0); pwd) # absolute path
-ROOT_DIR=$(dirname $BIN_DIR)
+BIN_DIR=$(cd "$(dirname "$0")"; pwd) # absolute path
+ROOT_DIR=$(dirname "$BIN_DIR")
 BUILD_DIR=$1
 CACHE_DIR=$2
 ENV_DIR=$3

+export BUILD_DIR CACHE_DIR ENV_DIR
+
 # Python defaults
-DEFAULT_PYTHON_VERSION="python-2.7.13"
+DEFAULT_PYTHON_VERSION="python-3.6.2"
 DEFAULT_PYTHON_STACK="cedar-14"
-PYTHON_EXE="/app/.heroku/python/bin/python"
-PIP_VERSION="9.0.1"
-SETUPTOOLS_VERSION="32.1.0"
+PIP_UPDATE="9.0.1"
+
+export DEFAULT_PYTHON_VERSION DEFAULT_PYTHON_STACK PIP_UPDATE

 # Common Problem Warnings
-export WARNINGS_LOG=$(mktemp)
+WARNINGS_LOG=$(mktemp)
+export WARNINGS_LOG
 export RECOMMENDED_PYTHON_VERSION=$DEFAULT_PYTHON_VERSION

-# Setup bpwatch
-export PATH=$PATH:$ROOT_DIR/vendor/:$ROOT_DIR/vendor/bpwatch
-LOGPLEX_KEY="t.b90d9d29-5388-4908-9737-b4576af1d4ce"
-export BPWATCH_STORE_PATH=$CACHE_DIR/bpwatch.json
-BUILDPACK_VERSION=v28
-
-# Setup pip-pop (pip-diff)
-export PATH=$PATH:$ROOT_DIR/vendor/pip-pop
+# Setup vendored tools and pip-pop (pip-diff)
+export PATH=$PATH:$ROOT_DIR/vendor/:$ROOT_DIR/vendor/pip-pop

 # Support Anvil Build_IDs
 [ ! "$SLUG_ID" ] && SLUG_ID="defaultslug"
@@ -54,20 +55,16 @@ export PATH=$PATH:$ROOT_DIR/vendor/pip-pop

 # Sanitizing environment variables.
 unset GIT_DIR PYTHONHOME PYTHONPATH
-unset RECEIVE_DATA RUN_KEY BUILD_INFO DEPLOY LOG_TOKEN DYNO
+unset RECEIVE_DATA RUN_KEY BUILD_INFO DEPLOY LOG_TOKEN
 unset CYTOKINE_LOG_FILE GEM_PATH

-# Setup buildpack instrumentation.
-bpwatch init $LOGPLEX_KEY
-bpwatch build python $BUILDPACK_VERSION $REQUEST_ID
-
-bpwatch start compile
-
 # Syntax sugar.
-source $BIN_DIR/utils
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"

 # Import collection of warnings.
-source $BIN_DIR/warnings
+# shellcheck source=bin/warnings
+source "$BIN_DIR/warnings"

 # we need to put a bunch of symlinks in there later
 mkdir -p /app/.heroku
@@ -76,6 +73,7 @@ mkdir -p /app/.heroku
 PROFILE_PATH="$BUILD_DIR/.profile.d/python.sh"
 EXPORT_PATH="$BIN_DIR/../export"
 GUNICORN_PROFILE_PATH="$BUILD_DIR/.profile.d/python.gunicorn.sh"
+WEB_CONCURRENCY_PROFILE_PATH="$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
@@ -91,7 +89,7 @@ export LD_LIBRARY_PATH=/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LD_LIBRA
 export PKG_CONFIG_PATH=/app/.heroku/vendor/lib/pkg-config:/app/.heroku/python/lib/pkg-config:$PKG_CONFIG_PATH

 # Switch to the repo's context.
-cd $BUILD_DIR
+cd "$BUILD_DIR"

 # Warn for lack of Procfile.
 if [[ ! -f Procfile ]]; then
@@ -99,67 +97,67 @@ if [[ ! -f Procfile ]]; then
  puts-warn 'Learn more: https://devcenter.heroku.com/articles/procfile'
 fi

+# Prepare the cache.
+mkdir -p "$CACHE_DIR"
+
+# Restore old artifacts from the cache.
+mkdir -p .heroku
+
+cp -R "$CACHE_DIR/.heroku/python" .heroku/ &> /dev/null || true
+cp -R "$CACHE_DIR/.heroku/python-stack" .heroku/ &> /dev/null || true
+cp -R "$CACHE_DIR/.heroku/python-version" .heroku/ &> /dev/null || true
+cp -R "$CACHE_DIR/.heroku/vendor" .heroku/ &> /dev/null || true
+if [[ -d "$CACHE_DIR/.heroku/src" ]]; then
+  cp -R "$CACHE_DIR/.heroku/src" .heroku/ &> /dev/null || true
+fi
+
 # Experimental pre_compile hook.
-bpwatch start pre_compile
-  source $BIN_DIR/steps/hooks/pre_compile
-bpwatch stop pre_compile
+# shellcheck source=bin/steps/hooks/pre_compile
+source "$BIN_DIR/steps/hooks/pre_compile"

 # Sticky runtimes.
-if [ -f $CACHE_DIR/.heroku/python-version ]; then
-  DEFAULT_PYTHON_VERSION=$(cat $CACHE_DIR/.heroku/python-version)
+if [ -f "$CACHE_DIR/.heroku/python-version" ]; then
+  DEFAULT_PYTHON_VERSION=$(cat "$CACHE_DIR/.heroku/python-version")
 fi

 # Stack fallback for non-declared caches.
-if [ -f $CACHE_DIR/.heroku/python-stack ]; then
-  CACHED_PYTHON_STACK=$(cat $CACHE_DIR/.heroku/python-stack)
+if [ -f "$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.
-source $BIN_DIR/steps/pipenv-python-version
+# shellcheck source=bin/steps/pipenv-python-version
+source "$BIN_DIR/steps/pipenv-python-version"

 # If no runtime given, assume default version.
 if [ ! -f runtime.txt ]; then
-  echo $DEFAULT_PYTHON_VERSION > runtime.txt
+  echo "$DEFAULT_PYTHON_VERSION" > runtime.txt
 fi

-# Prepare the cache.
-mkdir -p $CACHE_DIR
-
-# Restore old artifacts from the cache.
-bpwatch start restore_cache
-    mkdir -p .heroku
-
-    cp -R $CACHE_DIR/.heroku/python .heroku/ &> /dev/null || true
-    cp -R $CACHE_DIR/.heroku/python-stack .heroku/ &> /dev/null || true
-    cp -R $CACHE_DIR/.heroku/python-version .heroku/ &> /dev/null || true
-    cp -R $CACHE_DIR/.heroku/vendor .heroku/ &> /dev/null || true
-    if [[ -d $CACHE_DIR/.heroku/src ]]; then
-      cp -R $CACHE_DIR/.heroku/src .heroku/ &> /dev/null || true
-    fi
-
-bpwatch stop restore_cache
-
-mkdir -p $(dirname $PROFILE_PATH)
+mkdir -p "$(dirname "$PROFILE_PATH")"
 mkdir -p /app/.heroku/src

 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
-    ln -nsf $BUILD_DIR/.heroku/python /app/.heroku/python
-    ln -nsf $BUILD_DIR/.heroku/vendor /app/.heroku/vendor
+    ln -nsf "$BUILD_DIR/.heroku/python" /app/.heroku/python
+    ln -nsf "$BUILD_DIR/.heroku/vendor" /app/.heroku/vendor
    # Note: .heroku/src is copied in later.
 fi

 # Install Python.
-source $BIN_DIR/steps/python
-
-# Sanity check for setuptools/distribute.
-source $BIN_DIR/steps/setuptools
+let start=$(nowms)
+# shellcheck source=bin/steps/python
+source "$BIN_DIR/steps/python"
+mtime "python.install.time" "${start}"

 # Pipenv support.
-source $BIN_DIR/steps/pipenv
+# shellcheck source=bin/steps/pipenv
+source "$BIN_DIR/steps/pipenv"

 # If no requirements.txt file given, assume `setup.py develop` is intended.
 if [ ! -f requirements.txt ] && [ ! -f Pipfile ]; then
@@ -167,79 +165,101 @@ if [ ! -f requirements.txt ] && [ ! -f Pipfile ]; then
 fi

 # Fix egg-links.
-source $BIN_DIR/steps/eggpath-fix
+# shellcheck source=bin/steps/eggpath-fix
+source "$BIN_DIR/steps/eggpath-fix"

 # Mercurial support.
-source $BIN_DIR/steps/mercurial
+# shellcheck source=bin/steps/mercurial
+source "$BIN_DIR/steps/mercurial"

 # Pylibmc support.
-source $BIN_DIR/steps/pylibmc
+# shellcheck source=bin/steps/pylibmc
+source "$BIN_DIR/steps/pylibmc"

 # Libffi support.
-source $BIN_DIR/steps/cryptography
+# shellcheck source=bin/steps/cryptography
+source "$BIN_DIR/steps/cryptography"

 # Support for Geo libraries.
-sub-env $BIN_DIR/steps/geo-libs
+# shellcheck source=bin/steps/geo-libs
+sub_env "$BIN_DIR/steps/geo-libs"

 # GDAL support.
-source $BIN_DIR/steps/gdal
-
-# Install dependencies with Pip (where the magic happens).
-source $BIN_DIR/steps/pip-install
+# shellcheck source=bin/steps/gdal
+source "$BIN_DIR/steps/gdal"

 # Uninstall removed dependencies with Pip.
-source $BIN_DIR/steps/pip-uninstall
+let start=$(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.
-sub-env $BIN_DIR/steps/nltk
+let start=$(nowms)
+sub_env "$BIN_DIR/steps/nltk"
+mtime "nltk.download.time" "${start}"

 # Support for pip install -e.
-rm -fr $BUILD_DIR/.heroku/src
-deep-cp /app/.heroku/src $BUILD_DIR/.heroku/src
+# In CI, $BUILD_DIR is /app.
+if [[ ! "$BUILD_DIR" == "/app" ]]; then
+  rm -fr "$BUILD_DIR/.heroku/src"
+  deep-cp /app/.heroku/src "$BUILD_DIR/.heroku/src"
+fi
+

 # Django collectstatic support.
-sub-env $BIN_DIR/steps/collectstatic
+let start=$(nowms)
+sub_env "$BIN_DIR/steps/collectstatic"
+mtime "collectstatic.time" "${start}"

 # Create .profile script for application runtime environment variables.
-set-env PATH '$HOME/.heroku/python/bin:$PATH'
-set-env PYTHONUNBUFFERED true
-set-env PYTHONHOME /app/.heroku/python
-set-env LIBRARY_PATH '/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LIBRARY_PATH'
-set-env LD_LIBRARY_PATH '/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LD_LIBRARY_PATH'
-set-default-env LANG en_US.UTF-8
-set-default-env PYTHONHASHSEED random
-set-default-env PYTHONPATH /app/
+set_env PATH "\$HOME/.heroku/python/bin:\$PATH"
+set_env PYTHONUNBUFFERED true
+set_env PYTHONHOME /app/.heroku/python
+
+set_env LIBRARY_PATH "/app/.heroku/vendor/lib:/app/.heroku/python/lib:\$LIBRARY_PATH"
+set_env LD_LIBRARY_PATH "/app/.heroku/vendor/lib:/app/.heroku/python/lib:\$LD_LIBRARY_PATH"
+
+set_default_env LANG en_US.UTF-8
+set_default_env PYTHONHASHSEED random
+set_default_env PYTHONPATH /app/

 # Install sane-default script for $WEB_CONCURRENCY and $FORWARDED_ALLOW_IPS.
-cp $ROOT_DIR/vendor/python.gunicorn.sh $GUNICORN_PROFILE_PATH
+cp "$ROOT_DIR/vendor/WEB_CONCURRENCY.sh" "$WEB_CONCURRENCY_PROFILE_PATH"
+cp "$ROOT_DIR/vendor/python.gunicorn.sh" "$GUNICORN_PROFILE_PATH"
+

 # Experimental post_compile hook.
-bpwatch start post_compile
-  source $BIN_DIR/steps/hooks/post_compile
-bpwatch stop post_compile
+# shellcheck source=bin/steps/hooks/post_compile
+source "$BIN_DIR/steps/hooks/post_compile"

 # Fix egg-links, again.
-source $BIN_DIR/steps/eggpath-fix2
+# shellcheck source=bin/steps/eggpath-fix2
+source "$BIN_DIR/steps/eggpath-fix2"

 # Store new artifacts in cache.
-bpwatch start dump_cache

-  rm -rf $CACHE_DIR/.heroku/python
-  rm -rf $CACHE_DIR/.heroku/python-version
-  rm -rf $CACHE_DIR/.heroku/python-stack
-  rm -rf $CACHE_DIR/.heroku/vendor
-  rm -rf $CACHE_DIR/.heroku/src
+rm -rf "$CACHE_DIR/.heroku/python"
+rm -rf "$CACHE_DIR/.heroku/python-version"
+rm -rf "$CACHE_DIR/.heroku/python-stack"
+rm -rf "$CACHE_DIR/.heroku/vendor"
+rm -rf "$CACHE_DIR/.heroku/src"

-  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 $CACHE_DIR/.heroku/ &> /dev/null || true
-  fi
+mkdir -p "$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

-bpwatch stop dump_cache
-
-# Fin.
-bpwatch stop compile
+# Measure the size of the Python installation.
+# shellcheck disable=SC2119
+mmeasure 'python.size' "$(measure-size)"
@@ -15,7 +15,7 @@
 BUILD_DIR=$1

 # Exit early if app is clearly not Python.
-if [ ! -f $BUILD_DIR/requirements.txt ] && [ ! -f $BUILD_DIR/setup.py ] && [ ! -f $BUILD_DIR/Pipfile ]; then
+if [ ! -f "$BUILD_DIR/requirements.txt" ] && [ ! -f "$BUILD_DIR/setup.py" ] && [ ! -f "$BUILD_DIR/Pipfile" ]; then
  exit 1
 fi

@@ -1,10 +1,9 @@
 #!/usr/bin/env bash
 # bin/release <build-dir>

-BIN_DIR=$(cd $(dirname $0); pwd) # absolute path
 BUILD_DIR=$1

-MANAGE_FILE=$(cd $BUILD_DIR && find . -maxdepth 3 -type f -name 'manage.py' | head -1)
+MANAGE_FILE=$(cd "$BUILD_DIR" && find . -maxdepth 3 -type f -name 'manage.py' | head -1)
 MANAGE_FILE=${MANAGE_FILE:2}

 cat <<EOF
@@ -10,6 +10,7 @@
 #   - $DISABLE_COLLECTSTATIC: disables this functionality.
 #   - $DEBUG_COLLECTSTATIC: upon failure, print out environment variables.

+# shellcheck source=bin/utils
 source $BIN_DIR/utils

 # Location of 'manage.py', if it exists.
@@ -20,23 +21,22 @@ MANAGE_FILE=${MANAGE_FILE:-fakepath}
 [ -f .heroku/collectstatic_disabled ] && DISABLE_COLLECTSTATIC=1

 # Ensure that Django is explicitly specified in requirements.txt
-pip-grep -s requirements.txt django Django && DJANGO_INSTALLED=1
+sp-grep -s django && DJANGO_INSTALLED=1

-bpwatch start collectstatic  # metrics collection

 if [ ! "$DISABLE_COLLECTSTATIC" ] && [ -f "$MANAGE_FILE" ] && [ "$DJANGO_INSTALLED" ]; then
    set +e

-    puts-cmd "python $MANAGE_FILE collectstatic --noinput"
+    puts-step "$ 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
+    python "$MANAGE_FILE" collectstatic --noinput --traceback 2>&1 | sed '/^Post-processed/d;/^Copying/d;/^$/d' | indent
    COLLECTSTATIC_STATUS="${PIPESTATUS[0]}"

    set -e

    # Display a warning if collectstatic failed.
-    [ $COLLECTSTATIC_STATUS -ne 0 ] && {
+    [ "$COLLECTSTATIC_STATUS" -ne 0 ] && {

        echo
        echo " !     Error while running '$ python $MANAGE_FILE collectstatic --noinput'."
@@ -63,5 +63,3 @@ if [ ! "$DISABLE_COLLECTSTATIC" ] && [ -f "$MANAGE_FILE" ] && [ "$DJANGO_INSTALL

    echo
 fi
-
-bpwatch stop collectstatic  # metrics collection
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash

-# This script serves as the Cryptography build step of the
+# This script serves as the cffi build step of the
 # [**Python Buildpack**](https://github.com/heroku/heroku-buildpack-python)
 # compiler.
 #
@@ -9,15 +9,19 @@
 #
 # 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.
-source $BIN_DIR/utils
-
-bpwatch start libffi_install
+# shellcheck source=bin/utils
+source "$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
@@ -26,10 +30,9 @@ if (pip-grep -s requirements.txt argon2-cffi bcrypt cffi cryptography django[arg
    echo "-----> Noticed cffi. Bootstrapping libffi."
    mkdir -p .heroku/vendor
    # Download and extract libffi into target vendor directory.
-    curl $VENDORED_LIBFFI -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_LIBFFI" -s | tar zxv -C .heroku/vendor &> /dev/null
  fi

-  export LIBFFI=$(pwd)/vendor
+  LIBFFI=$(pwd)/vendor
+  export LIBFFI
 fi
-
-bpwatch stop libffi_install
@@ -1,3 +1,5 @@
+#!/usr/bin/env bash
+
 set +e
 # delete any existing egg links, to uninstall exisisting installations.
 find .heroku/python/lib/python*/site-packages/ -name "*.egg-link" -delete 2> /dev/null
@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 set +e
 # rewrite build dir in egg links to /app so things are found at runtime
 find .heroku/python/lib/python*/site-packages/ -name "*.pth" -print0 2> /dev/null | xargs -r -0 -n 1 sed -i -e "s#$(pwd)#/app#" &> /dev/null
@@ -15,9 +15,8 @@ VENDORED_GDAL="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/gdal
 PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"

 # Syntax sugar.
-source $BIN_DIR/utils
-
-bpwatch start gdal_install
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"

 # If GDAL exists within requirements, use vendored gdal.
 if (pip-grep -s requirements.txt GDAL gdal pygdal &> /dev/null) then
@@ -26,10 +25,10 @@ if (pip-grep -s requirements.txt GDAL gdal pygdal &> /dev/null) then
    echo "-----> Noticed GDAL. Bootstrapping gdal."
    mkdir -p .heroku/vendor
    # Download and extract cryptography into target vendor directory.
-    curl $VENDORED_GDAL -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_GDAL" -s | tar zxv -C .heroku/vendor &> /dev/null
  fi

-  export GDAL=$(pwd)/vendor
+  GDAL=$(pwd)/vendor
+  export GDAL
 fi

-bpwatch stop gdal_install
@@ -17,9 +17,8 @@ VENDORED_PROJ="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/proj
 PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"

 # Syntax sugar.
-source $BIN_DIR/utils
-
-bpwatch start geo_libs_install
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"

 # If GDAL exists within requirements, use vendored gdal.
 if [[ "$BUILD_WITH_GEO_LIBRARIES" ]]; then
@@ -28,12 +27,18 @@ if [[ "$BUILD_WITH_GEO_LIBRARIES" ]]; 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 $VENDORED_PROJ -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$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
+
+    # Copy libjasper from build image to slug.
+    if [[ "$STACK" == "heroku-16" ]]; then
+      cp /usr/lib/x86_64-linux-gnu/libjasper.so* ".heroku/vendor/lib/."
+    fi
+
  fi

-  export GDAL=$(pwd)/vendor
+  GDAL=$(pwd)/vendor
+  export GDAL
 fi

-bpwatch stop geo_libs_install
@@ -3,5 +3,5 @@
 if [ -f bin/post_compile ]; then
    echo "-----> Running post-compile hook"
    chmod +x bin/post_compile
-    sub-env bin/post_compile
+    sub_env bin/post_compile
 fi
@@ -3,5 +3,5 @@
 if [ -f bin/pre_compile ]; then
    echo "-----> Running pre-compile hook"
    chmod +x bin/pre_compile
-    sub-env bin/pre_compile
+    sub_env bin/pre_compile
 fi
@@ -1,6 +1,6 @@
+#!/usr/bin/env bash
+
 # Install Mercurial if it appears to be required.
 if (grep -Fiq "hg+" requirements.txt) then
-  bpwatch start mercurial_install
    /app/.heroku/python/bin/pip install  mercurial | cleanup | indent
-  bpwatch stop mercurial_install
 fi
@@ -10,24 +10,25 @@
 # This script is invoked by [`bin/compile`](/).

 # Syntax sugar.
-source $BIN_DIR/utils
-
-bpwatch start nltk_download
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"

 # Check that nltk was installed by pip, otherwise obviously not needed
-python -m nltk.downloader -h >/dev/null 2>&1
-if [ $? -eq 0 ]; then
+if sp-grep -s nltk; then
    puts-step "Downloading NLTK corpora..."
+
    nltk_packages_definition="$BUILD_DIR/nltk.txt"
+
    if [ -f "$nltk_packages_definition" ]; then
-        nltk_packages=$(tr "\n" " " < "$nltk_packages_definition")
-        puts-step "Downloading NLTK packages: $nltk_packages"
-        python -m nltk.downloader -d $BUILD_DIR/.heroku/python/nltk_data $nltk_packages  | indent
-        set-env NLTK_DATA "/app/.heroku/python/nltk_data"
+
+        readarray -t nltk_packages < "$nltk_packages_definition"
+        puts-step "Downloading NLTK packages: ${nltk_packages[*]}"
+
+        python -m nltk.downloader -d "$BUILD_DIR/.heroku/python/nltk_data" "${nltk_packages[@]}" | indent
+        set_env NLTK_DATA "/app/.heroku/python/nltk_data"
+
    else
-        puts-warn "nltk.txt not found, not downloading any corpora"
+        puts-warn "'nltk.txt' not found, not downloading any corpora"
+        puts-warn "Learn more: https://devcenter.heroku.com/articles/python-nltk"
    fi
 fi
-
-
-bpwatch stop nltk_download
@@ -1,26 +1,26 @@
-# Install dependencies with Pip.
-puts-step "Installing requirements with pip"
+#!/usr/bin/env bash

-[ ! "$FRESH_PYTHON" ] && bpwatch start pip_install
-[ "$FRESH_PYTHON" ] && bpwatch start pip_install_first
+if [ ! "$SKIP_PIP_INSTALL" ]; then

-set +e
-/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
+    # Install dependencies with Pip.
+    puts-step "Installing requirements with pip"

-show-warnings
+    set +e

-if [[ ! $PIP_STATUS -eq 0 ]]; then
-    exit 1
+    /app/.heroku/python/bin/pip install -r "$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
+
+    show-warnings
+
+    if [[ ! $PIP_STATUS -eq 0 ]]; then
+        exit 1
+    fi
+
+
+    # Smart Requirements handling
+    cp requirements.txt .heroku/python/requirements-declared.txt
+    /app/.heroku/python/bin/pip freeze --disable-pip-version-check > .heroku/python/requirements-installed.txt
+
+    echo
 fi
-
-
-# Smart Requirements handling
-cp requirements.txt .heroku/python/requirements-declared.txt
-/app/.heroku/python/bin/pip freeze --disable-pip-version-check > .heroku/python/requirements-installed.txt
-
-[ ! "$FRESH_PYTHON" ] && bpwatch stop pip_install
-[ "$FRESH_PYTHON" ] && bpwatch stop pip_install_first
-
-echo
@@ -1,6 +1,8 @@
+#!/usr/bin/env bash
+
 set +e
 # Install dependencies with Pip.
-bpwatch start pip_uninstall
+
 if [[ -f .heroku/python/requirements-declared.txt ]]; then

  cp .heroku/python/requirements-declared.txt requirements-declared.txt
@@ -14,5 +16,5 @@ if [[ -f .heroku/python/requirements-declared.txt ]]; then
    /app/.heroku/python/bin/pip uninstall -r .heroku/python/requirements-stale.txt -y --exists-action=w | cleanup | indent
  fi
 fi
-bpwatch stop pip_uninstall
+
 set -e
@@ -1,10 +1,26 @@
+#!/usr/bin/env bash
+
 # Pipenv support (Generate requriements.txt with pipenv).
 if [[ -f Pipfile ]]; then
    if [[ ! -f requirements.txt ]]; then
-        puts-step "Generating 'requirements.txt' with pipenv"
+        puts-step "Installing requirements with latest Pipenv..."

+        # Install pipenv.
        /app/.heroku/python/bin/pip install pipenv --upgrade &> /dev/null

-        /app/.heroku/python/bin/pipenv lock --requirements --no-hashes > $BUILD_DIR/requirements.txt 2> /dev/null
+        if [[ ! -f Pipfile.lock ]]; then
+            /app/.heroku/python/bin/pipenv install --system --skip-lock 2>&1 | indent
+        else
+            /app/.heroku/python/bin/pipenv install --system 2>&1 | indent
+        fi
+        # Install the dependencies.
+
+
+        # Skip pip install, later.
+        export SKIP_PIP_INSTALL=1
+
+        # Pip freeze, for compatibility.
+        /app/.heroku/python/bin/pip freeze > requirements.txt
+
    fi
-fi
+fi
@@ -1,6 +1,8 @@
+#!/usr/bin/env bash
+
 # Detect Python-version with Pipenv.

-if [[ -f $BUILD_DIR/Pipfile.lock ]]; then
+if [[ -f $BUILD_DIR/Pipfile ]]; then

    if [[ ! -f $BUILD_DIR/runtime.txt ]]; then
        if [[ ! -f $BUILD_DIR/Pipfile.lock ]]; then
@@ -8,14 +10,14 @@ if [[ -f $BUILD_DIR/Pipfile.lock ]]; then
        fi
        if [[ -f $BUILD_DIR/Pipfile.lock ]]; then
            set +e
-            PYTHON=$(cat $BUILD_DIR/Pipfile.lock | jq '._meta.requires.python_version' -r)
+            PYTHON=$(jq -r '._meta.requires.python_version' "$BUILD_DIR/Pipfile.lock")
            set -e

            if [ "$PYTHON" = 2.7 ]; then
-                echo "python-2.7.13" > $BUILD_DIR/runtime.txt
+                echo "python-2.7.13" > "$BUILD_DIR/runtime.txt"
            fi
            if [ "$PYTHON" = 3.6 ]; then
-                echo "python-3.6.0" > $BUILD_DIR/runtime.txt
+                echo "python-3.6.2" > "$BUILD_DIR/runtime.txt"
            fi
        fi
    fi
@@ -9,14 +9,17 @@
 #
 # 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.
-source $BIN_DIR/utils
-
-
-bpwatch start pylibmc_install
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"

 # If pylibmc exists within requirements, use vendored libmemcached.
 if (pip-grep -s requirements.txt pylibmc &> /dev/null) then
@@ -25,10 +28,9 @@ if (pip-grep -s requirements.txt pylibmc &> /dev/null) then
    echo "-----> Noticed pylibmc. Bootstrapping libmemcached."
    mkdir -p .heroku/vendor
    # Download and extract libmemcached into target vendor directory.
-    curl $VENDORED_MEMCACHED -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_MEMCACHED" -s | tar zxv -C .heroku/vendor &> /dev/null
  fi

-  export LIBMEMCACHED=$(pwd)/vendor
+  LIBMEMCACHED=$(pwd)/vendor
+  export LIBMEMCACHED
 fi
-
-bpwatch stop pylibmc_install
@@ -1,59 +1,47 @@
+#!/usr/bin/env bash
+
 set +e
 runtime-fixer runtime.txt
 PYTHON_VERSION=$(cat runtime.txt)

-# Install Python.
+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
+fi
+
 if [ -f .heroku/python-version ]; then
-  if [ ! $(cat .heroku/python-version) = $PYTHON_VERSION ]; then
-    bpwatch start uninstall_python
+  if [ ! "$(cat .heroku/python-version)" = "$PYTHON_VERSION" ]; then
      puts-step "Found $(cat .heroku/python-version), removing"
      rm -fr .heroku/python
-    bpwatch stop uninstall_python
  else
    SKIP_INSTALL=1
  fi
 fi

-if [ ! $STACK = $CACHED_PYTHON_STACK ]; then
-  bpwatch start uninstall_python
-    rm -fr .heroku/python .heroku/python-stack .heroku/vendor
-    unset SKIP_INSTALL
-  bpwatch stop uninstall_python
-fi
-
-
 if [ ! "$SKIP_INSTALL" ]; then
-  bpwatch start install_python
    puts-step "Installing $PYTHON_VERSION"

    # Prepare destination directory.
    mkdir -p .heroku/python

-    curl https://lang-python.s3.amazonaws.com/$STACK/runtimes/$PYTHON_VERSION.tar.gz -s | tar zxv -C .heroku/python &> /dev/null
-    if [[ $? != 0 ]] ; then
+    mcount "version.python.$PYTHON_VERSION"
+
+    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
    fi

-  bpwatch stop install_python
-
  # Record for future reference.
-  echo $PYTHON_VERSION > .heroku/python-version
-  echo $STACK > .heroku/python-stack
+  echo "$PYTHON_VERSION" > .heroku/python-version
+  echo "$STACK" > .heroku/python-stack
  FRESH_PYTHON=true

  hash -r
 fi

 # If Pip isn't up to date:
-if [ "$FRESH_PYTHON" ] || [[ ! $(pip --version) == *$PIP_VERSION* ]]; then
-  WORKING_DIR=$(pwd)
-
-  bpwatch start prepare_environment
-
-  TMPTARDIR=$(mktemp -d)
-  trap "rm -rf $TMPTARDIR" RETURN
+if [ "$FRESH_PYTHON" ] || [[ ! $(pip --version) == *$PIP_UPDATE* ]]; then

  puts-step "Installing pip"

@@ -61,9 +49,8 @@ if [ "$FRESH_PYTHON" ] || [[ ! $(pip --version) == *$PIP_VERSION* ]]; then
  rm -fr /app/.heroku/python/lib/python2.7/site-packages/pip-*
  rm -fr /app/.heroku/python/lib/python2.7/site-packages/setuptools-*

-  /app/.heroku/python/bin/python $ROOT_DIR/vendor/get-pip.py &> /dev/null
+  /app/.heroku/python/bin/python "$ROOT_DIR/vendor/get-pip.py" &> /dev/null

-  bpwatch stop prepare_environment
 fi

 set -e
@@ -1,11 +0,0 @@
-#!/usr/bin/env bash
-
-# Syntax sugar.
-source $BIN_DIR/utils
-
-if (pip-grep -s requirements.txt setuptools distribute &> /dev/null) then
-
-  puts-warn 'The package setuptools/distribute is listed in requirements.txt.'
-  puts-warn 'Please remove to ensure expected behavior. '
-
-fi
@@ -1,10 +1,12 @@
 #!/usr/bin/env bash

 # Syntax sugar.
-BIN_DIR=$(cd $(dirname $0); pwd) # absolute path
-source $BIN_DIR/utils
+BIN_DIR=$(cd "$(dirname "$0")" || return; pwd) # absolute path

-DISABLE_COLLECTSTATIC=1 "$(dirname ${0:-})/compile" "$1" "$2" "$3"
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
+
+DISABLE_COLLECTSTATIC=1 "$(dirname "${0:-}")/compile" "$1" "$2" "$3"

 if [[ -f "$1/requirements-test.txt" ]]; then
    /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
@@ -1,6 +1,15 @@
+#!/usr/bin/env bash
 shopt -s extglob
+shopt -s nullglob

-if [ $(uname) == Darwin ]; then
+# The standard library.
+if [[ ! -f  /tmp/stdlib.sh ]]; then
+  curl --retry 3 -s https://lang-common.s3.amazonaws.com/buildpack-stdlib/v8/stdlib.sh > /tmp/stdlib.sh
+fi
+# shellcheck source=/dev/null
+source /tmp/stdlib.sh
+
+if [ "$(uname)" == Darwin ]; then
    sed() { command sed -l "$@"; }
 else
    sed() { command sed -u "$@"; }
@@ -11,46 +20,20 @@ indent() {
  sed "s/^/       /"
 }

+
 # Clean up pip output
 cleanup() {
  sed -e 's/\.\.\.\+/.../g' | sed -e '/already satisfied/Id' | sed -e '/No files were found to uninstall/Id' | sed -e '/Overwriting/Id' | sed -e '/python executable/Id' | sed -e '/no previously-included files/Id'
 }

-# Buildpack Indented line.
-puts-line() {
-  echo "       $@"
-}
-
 # Buildpack Steps.
 puts-step() {
-  echo "-----> $@"
+  echo "-----> $*"
 }

 # Buildpack Warnings.
 puts-warn() {
-  echo " !     $@"
-}
-
-# Buildpack Commands.
-puts-cmd() {
-  echo "     $ $@"
-}
-
-# Usage: $ set-env key value
-set-env() {
-  echo "export $1=$2" >> $PROFILE_PATH
-  echo "export $1=$2" >> $EXPORT_PATH
-}
-
-# Usage: $ set-default-env key value
-set-default-env() {
-  echo "export $1=\${$1:-$2}" >> $PROFILE_PATH
-  echo "export $1=\${$1:-$2}" >> $EXPORT_PATH
-}
-
-# Usage: $ un-set-env key
-un-set-env() {
-  echo "unset $1" >> $PROFILE_PATH
+  echo " !     $*"
 }

 # Does some serious copying.
@@ -69,42 +52,9 @@ deep-cp() {
  )
 }

-# Does some serious moving.
-deep-mv() {
-  deep-cp "$1" "$2"
-  deep-rm "$1"
-}
-
-# Does some serious deleting.
-deep-rm() {
-  # subshell to avoid surprising caller with shopts.
-  (
-    shopt -s dotglob
-    rm -rf "$1"/!(.curlrc|.netrc|tmp|.|..)
-  )
-}
-
-
-sub-env() {
-
-  WHITELIST=${2:-''}
-  BLACKLIST=${3:-'^(GIT_DIR|PYTHONHOME|LD_LIBRARY_PATH|LIBRARY_PATH|PATH)$'}
-
-  # Python-specific variables.
-  export PYHONHOME=$BUILD_DIR/.heroku/python
-  export PYTHONPATH=$BUILD_DIR/
-
-  (
-    if [ -d "$ENV_DIR" ]; then
-      for e in $(ls $ENV_DIR); do
-        echo "$e" | grep -E "$WHITELIST" | grep -qvE "$BLACKLIST" &&
-        export "$e=$(cat $ENV_DIR/$e)"
-        :
-      done
-    fi
-
-    $1
-
-  )
+
+# Measure the size of the Python installation.
+measure-size() {
+  echo "$(du -s .heroku/python 2>/dev/null || echo 0) | awk '{print $1}')"
 }

@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 shopt -s extglob

 old-platform() {
@@ -7,6 +8,7 @@ old-platform() {
    puts-warn "This caused the security warning you saw above during the 'pip install' step."
    puts-warn "We recommend '$RECOMMENDED_PYTHON_VERSION', which you can specify in a 'runtime.txt' file."
    puts-warn "  -- Much Love, Heroku."
+    mcount 'warnings.python.old'
  fi
 }

@@ -16,6 +18,7 @@ pylibmc-missing() {
    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
 }

@@ -27,6 +30,7 @@ scipy-included() {
    puts-warn "There is, however, a buildpack available that makes it possible to use it on Heroku."
    puts-warn "You can learn more here:  https://devcenter.heroku.com/articles/python-c-deps"
    puts-warn "Sorry for the inconvenience.   -- Much Love, Heroku."
+    mcount 'warnings.scipy'
  fi
 }

@@ -37,6 +41,18 @@ distribute-included() {
    puts-warn "This library is automatically installed by Heroku and shouldn't be in"
    puts-warn "Your requirements.txt file. This can cause unexpected behavior."
    puts-warn "  -- Much Love, Heroku."
+    mcount 'warnings.distribute'
+  fi
+}
+
+six-included() {
+  if grep -qi 'Running setup.py install for six' "$WARNINGS_LOG"; then
+    echo
+    puts-warn "Hello! Your requirements.txt file contains the six package."
+    puts-warn "This library is automatically installed by Heroku and shouldn't be in"
+    puts-warn "Your requirements.txt file. This can cause unexpected behavior."
+    puts-warn "  -- Much Love, Heroku."
+    mcount 'warnings.six'
  fi
 }

@@ -45,5 +61,6 @@ show-warnings() {
  pylibmc-missing
  scipy-included
  distribute-included
+  six-included
 }

@@ -1,5 +1,7 @@
 # Python Buildpack Binaries

+For Cedar-14 stack
+------------------

 To get started with it, create an app on Heroku inside a clone of this repository, and set your S3 config vars:

@@ -28,4 +30,12 @@ If this works, run `bob deploy` instead of `bob build` to have the result upload

 To speed things up drastically, it'll usually be a good idea to `heroku run bash --size PX` instead.

-Enjoy :)
+For Heroku-16 stack
+-------------------
+
+1. Ensure GNU Make and Docker are installed.
+2. From the root of the buildpack repository, run: `make buildenv-heroku-16`
+3. Follow the instructions displayed!
+
+
+Enjoy :)
@@ -10,14 +10,15 @@ hash -r

 echo "Building gdal..."

-SOURCE_TARBALL='http://download.osgeo.org/gdal/1.11.1/gdal-1.11.1.tar.gz'
+VERSION="2.2.1"
+SOURCE_TARBALL="http://download.osgeo.org/gdal/${VERSION}/gdal-${VERSION}.tar.gz"

 curl -L $SOURCE_TARBALL | tar zx

-cd gdal-1.11.1
+pushd "gdal-${VERSION}"
 ./configure --prefix=$OUT_PREFIX --enable-static=no  &&
 make
 make install

 # Cleanup
-cd ..
+popd
@@ -10,14 +10,16 @@ hash -r

 echo "Building geos..."

-SOURCE_TARBALL='http://download.osgeo.org/geos/geos-3.4.3.tar.bz2'
+VERSION=3.6.2
+
+SOURCE_TARBALL="http://download.osgeo.org/geos/geos-${VERSION}.tar.bz2"

 curl -L $SOURCE_TARBALL | tar xj

-cd geos-3.4.3
+pushd "geos-${VERSION}"
 ./configure --prefix=$OUT_PREFIX --enable-static=no &&
 make
 make install

 # Cleanup
-cd ..
+popd
@@ -10,14 +10,15 @@ hash -r

 echo "Building gdal..."

-SOURCE_TARBALL='http://download.osgeo.org/proj/proj-4.8.0.tar.gz'
+VERSION=4.9.3
+SOURCE_TARBALL="http://download.osgeo.org/proj/proj-${VERSION}.tar.gz"

 curl -L $SOURCE_TARBALL | tar zx

-cd proj-4.8.0
-./configure --prefix=$OUT_PREFIX --enable-static=no &&
+pushd "proj-${VERSION}"
+./configure --prefix=$OUT_PREFIX --enable-static=no
 make
 make install

 # Cleanup
-cd ..
+popd
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+# Build Deps: libraries/sqlite
+
+# NOTICE: This formula only works for the cedar-14 and heroku-16 stacks, not cedar.
+
+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
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+# Build Deps: libraries/sqlite
+
+# NOTICE: This formula only works for the cedar-14 stack, not cedar.
+
+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
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+# Build Deps: libraries/sqlite
+
+OUT_PREFIX=$1
+
+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
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+# Build Deps: libraries/sqlite
+
+OUT_PREFIX=$1
+
+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
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+# Build Deps: libraries/sqlite
+
+OUT_PREFIX=$1
+
+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 $OUT_PREFIX/bin/python
@@ -13,3 +13,7 @@ cd src
 ./configure --prefix=$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 '{}' +
@@ -0,0 +1,18 @@
+#!/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
+
@@ -0,0 +1,18 @@
+#!/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
+
@@ -0,0 +1,21 @@
+#!/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/3.6.2/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
@@ -1 +1 @@
-bob-builder==0.0.5
+bob-builder==0.0.13
@@ -0,0 +1 @@
+cffi
@@ -0,0 +1 @@
+django
@@ -1 +1,2 @@
-wordnet
+city_database
+stopwords
@@ -0,0 +1 @@
+python-2.7.13
@@ -0,0 +1 @@
+pylibmc
@@ -1 +0,0 @@
-python-3.6.0
@@ -1,6 +1,5 @@
 #!/usr/bin/env bash

-
 testPipenv() {
  compile "pipenv"
  assertCapturedSuccess
@@ -8,7 +7,7 @@ testPipenv() {

 testPipenvVersion() {
  compile "pipenv-version"
-  assertCaptured "3.6.0"
+  assertCaptured "3.6.2"
  assertCapturedSuccess
 }

@@ -17,13 +16,17 @@ testNoRequirements() {
  assertCapturedError
 }

-
-testNLTK() {
-  compile "nltk"
-  assertCaptured "wordnet"
+testGEOS() {
+  BUILD_WITH_GEO_LIBRARIES=1 compile "geos"
+  assertCaptured "geos"
  assertCapturedSuccess
 }

+testNLTK() {
+  compile "nltk"
+  assertCaptured "Downloading NLTK packages: city_database stopwords"
+  assertCapturedSuccess
+}

 testSetupPy() {
  compile "setup-py"
@@ -44,6 +47,18 @@ testPsycopg2() {
  assertCapturedSuccess
 }

+testCffi() {
+  compile "cffi"
+  assertCaptured "cffi"
+  assertCapturedSuccess
+}
+
+testPylibmc() {
+  compile "pylibmc"
+  assertCaptured "pylibmc"
+  assertCapturedSuccess
+}
+
 testPython2() {
  compile "python2"
  assertCaptured "python-2.7.13"
@@ -52,11 +67,30 @@ testPython2() {

 testPython3() {
  compile "python3"
-  assertCaptured "python-3.6.0"
+  assertCaptured "python-3.6.2"
  assertCapturedSuccess
 }

+testSmartRequirements() {
+  local cache_dir="$(mktmpdir)"
+  compile "requirements-standard" "$cache_dir"
+  assertFile "requests" ".heroku/python/requirements-declared.txt"
+  assertCapturedSuccess
+  compile "psycopg2" "$cache_dir"
+  assertCaptured "Uninstalling requests"
+  assertFile "psycopg2" ".heroku/python/requirements-declared.txt"
+  assertCapturedSuccess
+}

+testStackChange() {
+  local cache_dir="$(mktmpdir)"
+  mkdir -p "${cache_dir}/.heroku"
+  echo "different-stack" > "${cache_dir}/.heroku/python-stack"
+  compile "requirements-standard" "$cache_dir"
+  assertCaptured "clearing cache"
+  assertFile "$STACK" ".heroku/python-stack"
+  assertCapturedSuccess
+}


 pushd $(dirname 0) >/dev/null
@@ -93,8 +93,14 @@ assertNotCaptured()

 assertCapturedSuccess()
 {
-  assertEquals "Expected captured exit code to be 0; was <${RETURN}>" "0" "${RETURN}"
-  assertEquals "Expected STD_ERR to be empty; was <$(cat ${STD_ERR})>" "" "$(cat ${STD_ERR})"
+  assertEquals "Captured exit code -" "0" "${RETURN}"
+  assertEquals "STD_ERR -" "" "$(cat ${STD_ERR})"
+
+  if [ $RETURN -ne 0 -a -z "$(cat ${STD_ERR})" ]; then
+    # Failing exit code but stderr was empty. Display stdout to help debugging.
+    cat $STD_OUT
+    echo
+  fi
 }

 # assertCapturedError [[expectedErrorCode] expectedErrorMsg]
@@ -144,6 +150,11 @@ _assertContains()
    esac

    fail "${msg:-${default_msg}}"
+
+    if [ "${haystack_type}" == "file" ]; then
+      echo
+      cat "${haystack}"
+    fi
  fi
 }

@@ -0,0 +1,29 @@
+case $(ulimit -u) in
+
+# Automatic configuration for Gunicorn's Workers setting.
+
+# Standard-1X (+Free, +Hobby) Dyno
+256)
+  export DYNO_RAM=512
+  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-2}
+  ;;
+
+# Standard-2X Dyno
+512)
+  export DYNO_RAM=1024
+  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-4}
+  ;;
+
+# Performance-M Dyno
+16384)
+  export DYNO_RAM=2560
+  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-8}
+  ;;
+
+# Performance-L Dyno
+32768)
+  export DYNO_RAM=14336
+  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-11}
+  ;;
+
+esac
@@ -1,14 +0,0 @@
-#!/usr/bin/python
-
-
-import os
-import sys
-
-
-DEFAULT_PATH = '{0}.zip'.format(os.path.abspath(__file__))
-BPWATCH_DISTRO_PATH = os.environ.get('BPWATCH_DISTRO_PATH', DEFAULT_PATH)
-
-sys.path.insert(0, BPWATCH_DISTRO_PATH)
-
-import bp_cli
-bp_cli.main()
@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""Usage:
+  sp-grep [-s] <package>...
+
+Options:
+  -h --help     Show this screen.
+"""
+from docopt import docopt
+from pkg_resources import DistributionNotFound, get_distribution
+
+
+def has_any_distribution(names, silent=False):
+    for name in names:
+        try:
+            get_distribution(name)
+        except DistributionNotFound:
+            continue
+
+        if not silent:
+            print('Package {name} found!'.format(name=name))
+
+        exit(0)
+
+    if not silent:
+        print('Not found.')
+
+    exit(1)
+
+
+def main():
+    args = docopt(__doc__, version='sp-grep')
+    has_any_distribution(names=args['<package>'], silent=args['-s'])
+
+
+if __name__ == '__main__':
+    main()
@@ -1,38 +1,2 @@
-if [[ "${WEB_CONCURRENCY:-}" == 0* ]]; then
-  # another buildpack set a default value, with leading zero
-  unset WEB_CONCURRENCY
-fi
-
-case $(ulimit -u) in
-
-# Automatic configuration for Gunicorn's Workers setting.
-# Leading zero padding so a subsequent buildpack can figure out that we set a value, and not the user
-
-# Standard-1X (+Free, +Hobby) Dyno
-256)
-  export DYNO_RAM=512
-  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-02}
-  ;;
-
-# Standard-2X Dyno
-512)
-  export DYNO_RAM=1024
-  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-04}
-  ;;
-
-# Performance-M Dyno
-16384)
-  export DYNO_RAM=2560
-  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-08}
-  ;;
-
-# Performance-L Dyno
-32768)
-  export DYNO_RAM=6656
-  export WEB_CONCURRENCY=${WEB_CONCURRENCY:-011}
-  ;;
-
-esac
-
 # Automatic configuration for Gunicorn's ForwardedAllowIPS setting.
 export FORWARDED_ALLOW_IPS='*'