From 8eb2954e92942979e57c6ca80b093b7eb6b50b64 Mon Sep 17 00:00:00 2001
From: Claudio Jolowicz <claudio.jolowicz@cyren.com>
Date: Thu, 3 Oct 2019 16:47:29 +0200
Subject: [PATCH] Pin to pip 9.0.2 for pipenv users only

This addresses an issue raised by @CaseyFeist during code review:

  Updating pip for pipenv users or requiring them to update without a
  heads up won't be a good experience (our version is old enough that
  they'll need to uninstall and reinstall pipenv locally to successfully
  update). If you can refactor this to stay pinned to current version for
  pipenv users only, I should be able to accept this (and the related
  project updates).

  https://github.com/heroku/heroku-buildpack-python/pull/833#issuecomment-537758441
---
 bin/compile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/bin/compile b/bin/compile
index 5a0292e..db2d838 100755
--- a/bin/compile
+++ b/bin/compile
@@ -77,6 +77,11 @@ for file in "$BUILD_DIR/runtime.txt" "$CACHE_DIR/.heroku/python-version" ; do
     esac
 done
 
+if [[ -f "$BUILD_DIR/Pipfile" ]]; then
+    # Do not force pipenv users to re-install pipenv locally.
+    PIP_UPDATE="9.0.2"
+fi
+
 export DEFAULT_PYTHON_STACK PIP_UPDATE
 export PY37 PY36 PY35 PY27 PY34