From 46581612fc40e5f0fcb87a21ed31adc973b4a4b1 Mon Sep 17 00:00:00 2001
From: Ed Morley <501702+edmorley@users.noreply.github.com>
Date: Tue, 28 Jul 2020 23:34:18 +0100
Subject: [PATCH] Install pip and setuptools in the same pip invocation (#1007)

`get-pip.py` installs setuptools itself (if it's not already installed):
https://pip.pypa.io/en/stable/installing/#installing-with-get-pip-py
https://github.com/pypa/get-pip/blob/eff16c878c7fd6b688b9b4c4267695cf1a0bf01b/templates/default.py#L152-L153

This means that previously the latest version of setuptools (currently
`49.2.0`) was being installed from PyPI, and then immediately after the
target version (currently `39.0.1`) installed over it.

This added time to the build unnecessarily.

The version of setuptools installed by `get-pip.py` can be overridden
by passing in a version as a normal requirements specifier.

Fixes #1001.
---
 bin/steps/python | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/bin/steps/python b/bin/steps/python
index 381cc2188..d297b374e 100755
--- a/bin/steps/python
+++ b/bin/steps/python
@@ -169,8 +169,7 @@ if [ "$FRESH_PYTHON" ] || [[ ! $(pip --version) == *${PIP_VERSION}* ]]; then
   rm -fr /app/.heroku/python/lib/python*/site-packages/pip-*
   rm -fr /app/.heroku/python/lib/python*/site-packages/setuptools-*
 
-  /app/.heroku/python/bin/python "$GETPIP_PY" pip=="${PIP_VERSION}" &> /dev/null
-  /app/.heroku/python/bin/pip install "setuptools==${SETUPTOOLS_VERSION}" &> /dev/null
+  /app/.heroku/python/bin/python "$GETPIP_PY" pip=="${PIP_VERSION}" "setuptools==${SETUPTOOLS_VERSION}" &> /dev/null
 fi
 
 set -e