From 4a3a682b12f93a03888e8b59f439bc5fe30d6055 Mon Sep 17 00:00:00 2001
From: Krzysztof Konopko <kkonopko@users.noreply.github.com>
Date: Mon, 15 Jun 2020 19:28:46 +0200
Subject: [PATCH] bpo-40448: ensurepip: Do not use cache (GH-19812)

ensurepip optionally installs or upgrades 'pip' and 'setuptools' using
the version of those modules bundled with Python.  The internal PIP
installation routine by default temporarily uses its cache, if it
exists.  This is undesirable as Python builds and installations may be
independent of the user running the build, whilst PIP cache location
is dependent on the user's environment and outside of the build
environment.

At the same time, there's no value in using the cache while installing
bundled modules.

This change disables PIP caching when used in ensurepip.
---
 Lib/ensurepip/__init__.py                        |  2 +-
 Lib/test/test_ensurepip.py                       | 16 ++++++++--------
 Misc/ACKS                                        |  1 +
 .../2020-06-15-12-22-53.bpo-40448.1dk8Bu.rst     |  2 ++
 4 files changed, 12 insertions(+), 9 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2020-06-15-12-22-53.bpo-40448.1dk8Bu.rst

diff --git a/Lib/ensurepip/__init__.py b/Lib/ensurepip/__init__.py
index 545fce656fd..d62b1187f90 100644
--- a/Lib/ensurepip/__init__.py
+++ b/Lib/ensurepip/__init__.py
@@ -119,7 +119,7 @@ def _bootstrap(*, root=None, upgrade=False, user=False,
             additional_paths.append(os.path.join(tmpdir, wheel_name))
 
         # Construct the arguments to be passed to the pip command
-        args = ["install", "--no-index", "--find-links", tmpdir]
+        args = ["install", "--no-cache-dir", "--no-index", "--find-links", tmpdir]
         if root:
             args += ["--root", root]
         if upgrade:
diff --git a/Lib/test/test_ensurepip.py b/Lib/test/test_ensurepip.py
index 89966893092..4786d28f39a 100644
--- a/Lib/test/test_ensurepip.py
+++ b/Lib/test/test_ensurepip.py
@@ -40,7 +40,7 @@ class TestBootstrap(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "setuptools", "pip",
             ],
             unittest.mock.ANY,
@@ -54,7 +54,7 @@ class TestBootstrap(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "--root", "/foo/bar/",
                 "setuptools", "pip",
             ],
@@ -66,7 +66,7 @@ class TestBootstrap(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "--user", "setuptools", "pip",
             ],
             unittest.mock.ANY,
@@ -77,7 +77,7 @@ class TestBootstrap(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "--upgrade", "setuptools", "pip",
             ],
             unittest.mock.ANY,
@@ -88,7 +88,7 @@ class TestBootstrap(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "-v", "setuptools", "pip",
             ],
             unittest.mock.ANY,
@@ -99,7 +99,7 @@ class TestBootstrap(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "-vv", "setuptools", "pip",
             ],
             unittest.mock.ANY,
@@ -110,7 +110,7 @@ class TestBootstrap(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "-vvv", "setuptools", "pip",
             ],
             unittest.mock.ANY,
@@ -260,7 +260,7 @@ class TestBootstrappingMainFunction(EnsurepipMixin, unittest.TestCase):
 
         self.run_pip.assert_called_once_with(
             [
-                "install", "--no-index", "--find-links",
+                "install", "--no-cache-dir", "--no-index", "--find-links",
                 unittest.mock.ANY, "setuptools", "pip",
             ],
             unittest.mock.ANY,
diff --git a/Misc/ACKS b/Misc/ACKS
index a505a3d7840..0fc1954a222 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -910,6 +910,7 @@ Vajrasky Kok
 Guido Kollerie
 Jacek Kołodziej
 Jacek Konieczny
+Krzysztof Konopko
 Arkady Koplyarov
 Peter A. Koren
 Марк Коренберг
diff --git a/Misc/NEWS.d/next/Library/2020-06-15-12-22-53.bpo-40448.1dk8Bu.rst b/Misc/NEWS.d/next/Library/2020-06-15-12-22-53.bpo-40448.1dk8Bu.rst
new file mode 100644
index 00000000000..a755c5faa67
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-06-15-12-22-53.bpo-40448.1dk8Bu.rst
@@ -0,0 +1,2 @@
+:mod:`ensurepip` now disables the use of `pip` cache when installing the
+bundled versions of `pip` and `setuptools`.  Patch by Krzysztof Konopko.