[2.7] bpo-31351: Set return code in ensurepip when pip fails (GH-3734)

Previously ensurepip would always report success, even if the
pip installation failed.

(cherry picked from commit 9adda0cdf89432386b7a04444a6199b580d287a1)

6 files changed, 46 insertions, 10 deletions

diff --git a/Doc/library/ensurepip.rst b/Doc/library/ensurepip.rst
index a6358e44b1..b6f7120947 100644
--- a/Doc/library/ensurepip.rst
+++ b/Doc/library/ensurepip.rst
@@ -76,6 +76,9 @@ options:
 * ``--no-default-pip``: if a non-default installation is request, the ``pip``
   script will *not* be installed.
 
+.. versionchanged:: 2.7.15
+   The exit status is non-zero if the command fails.
+
 
 Module API
 ----------
diff --git a/Lib/ensurepip/__init__.py b/Lib/ensurepip/__init__.py
index c2abed84ef..ea2a5e6348 100644
--- a/Lib/ensurepip/__init__.py
+++ b/Lib/ensurepip/__init__.py
@@ -29,7 +29,7 @@ def _run_pip(args, additional_paths=None):
 
     # Install the bundled software
     import pip
-    pip.main(args)
+    return pip.main(args)
 
 
 def version():
@@ -60,6 +60,21 @@ def bootstrap(root=None, upgrade=False, user=False,
 
     Note that calling this function will alter both sys.path and os.environ.
     """
+    # Discard the return value
+    _bootstrap(root=root, upgrade=upgrade, user=user,
+               altinstall=altinstall, default_pip=default_pip,
+               verbosity=verbosity)
+
+
+def _bootstrap(root=None, upgrade=False, user=False,
+               altinstall=False, default_pip=True,
+               verbosity=0):
+    """
+    Bootstrap pip into the current Python installation (or the given root
+    directory). Returns pip command status code.
+
+    Note that calling this function will alter both sys.path and os.environ.
+    """
     if altinstall and default_pip:
         raise ValueError("Cannot use altinstall and default_pip together")
 
@@ -105,11 +120,10 @@ def bootstrap(root=None, upgrade=False, user=False,
         if verbosity:
             args += ["-" + "v" * verbosity]
 
-        _run_pip(args + [p[0] for p in _PROJECTS], additional_paths)
+        return _run_pip(args + [p[0] for p in _PROJECTS], additional_paths)
     finally:
         shutil.rmtree(tmpdir, ignore_errors=True)
 
-
 def _uninstall_helper(verbosity=0):
     """Helper to support a clean default uninstall process on Windows
 
@@ -135,7 +149,7 @@ def _uninstall_helper(verbosity=0):
     if verbosity:
         args += ["-" + "v" * verbosity]
 
-    _run_pip(args + [p[0] for p in reversed(_PROJECTS)])
+    return _run_pip(args + [p[0] for p in reversed(_PROJECTS)])
 
 
 def _main(argv=None):
@@ -196,7 +210,7 @@ def _main(argv=None):
 
     args = parser.parse_args(argv)
 
-    bootstrap(
+    return _bootstrap(
         root=args.root,
         upgrade=args.upgrade,
         user=args.user,
diff --git a/Lib/ensurepip/__main__.py b/Lib/ensurepip/__main__.py
index 77527d7a35..03eef0dd94 100644
--- a/Lib/ensurepip/__main__.py
+++ b/Lib/ensurepip/__main__.py
@@ -1,4 +1,5 @@
 import ensurepip
+import sys
 
 if __name__ == "__main__":
-    ensurepip._main()
+    sys.exit(ensurepip._main())
diff --git a/Lib/ensurepip/_uninstall.py b/Lib/ensurepip/_uninstall.py
index 750365ec4d..b257904328 100644
--- a/Lib/ensurepip/_uninstall.py
+++ b/Lib/ensurepip/_uninstall.py
@@ -2,6 +2,7 @@
 
 import argparse
 import ensurepip
+import sys
 
 
 def _main(argv=None):
@@ -23,8 +24,8 @@ def _main(argv=None):
 
     args = parser.parse_args(argv)
 
-    ensurepip._uninstall_helper(verbosity=args.verbosity)
+    return ensurepip._uninstall_helper(verbosity=args.verbosity)
 
 
 if __name__ == "__main__":
-    _main()
+    sys.exit(_main())
diff --git a/Lib/test/test_ensurepip.py b/Lib/test/test_ensurepip.py
index 3316fcfaa1..cb9d10a104 100644
--- a/Lib/test/test_ensurepip.py
+++ b/Lib/test/test_ensurepip.py
@@ -21,6 +21,7 @@ class EnsurepipMixin:
     def setUp(self):
         run_pip_patch = mock.patch("ensurepip._run_pip")
         self.run_pip = run_pip_patch.start()
+        self.run_pip.return_value = 0
         self.addCleanup(run_pip_patch.stop)
 
         # Avoid side effects on the actual os module
@@ -258,7 +259,7 @@ class TestBootstrappingMainFunction(EnsurepipMixin, unittest.TestCase):
         self.assertFalse(self.run_pip.called)
 
     def test_basic_bootstrapping(self):
-        ensurepip._main([])
+        exit_code = ensurepip._main([])
 
         self.run_pip.assert_called_once_with(
             [
@@ -270,6 +271,13 @@ class TestBootstrappingMainFunction(EnsurepipMixin, unittest.TestCase):
 
         additional_paths = self.run_pip.call_args[0][1]
         self.assertEqual(len(additional_paths), 2)
+        self.assertEqual(exit_code, 0)
+
+    def test_bootstrapping_error_code(self):
+        self.run_pip.return_value = 2
+        exit_code = ensurepip._main([])
+        self.assertEqual(exit_code, 2)
+
 
 
 class TestUninstallationMainFunction(EnsurepipMixin, unittest.TestCase):
@@ -284,7 +292,7 @@ class TestUninstallationMainFunction(EnsurepipMixin, unittest.TestCase):
 
     def test_basic_uninstall(self):
         with fake_pip():
-            ensurepip._uninstall._main([])
+            exit_code = ensurepip._uninstall._main([])
 
         self.run_pip.assert_called_once_with(
             [
@@ -293,6 +301,13 @@ class TestUninstallationMainFunction(EnsurepipMixin, unittest.TestCase):
             ]
         )
 
+        self.assertEqual(exit_code, 0)
+
+    def test_uninstall_error_code(self):
+        with fake_pip():
+            self.run_pip.return_value = 2
+            exit_code = ensurepip._uninstall._main([])
+        self.assertEqual(exit_code, 2)
 
 if __name__ == "__main__":
     test.test_support.run_unittest(__name__)
diff --git a/Misc/NEWS.d/next/Library/2017-09-17-15-24-25.bpo-31351.yQdKv-.rst b/Misc/NEWS.d/next/Library/2017-09-17-15-24-25.bpo-31351.yQdKv-.rst
new file mode 100644
index 0000000000..20f2c1bdc1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-09-17-15-24-25.bpo-31351.yQdKv-.rst
@@ -0,0 +1,2 @@
+python -m ensurepip now exits with non-zero exit code if pip bootstrapping
+has failed.