diff --git a/Lib/ensurepip/__init__.py b/Lib/ensurepip/__init__.py index 4bd85990e8614a..0552cf55db15f7 100644 --- a/Lib/ensurepip/__init__.py +++ b/Lib/ensurepip/__init__.py @@ -130,6 +130,15 @@ def _bootstrap(*, root=None, upgrade=False, user=False, Note that calling this function will alter both sys.path and os.environ. """ + + try: + import zlib + except ImportError: + raise ModuleNotFoundError( + "ensurepip requires the standard library module 'zlib' " + "to install pip." + ) from None + if altinstall and default_pip: raise ValueError("Cannot use altinstall and default_pip together") diff --git a/Lib/test/test_ensurepip.py b/Lib/test/test_ensurepip.py index 6d3c91b0b6d9f9..f6743d57ca28dd 100644 --- a/Lib/test/test_ensurepip.py +++ b/Lib/test/test_ensurepip.py @@ -60,6 +60,11 @@ def setUp(self): self.run_pip.return_value = 0 self.addCleanup(run_pip_patch.stop) + # Allow testing on zlib-less platforms by avoiding the check for zlib in _bootstrap() + zlib_patch = unittest.mock.patch.dict('sys.modules', {'zlib': unittest.mock.MagicMock()}) + zlib_patch.start() + self.addCleanup(zlib_patch.stop) + # Avoid side effects on the actual os module real_devnull = os.devnull os_patch = unittest.mock.patch("ensurepip.os") @@ -185,6 +190,16 @@ def test_pip_config_file_disabled(self): ensurepip.bootstrap() self.assertEqual(self.os_environ["PIP_CONFIG_FILE"], os.devnull) + def test_missing_zlib(self): + with unittest.mock.patch.dict('sys.modules', {'zlib': None}): + with self.assertRaises(ModuleNotFoundError) as cm: + ensurepip.bootstrap() + + error_msg = str(cm.exception) + self.assertIn("ensurepip requires the standard library module 'zlib'", error_msg) + + self.assertFalse(self.run_pip.called) + @contextlib.contextmanager def fake_pip(version=ensurepip.version()): if version is None: diff --git a/Misc/NEWS.d/next/Library/2025-10-11-14-37-42.gh-issue-139823.uGF4oh.rst b/Misc/NEWS.d/next/Library/2025-10-11-14-37-42.gh-issue-139823.uGF4oh.rst new file mode 100644 index 00000000000000..43fe05d569964d --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-10-11-14-37-42.gh-issue-139823.uGF4oh.rst @@ -0,0 +1,2 @@ +:mod:`ensurepip` now fails with a nicer error message when the :mod:`zlib` +module is not available.