gh-143768: Replace a dangling interpreter symlink when creating a venv

Author: claydugo

Lib/test/test_venv.py

@@ -608,6 +608,33 @@ def test_failed_symlink(self):
             filepath_regex = r"'[A-Z]:\\\\(?:[^\\\\]+\\\\)*[^\\\\]+'"
             self.assertRegex(err, rf"Unable to symlink {filepath_regex} to {filepath_regex}")
 
+    @requireVenvCreate
+    @unittest.skipIf(os.name == 'nt', 'not relevant on Windows')
+    @unittest.skipUnless(can_symlink(), 'Needs symlinks')
+    def test_broken_symlink_in_existing_venv(self):
+        """
+        Test creating a venv when a stale venv with broken symlinks exists.
+        """
+        bindir = os.path.join(self.env_dir, self.bindir)
+        os.makedirs(bindir)
+        python = os.path.join(bindir, 'python3')
+        os.symlink('/path/to/deleted/conda/env/bin/python3', python)
+        self.assertTrue(os.path.islink(python))
+        self.assertFalse(os.path.exists(python))
+
+        builder = venv.EnvBuilder(with_pip=False, symlinks=True)
+        self.run_with_capture(builder.create, self.env_dir)
+        self.assertTrue(os.path.islink(python))
+        self.assertTrue(os.path.exists(python))
+
+        rmtree(self.env_dir)
+        os.makedirs(bindir)
+        os.symlink('/path/to/deleted/conda/env/bin/python3', python)
+        builder = venv.EnvBuilder(with_pip=False, symlinks=False)
+        self.run_with_capture(builder.create, self.env_dir)
+        self.assertFalse(os.path.islink(python))
+        self.assertTrue(os.path.exists(python))
+
     @requireVenvCreate
     def test_multiprocessing(self):
         """

Lib/venv/__init__.py

@@ -267,6 +267,8 @@ def symlink_or_copy(self, src, dst, relative_symlinks_ok=False):
         switch to a different set of files instead.)
         """
         assert os.name != 'nt'
+        if os.path.islink(dst) and not os.path.exists(dst):
+            os.unlink(dst)
         force_copy = not self.symlinks
         if not force_copy:
             try:

Misc/NEWS.d/next/Library/2026-06-05-16-57-03.gh-issue-143768.RbLnkFx.rst

@@ -0,0 +1,3 @@
+:mod:`venv`: Replace a dangling interpreter symlink in an existing
+environment instead of failing or silently leaving it broken. Fix by
+Clay Dugo.