Add tests for venv and getpath in the case where Python is symlinked

Author: pelson

Lib/test/test_getpath.py

@@ -864,6 +864,56 @@ def test_PYTHONHOME_in_venv(self):
         actual = getpath(ns, expected)
         self.assertEqual(expected, actual)
 
+    def test_venv_w_symlinked_base_executable(self):
+        """
+        If we symlink the base executable, and point to it via home in pyvenv.cfg,
+        we should have it as sys.executable (and sys.prefix should be the resolved location)
+        """
+        ns = MockPosixNamespace(
+            argv0="/venv/bin/python3",
+            PREFIX="/some/_internal/prefix",
+            base_exec_prefix="/foo/bar"
+        )
+        # Setup venv
+        ns.add_known_xfile("/venv/bin/python3")
+        ns.add_known_xfile("/usr/local/bin/python3")
+        ns.add_known_xfile("/some/_internal/prefix/bin/python3")
+
+        ns.add_known_file("/venv/pyvenv.cfg", [
+            # The published based executable location is /usr/local/bin - we don't want to
+            # expose /some/internal/directory (this location can change under our feet)
+            r"home = /usr/local/bin"
+        ])
+        ns.add_known_link("/venv/bin/python3", "/usr/local/bin/python3")
+        ns.add_known_link("/usr/local/bin/python3", "/some/_internal/prefix/bin/python3")
+
+        ns.add_known_file("/some/_internal/prefix/lib/python9.8/os.py")
+        ns.add_known_dir("/some/_internal/prefix/lib/python9.8/lib-dynload")
+
+        # Put a file completely outside of /usr/local to validate that the issue
+        # in https://github.com/python/cpython/issues/106045 is resolved.
+        ns.add_known_dir("/usr/lib/python9.8/lib-dynload")
+
+        expected = dict(
+            executable="/venv/bin/python3",
+            prefix="/venv",
+            exec_prefix="/venv",
+            base_prefix="/some/_internal/prefix",
+            base_exec_prefix="/some/_internal/prefix",
+            # It is important to maintain the link to the original executable, as this
+            # is used when creating a new virtual environment (which should also have home
+            # set to /usr/local/bin to avoid bleeding the internal path to the venv)
+            base_executable="/usr/local/bin/python3",
+            module_search_paths_set=1,
+            module_search_paths=[
+                "/some/_internal/prefix/lib/python98.zip",
+                "/some/_internal/prefix/lib/python9.8",
+                "/some/_internal/prefix/lib/python9.8/lib-dynload",
+            ],
+        )
+        actual = getpath(ns, expected)
+        self.assertEqual(expected, actual)
+
 # ******************************************************************************
 
 DEFAULT_NAMESPACE = dict(

Lib/test/test_venv.py

@@ -752,6 +752,50 @@ def test_zippath_from_non_installed_posix(self):
         out, err = check_output(cmd)
         self.assertTrue(zip_landmark.encode() in out)
 
+    @unittest.skipIf(os.name == 'nt', 'not relevant on Windows')
+    @requireVenvCreate
+    def test_venv_from_venv_with_symlink(self):
+        """
+        Test that we can create a venv from a venv using a base Python that is
+        a symlink, without exposing the location of the symlink in pyvenv.cfg.
+        """
+        rmtree(self.env_dir)
+        public_prefix = os.path.realpath(tempfile.mkdtemp())
+        self.addCleanup(rmtree, public_prefix)
+        public_bin_dir = os.path.join(public_prefix, 'bin')
+        os.mkdir(public_bin_dir)
+        public_exe = os.path.join(public_bin_dir, self.exe)
+        os.symlink(sys.executable, public_exe)
+        cmd = [public_exe,
+               "-m",
+               "venv",
+               "--without-pip",
+               "--without-scm-ignore-files",
+               self.env_dir]
+
+        subprocess.check_call(cmd)
+
+        # Verify that we don't expose the internal prefix to the first venv config:
+        contents = (pathlib.Path(self.env_dir) / 'pyvenv.cfg').read_text()
+        self.assertIn(f'home = {public_bin_dir}\n', contents)
+
+        # Now use the venv to make another, and assert that the internal env is
+        # also not exposed there.
+        second_venv = os.path.realpath(tempfile.mkdtemp())
+        self.addCleanup(rmtree, second_venv)
+
+        cmd = [os.path.join(self.env_dir, 'bin', 'python3'),
+               "-m",
+               "venv",
+               "--without-pip",
+               "--without-scm-ignore-files",
+               second_venv]
+
+        subprocess.check_call(cmd)
+
+        contents = (pathlib.Path(second_venv) / 'pyvenv.cfg').read_text()
+        self.assertIn(f'home = {public_bin_dir}\n', contents)
+
     @requireVenvCreate
     def test_activate_shell_script_has_no_dos_newlines(self):
         """