[3.11] gh-87115: Set __main__.__spec__ to None in pdb (GH-116141) (#116155)

* gh-87115: Set `__main__.__spec__` to `None` in pdb (#116141)

(cherry picked from commit ccfc042)

* [3.11] gh-87115: Set `__main__.__spec__` to `None` in pdb (GH-116141)
(cherry picked from commit ccfc042)

Co-authored-by: Tian Gao <[email protected]>

Author: gaogaotiantian

Lib/pdb.py

@@ -153,6 +153,7 @@ def namespace(self):
             __name__='__main__',
             __file__=self,
             __builtins__=__builtins__,
+            __spec__=None,
         )
 
     @property

Lib/test/test_pdb.py

@@ -1862,6 +1862,18 @@ def bœr():
             ('bœr', 1),
         )
 
+    def test_spec(self):
+        # Test that __main__.__spec__ is set to None when running a script
+        script = """
+            import __main__
+            print(__main__.__spec__)
+        """
+
+        commands = "continue"
+
+        stdout, _ = self.run_pdb_script(script, commands)
+        self.assertIn('None', stdout)
+
     def test_issue7964(self):
         # open the file as binary so we can force \r\n newline
         with open(os_helper.TESTFN, 'wb') as f:

Misc/NEWS.d/next/Library/2024-02-29-20-06-06.gh-issue-87115.FVMiOR.rst

@@ -0,0 +1 @@
+Set ``__main__.__spec__`` to ``None`` when running a script with :mod:`pdb`