[3.11] GH-91742: Fix pdb crash after jump (GH-94171) (#94176)

miss-islington · kumaraditya303 · web-flow · commit 1f00e8c55ec4 · 2022-06-23T17:36:00.000+01:00
Co-authored-by: Kumar Aditya &lt;59607654+kumaraditya303@users.noreply.github.com&gt;
diff --git a/Lib/test/test_pdb.py b/Lib/test/test_pdb.py
@@ -1363,7 +1363,50 @@ def test_pdb_issue_43318():
     4
     """
 
+def test_pdb_issue_gh_91742():
+    """See GH-91742
 
+    >>> def test_function():
+    ...    __author__ = "pi"
+    ...    __version__ = "3.14"
+    ...
+    ...    def about():
+    ...        '''About'''
+    ...        print(f"Author: {__author__!r}",
+    ...            f"Version: {__version__!r}",
+    ...            sep=" ")
+    ...
+    ...    import pdb; pdb.Pdb(nosigint=True, readrc=False).set_trace()
+    ...    about()
+
+
+    >>> reset_Breakpoint()
+    >>> with PdbTestInput([  # doctest: +NORMALIZE_WHITESPACE
+    ...     'step',
+    ...     'next',
+    ...     'next',
+    ...     'jump 5',
+    ...     'continue'
+    ... ]):
+    ...     test_function()
+    > <doctest test.test_pdb.test_pdb_issue_gh_91742[0]>(12)test_function()
+    -> about()
+    (Pdb) step
+    --Call--
+    > <doctest test.test_pdb.test_pdb_issue_gh_91742[0]>(5)about()
+    -> def about():
+    (Pdb) next
+    > <doctest test.test_pdb.test_pdb_issue_gh_91742[0]>(7)about()
+    -> print(f"Author: {__author__!r}",
+    (Pdb) next
+    > <doctest test.test_pdb.test_pdb_issue_gh_91742[0]>(8)about()
+    -> f"Version: {__version__!r}",
+    (Pdb) jump 5
+    > <doctest test.test_pdb.test_pdb_issue_gh_91742[0]>(5)about()
+    -> def about():
+    (Pdb) continue
+    Author: 'pi' Version: '3.14'
+    """
 @support.requires_subprocess()
 class PdbTestCase(unittest.TestCase):
     def tearDown(self):
diff --git a/Misc/NEWS.d/next/Library/2022-06-23-13-12-05.gh-issue-91742.sNytVX.rst b/Misc/NEWS.d/next/Library/2022-06-23-13-12-05.gh-issue-91742.sNytVX.rst
@@ -0,0 +1 @@
+Fix :mod:`pdb` crash after jump caused by a null pointer dereference. Patch by Kumar Aditya.
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
@@ -418,7 +418,7 @@ static void
 frame_stack_pop(PyFrameObject *f)
 {
     PyObject *v = _PyFrame_StackPop(f->f_frame);
-    Py_DECREF(v);
+    Py_XDECREF(v);
 }
 
 static PyFrameState

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Fix :mod:`pdb` crash after jump caused by a null pointer dereference. Patch by Kumar Aditya.
Original file line number	Diff line number	Diff line change
`@@ -418,7 +418,7 @@ static void`
`418`	`418`	`frame_stack_pop(PyFrameObject *f)`
`419`	`419`	`{`
`420`	`420`	`PyObject *v = _PyFrame_StackPop(f->f_frame);`
`421`		`- Py_DECREF(v);`
	`421`	`+ Py_XDECREF(v);`
`422`	`422`	`}`
`423`	`423`
`424`	`424`	`static PyFrameState`