bpo-43541: Fix PyEval_EvalCodeEx() regression (GH-24918)

vstinner · web-flow · commit fc980e0be197 · 2021-03-18T14:51:24.000+01:00
* Remove an assertion which required CO_NEWLOCALS and CO_OPTIMIZED code flags. It is ok to call this function on a code with these flags set. * Fix reference counting on builtins: remove Py_DECREF(). Fix regression introduced in the commit 46496f9. Add also a comment to document that _PyEval_BuiltinsFromGlobals() returns a borrowed reference.
diff --git a/Misc/NEWS.d/next/C API/2021-03-18-12-44-33.bpo-43541.ICigzd.rst b/Misc/NEWS.d/next/C API/2021-03-18-12-44-33.bpo-43541.ICigzd.rst
@@ -0,0 +1,2 @@
+Fix a ``PyEval_EvalCodeEx()`` regression: fix reference counting on
+builtins. Patch by Victor Stinner.
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
@@ -847,7 +847,7 @@ PyFrameObject*
 PyFrame_New(PyThreadState *tstate, PyCodeObject *code,
             PyObject *globals, PyObject *locals)
 {
-    PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);
+    PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref
     if (builtins == NULL) {
         return NULL;
     }
diff --git a/Objects/funcobject.c b/Objects/funcobject.c
@@ -50,7 +50,7 @@ PyFunction_NewWithQualName(PyObject *code, PyObject *globals, PyObject *qualname
     }
     Py_XINCREF(module);
 
-    builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);
+    builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref
     if (builtins == NULL) {
         goto error;
     }
diff --git a/Python/ceval.c b/Python/ceval.c
@@ -1127,7 +1127,7 @@ PyEval_EvalCode(PyObject *co, PyObject *globals, PyObject *locals)
     if (locals == NULL) {
         locals = globals;
     }
-    PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);
+    PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref
     if (builtins == NULL) {
         return NULL;
     }
@@ -5140,12 +5140,11 @@ PyEval_EvalCodeEx(PyObject *_co, PyObject *globals, PyObject *locals,
     if (defaults == NULL) {
         return NULL;
     }
-    PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);
+    PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref
     if (builtins == NULL) {
         Py_DECREF(defaults);
         return NULL;
     }
-    assert ((((PyCodeObject *)_co)->co_flags & (CO_NEWLOCALS | CO_OPTIMIZED)) == 0);
     if (locals == NULL) {
         locals = globals;
     }
@@ -5208,7 +5207,6 @@ PyEval_EvalCodeEx(PyObject *_co, PyObject *globals, PyObject *locals,
     }
 fail:
     Py_DECREF(defaults);
-    Py_DECREF(builtins);
     return res;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Fix a ``PyEval_EvalCodeEx()`` regression: fix reference counting on
	`2`	`+builtins. Patch by Victor Stinner.`
Original file line number	Diff line number	Diff line change
`@@ -847,7 +847,7 @@ PyFrameObject*`
`847`	`847`	`PyFrame_New(PyThreadState tstate, PyCodeObject code,`
`848`	`848`	`PyObject globals, PyObject locals)`
`849`	`849`	`{`
`850`		`- PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);`
	`850`	`+ PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref`
`851`	`851`	`if (builtins == NULL) {`
`852`	`852`	`return NULL;`
`853`	`853`	`}`
Original file line number	Diff line number	Diff line change
`@@ -50,7 +50,7 @@ PyFunction_NewWithQualName(PyObject code, PyObject globals, PyObject *qualname`
`50`	`50`	`}`
`51`	`51`	`Py_XINCREF(module);`
`52`	`52`
`53`		`- builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);`
	`53`	`+ builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref`
`54`	`54`	`if (builtins == NULL) {`
`55`	`55`	`goto error;`
`56`	`56`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1127,7 +1127,7 @@ PyEval_EvalCode(PyObject co, PyObject globals, PyObject *locals)`
`1127`	`1127`	`if (locals == NULL) {`
`1128`	`1128`	`locals = globals;`
`1129`	`1129`	`}`
`1130`		`- PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);`
	`1130`	`+ PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref`
`1131`	`1131`	`if (builtins == NULL) {`
`1132`	`1132`	`return NULL;`
`1133`	`1133`	`}`
`@@ -5140,12 +5140,11 @@ PyEval_EvalCodeEx(PyObject _co, PyObject globals, PyObject *locals,`
`5140`	`5140`	`if (defaults == NULL) {`
`5141`	`5141`	`return NULL;`
`5142`	`5142`	`}`
`5143`		`- PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals);`
	`5143`	`+ PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref`
`5144`	`5144`	`if (builtins == NULL) {`
`5145`	`5145`	`Py_DECREF(defaults);`
`5146`	`5146`	`return NULL;`
`5147`	`5147`	`}`
`5148`		`- assert ((((PyCodeObject *)_co)->co_flags & (CO_NEWLOCALS \| CO_OPTIMIZED)) == 0);`
`5149`	`5148`	`if (locals == NULL) {`
`5150`	`5149`	`locals = globals;`
`5151`	`5150`	`}`
`@@ -5208,7 +5207,6 @@ PyEval_EvalCodeEx(PyObject _co, PyObject globals, PyObject *locals,`
`5208`	`5207`	`}`
`5209`	`5208`	`fail:`
`5210`	`5209`	`Py_DECREF(defaults);`
`5211`		`- Py_DECREF(builtins);`
`5212`	`5210`	`return res;`
`5213`	`5211`	`}`
`5214`	`5212`