PyUnstable_InterpreterState_SetEvalFrameFunc() can now fail

Author: vstinner

Doc/c-api/init.rst

@@ -1470,6 +1470,8 @@ All of the following functions must be called after :c:func:`Py_Initialize`.
 
    Set the frame evaluation function.
 
+   Return ``0`` on success, or set an exception and return ``-1`` on error.
+
    See the :pep:`523` "Adding a frame evaluation API to CPython".
 
    .. versionadded:: next

Include/cpython/pystate.h

@@ -306,7 +306,7 @@ typedef PyObject* (*PyUnstable_FrameEvalFunction)(PyThreadState *tstate, struct
 
 PyAPI_FUNC(PyUnstable_FrameEvalFunction) PyUnstable_InterpreterState_GetEvalFrameFunc(
     PyInterpreterState *interp);
-PyAPI_FUNC(void) PyUnstable_InterpreterState_SetEvalFrameFunc(
+PyAPI_FUNC(int) PyUnstable_InterpreterState_SetEvalFrameFunc(
     PyInterpreterState *interp,
     PyUnstable_FrameEvalFunction eval_frame);
 

Modules/_testcapimodule.c

@@ -2606,13 +2606,16 @@ test_interpreter_setevalframefunc(PyObject *self, PyObject *Py_UNUSED(args))
 {
     PyInterpreterState *interp = PyInterpreterState_Get();
     PyUnstable_FrameEvalFunction eval_func;
+    int res;
 
     eval_func = PyUnstable_InterpreterState_GetEvalFrameFunc(interp);
 
-    PyUnstable_InterpreterState_SetEvalFrameFunc(interp, noop_eval);
+    res = PyUnstable_InterpreterState_SetEvalFrameFunc(interp, noop_eval);
+    assert(res == 0);
     assert(PyUnstable_InterpreterState_GetEvalFrameFunc(interp) == noop_eval);
 
-    PyUnstable_InterpreterState_SetEvalFrameFunc(interp, eval_func);
+    res = PyUnstable_InterpreterState_SetEvalFrameFunc(interp, eval_func);
+    assert(res == 0);
 
     Py_RETURN_NONE;
 }

Modules/_testinternalcapi.c

@@ -656,9 +656,12 @@ decode_locale_ex(PyObject *self, PyObject *args)
 static PyObject *
 set_eval_frame_default(PyObject *self, PyObject *Py_UNUSED(args))
 {
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    PyUnstable_FrameEvalFunction eval_func = _PyEval_EvalFrameDefault;
+    if (PyUnstable_InterpreterState_SetEvalFrameFunc(interp, eval_func) < 0) {
+        return NULL;
+    }
     module_state *state = get_module_state(self);
-    PyUnstable_InterpreterState_SetEvalFrameFunc(_PyInterpreterState_GET(),
-                                                 _PyEval_EvalFrameDefault);
     Py_CLEAR(state->record_list);
     Py_RETURN_NONE;
 }
@@ -690,8 +693,10 @@ set_eval_frame_record(PyObject *self, PyObject *list)
         return NULL;
     }
     Py_XSETREF(state->record_list, Py_NewRef(list));
-    PyUnstable_InterpreterState_SetEvalFrameFunc(_PyInterpreterState_GET(),
-                                                 record_eval);
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    if (PyUnstable_InterpreterState_SetEvalFrameFunc(interp, record_eval) < 0) {
+        return NULL;
+    }
     Py_RETURN_NONE;
 }
 

Python/perf_trampoline.c

@@ -470,7 +470,9 @@ _PyPerfTrampoline_SetCallbacks(_PyPerf_Callbacks *callbacks)
     }
 #ifdef PY_HAVE_PERF_TRAMPOLINE
     if (trampoline_api.state) {
-        _PyPerfTrampoline_Fini();
+        if (_PyPerfTrampoline_Fini() < 0) {
+            return -1;
+        }
     }
     trampoline_api.init_state = callbacks->init_state;
     trampoline_api.write_state = callbacks->write_state;
@@ -486,12 +488,18 @@ _PyPerfTrampoline_Init(int activate)
 #ifdef PY_HAVE_PERF_TRAMPOLINE
     PyThreadState *tstate = _PyThreadState_GET();
     if (!activate) {
-        PyUnstable_InterpreterState_SetEvalFrameFunc(tstate->interp, prev_eval_frame);
+        if (PyUnstable_InterpreterState_SetEvalFrameFunc(tstate->interp,
+                                                         prev_eval_frame) < 0) {
+            return -1;
+        }
         perf_status = PERF_STATUS_NO_INIT;
     }
     else if (tstate->interp->eval_frame != py_trampoline_evaluator) {
         prev_eval_frame = PyUnstable_InterpreterState_GetEvalFrameFunc(tstate->interp);
-        PyUnstable_InterpreterState_SetEvalFrameFunc(tstate->interp, py_trampoline_evaluator);
+        if (PyUnstable_InterpreterState_SetEvalFrameFunc(tstate->interp,
+                                                         py_trampoline_evaluator) < 0) {
+            return -1;
+        }
         extra_code_index = _PyEval_RequestCodeExtraIndex(NULL);
         if (extra_code_index == -1) {
             return -1;
@@ -517,7 +525,9 @@ _PyPerfTrampoline_Fini(void)
     }
     PyThreadState *tstate = _PyThreadState_GET();
     if (tstate->interp->eval_frame == py_trampoline_evaluator) {
-        PyUnstable_InterpreterState_SetEvalFrameFunc(tstate->interp, NULL);
+        if (PyUnstable_InterpreterState_SetEvalFrameFunc(tstate->interp, NULL) < 0) {
+            return -1;
+        }
     }
     if (perf_status == PERF_STATUS_OK) {
         trampoline_api.free_state(trampoline_api.state);
@@ -553,7 +563,9 @@ _PyPerfTrampoline_AfterFork_Child(void)
         if (perf_trampoline_type != PERF_TRAMPOLINE_TYPE_MAP) {
             return PyStatus_Error("Failed to copy perf map file as perf trampoline type is not type map.");
         }
-        _PyPerfTrampoline_Fini();
+        if (_PyPerfTrampoline_Fini() < 0) {
+            return PyStatus_Error("_PyPerfTrampoline_Fini() failed");
+        }
         char filename[256];
         pid_t parent_pid = getppid();
         snprintf(filename, sizeof(filename), "/tmp/perf-%d.map", parent_pid);
@@ -563,7 +575,9 @@ _PyPerfTrampoline_AfterFork_Child(void)
     } else {
         // Restart trampoline in file in child.
         int was_active = _PyIsPerfTrampolineActive();
-        _PyPerfTrampoline_Fini();
+        if (_PyPerfTrampoline_Fini() < 0) {
+            return PyStatus_Error("_PyPerfTrampoline_Fini() failed");
+        }
         if (was_active) {
             _PyPerfTrampoline_Init(1);
         }

Python/pylifecycle.c

@@ -1940,7 +1940,10 @@ finalize_interp_clear(PyThreadState *tstate)
         _Py_HashRandomization_Fini();
         _PyArg_Fini();
         _Py_ClearFileSystemEncoding();
-        _PyPerfTrampoline_Fini();
+        if (_PyPerfTrampoline_Fini() < 0) {
+            PyErr_FormatUnraisable("Exception ignored on "
+                                   "_PyPerfTrampoline_Fini()");
+        }
         _PyPerfTrampoline_FreeArenas();
     }
 

Python/pystate.c

@@ -2906,15 +2906,15 @@ PyUnstable_InterpreterState_GetEvalFrameFunc(PyInterpreterState *interp)
 }
 
 
-void
+int
 PyUnstable_InterpreterState_SetEvalFrameFunc(PyInterpreterState *interp,
                                              PyUnstable_FrameEvalFunction eval_frame)
 {
     if (eval_frame == _PyEval_EvalFrameDefault) {
         eval_frame = NULL;
     }
     if (eval_frame == interp->eval_frame) {
-        return;
+        return 0;
     }
 #ifdef _Py_TIER2
     if (eval_frame != NULL) {
@@ -2925,6 +2925,7 @@ PyUnstable_InterpreterState_SetEvalFrameFunc(PyInterpreterState *interp,
     _PyEval_StopTheWorld(interp);
     interp->eval_frame = eval_frame;
     _PyEval_StartTheWorld(interp);
+    return 0;
 }