Return an ExceptionSnapshot from _interpreters.exec().

python · ericsnowcurrently · Nov 6, 2023 · Sep 21, 2023 · Oct 5, 2023 · Oct 24, 2023
commit e73b9cc944e99802fada50752dc177e7cb4267e9
diff --git a/Lib/test/support/interpreters.py b/Lib/test/support/interpreters.py
@@ -116,7 +116,18 @@ def run(self, src_str, /, *, init=None):
         that time, the previous interpreter is allowed to run
         in other threads.
         """
-        _interpreters.exec(self._id, src_str, init)
+        err = _interpreters.exec(self._id, src_str, init)
+        if err is not None:
+            if err.name is not None:
+                if err.msg is not None:
+                    msg = f'{err.name}: {err.msg}'
+                else:
+                    msg = err.name
+            elif err.msg is not None:
+                msg = err.msg
+            else:
+                msg = None
+            raise RunFailedError(msg)
 
 
 def create_channel():

diff --git a/Lib/test/test__xxinterpchannels.py b/Lib/test/test__xxinterpchannels.py
@@ -1017,16 +1017,16 @@ def test_close_multiple_users(self):
             _channels.recv({cid})
             """))
         channels.close(cid)
-        with self.assertRaises(interpreters.RunFailedError) as cm:
-            interpreters.run_string(id1, dedent(f"""
+
+        excsnap = interpreters.run_string(id1, dedent(f"""
                 _channels.send({cid}, b'spam')
                 """))
-        self.assertIn('ChannelClosedError', str(cm.exception))
-        with self.assertRaises(interpreters.RunFailedError) as cm:
-            interpreters.run_string(id2, dedent(f"""
+        self.assertIn('ChannelClosedError', excsnap.type)
+
+        excsnap = interpreters.run_string(id2, dedent(f"""
                 _channels.send({cid}, b'spam')
                 """))
-        self.assertIn('ChannelClosedError', str(cm.exception))
+        self.assertIn('ChannelClosedError', excsnap.type)
 
     def test_close_multiple_times(self):
         cid = channels.create()

diff --git a/Lib/test/test__xxsubinterpreters.py b/Lib/test/test__xxsubinterpreters.py
@@ -743,30 +743,33 @@ def assert_run_failed(self, exctype, msg=None):
                              "{}: {}".format(exctype.__name__, msg))
 
     def test_invalid_syntax(self):
-        with self.assert_run_failed(SyntaxError):
-            # missing close paren
-            interpreters.run_string(self.id, 'print("spam"')
+        # missing close paren
+        exc = interpreters.run_string(self.id, 'print("spam"')
+        self.assertEqual(exc.type, 'SyntaxError')
 
     def test_failure(self):
-        with self.assert_run_failed(Exception, 'spam'):
-            interpreters.run_string(self.id, 'raise Exception("spam")')
+        exc = interpreters.run_string(self.id, 'raise Exception("spam")')
+        self.assertEqual(exc.type, 'Exception')
+        self.assertEqual(exc.msg, 'spam')
 
     def test_SystemExit(self):
-        with self.assert_run_failed(SystemExit, '42'):
-            interpreters.run_string(self.id, 'raise SystemExit(42)')
+        exc = interpreters.run_string(self.id, 'raise SystemExit(42)')
+        self.assertEqual(exc.type, 'SystemExit')
+        self.assertEqual(exc.msg, '42')
 
     def test_sys_exit(self):
-        with self.assert_run_failed(SystemExit):
-            interpreters.run_string(self.id, dedent("""
-                import sys
-                sys.exit()
-                """))
+        exc = interpreters.run_string(self.id, dedent("""
+            import sys
+            sys.exit()
+            """))
+        self.assertEqual(exc.type, 'SystemExit')
 
-        with self.assert_run_failed(SystemExit, '42'):
-            interpreters.run_string(self.id, dedent("""
-                import sys
-                sys.exit(42)
-                """))
+        exc = interpreters.run_string(self.id, dedent("""
+            import sys
+            sys.exit(42)
+            """))
+        self.assertEqual(exc.type, 'SystemExit')
+        self.assertEqual(exc.msg, '42')
 
     def test_with_shared(self):
         r, w = os.pipe()

@@ -1968,10 +1968,12 @@ def test_disallowed_reimport(self):
             print(_testsinglephase)
             ''')
         interpid = _interpreters.create()
-        with self.assertRaises(_interpreters.RunFailedError):
-            _interpreters.run_string(interpid, script)
-        with self.assertRaises(_interpreters.RunFailedError):
-            _interpreters.run_string(interpid, script)
+
+        excsnap = _interpreters.run_string(interpid, script)
+        self.assertIsNot(excsnap, None)
+
+        excsnap = _interpreters.run_string(interpid, script)
+        self.assertIsNot(excsnap, None)
 
 
 class TestSinglePhaseSnapshot(ModuleSnapshot):

@@ -655,25 +655,19 @@ def test_magic_number(self):
 @unittest.skipIf(_interpreters is None, 'subinterpreters required')
 class IncompatibleExtensionModuleRestrictionsTests(unittest.TestCase):
 
-    ERROR = re.compile("^ImportError: module (.*) does not support loading in subinterpreters")
-
     def run_with_own_gil(self, script):
         interpid = _interpreters.create(isolated=True)
-        try:
-            _interpreters.run_string(interpid, script)
-        except _interpreters.RunFailedError as exc:
-            if m := self.ERROR.match(str(exc)):
-                modname, = m.groups()
-                raise ImportError(modname)
+        excsnap = _interpreters.run_string(interpid, script)
+        if excsnap is not None:
+            if excsnap.type == 'ImportError':
+                raise ImportError(excsnap.msg)
 
     def run_with_shared_gil(self, script):
         interpid = _interpreters.create(isolated=False)
-        try:
-            _interpreters.run_string(interpid, script)
-        except _interpreters.RunFailedError as exc:
-            if m := self.ERROR.match(str(exc)):
-                modname, = m.groups()
-                raise ImportError(modname)
+        excsnap = _interpreters.run_string(interpid, script)
+        if excsnap is not None:
+            if excsnap.type == 'ImportError':
+                raise ImportError(excsnap.msg)
 
     @unittest.skipIf(_testsinglephase is None, "test requires _testsinglephase module")
     def test_single_phase_init_module(self):

diff --git a/Modules/_xxsubinterpretersmodule.c b/Modules/_xxsubinterpretersmodule.c
@@ -237,18 +237,17 @@ _run_script(PyObject *ns, const char *codestr, Py_ssize_t codestrlen, int flags)
 static int
 _run_in_interpreter(PyInterpreterState *interp,
                     const char *codestr, Py_ssize_t codestrlen,
-                    PyObject *shareables, int flags,
-                    PyObject *excwrapper)
+                    PyObject *shareables, int flags, PyObject **excsnap)
 {
     assert(!PyErr_Occurred());
     _PyXI_session session = {0};
 
     // Prep and switch interpreters.
     if (_PyXI_Enter(&session, interp, shareables) < 0) {
         assert(!PyErr_Occurred());
-        _PyXI_ApplyExceptionInfo(session.exc, excwrapper);
-        assert(PyErr_Occurred());
-        return -1;
+        *excsnap = _PyXI_ResolveCapturedException(&session, NULL);
+        assert((PyErr_Occurred() == NULL) != (*excsnap == NULL));
+        return PyErr_Occurred() ? -1 : 0;
     }
 
     // Run the script.
@@ -258,9 +257,12 @@ _run_in_interpreter(PyInterpreterState *interp,
     _PyXI_Exit(&session);
 
     // Propagate any exception out to the caller.
-    assert(!PyErr_Occurred());
     if (res < 0) {
-        _PyXI_ApplyCapturedException(&session, excwrapper);
+        *excsnap = _PyXI_ResolveCapturedException(&session, NULL);
+        assert((PyErr_Occurred() == NULL) != (*excsnap == NULL));
+        if (!PyErr_Occurred()) {
+            res = 0;
+        }
     }
     else {
         assert(!_PyXI_HasCapturedException(&session));
@@ -528,14 +530,15 @@ convert_code_arg(PyObject *arg, const char *fname, const char *displayname,
     return code;
 }
 
-static int
+static PyObject *
 _interp_exec(PyObject *self,
              PyObject *id_arg, PyObject *code_arg, PyObject *shared_arg)
 {
     // Look up the interpreter.
     PyInterpreterState *interp = PyInterpreterID_LookUp(id_arg);
     if (interp == NULL) {
-        return -1;
+        assert(PyErr_Occurred());
+        return NULL;
     }
 
     // Extract code.
@@ -545,20 +548,24 @@ _interp_exec(PyObject *self,
     const char *codestr = get_code_str(code_arg,
                                        &codestrlen, &bytes_obj, &flags);
     if (codestr == NULL) {
-        return -1;
+        assert(PyErr_Occurred());
+        return NULL;
     }
 
     // Run the code in the interpreter.
-    module_state *state = get_module_state(self);
-    assert(state != NULL);
+    PyObject *excsnap = NULL;
     int res = _run_in_interpreter(interp, codestr, codestrlen,
-                                  shared_arg, flags, state->RunFailedError);
+                                  shared_arg, flags, &excsnap);
     Py_XDECREF(bytes_obj);
     if (res < 0) {
-        return -1;
+        assert(PyErr_Occurred());
+        assert(excsnap == NULL);
+        return NULL;
     }
-
-    return 0;
+    else if (excsnap != NULL) {
+        return excsnap;
+    }
+    Py_RETURN_NONE;
 }
 
 static PyObject *
@@ -586,12 +593,9 @@ interp_exec(PyObject *self, PyObject *args, PyObject *kwds)
         return NULL;
     }
 
-    int res = _interp_exec(self, id, code, shared);
+    PyObject *res = _interp_exec(self, id, code, shared);
     Py_DECREF(code);
-    if (res < 0) {
-        return NULL;
-    }
-    Py_RETURN_NONE;
+    return res;
 }
 
 PyDoc_STRVAR(exec_doc,
@@ -629,12 +633,9 @@ interp_run_string(PyObject *self, PyObject *args, PyObject *kwds)
         return NULL;
     }
 
-    int res = _interp_exec(self, id, script, shared);
+    PyObject *res = _interp_exec(self, id, script, shared);
     Py_DECREF(script);
-    if (res < 0) {
-        return NULL;
-    }
-    Py_RETURN_NONE;
+    return res;
 }
 
 PyDoc_STRVAR(run_string_doc,
@@ -663,12 +664,9 @@ interp_run_func(PyObject *self, PyObject *args, PyObject *kwds)
         return NULL;
     }
 
-    int res = _interp_exec(self, id, (PyObject *)code, shared);
+    PyObject *res = _interp_exec(self, id, (PyObject *)code, shared);
     Py_DECREF(code);
-    if (res < 0) {
-        return NULL;
-    }
-    Py_RETURN_NONE;
+    return res;
 }
 
 PyDoc_STRVAR(run_func_doc,