Show chained exception frames in stack. Fixes #1042

src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py

@@ -1420,7 +1420,6 @@ def build_exception_info_response(dbg, thread_id, request_seq, set_additional_th
         try:
             try:
                 frames_list = dbg.suspended_frames_manager.get_frames_list(thread_id)
-                memo = set()
                 while frames_list is not None and len(frames_list):
                     frames = []
 
@@ -1483,8 +1482,7 @@ def build_exception_info_response(dbg, thread_id, request_seq, set_additional_th
                     stack_str += frames_list.exc_context_msg
                     stack_str_lst.append(stack_str)
 
-                    frames_list = create_frames_list_from_exception_cause(
+                    frames_list = frames_list.chained_frames_list
-                        frames_list.trace_obj, None, frames_list.exc_type, frames_list.exc_desc, memo)
                     if frames_list is None or not frames_list:
                         break
 

src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_frame_utils.py

@@ -97,6 +97,8 @@ class FramesList(object):
         # This is to know whether an exception was extracted from a __cause__ or __context__.
         self.exc_context_msg = ''
 
+        self.chained_frames_list = None
+
     def append(self, frame):
         self._frames.append(frame)
 
@@ -128,7 +130,13 @@ class FramesList(object):
             lst.append('\n    ')
             lst.append(repr(frame))
             lst.append(',')
+
+        if self.chained_frames_list is not None:
+            lst.append('\n--- Chained ---\n')
+            lst.append(str(self.chained_frames_list))
+
         lst.append('\n)')
+
         return ''.join(lst)
 
     __str__ = __repr__
@@ -142,7 +150,8 @@ class _DummyFrameWrapper(object):
         self.f_back = f_back
         self.f_trace = None
         original_code = frame.f_code
-        self.f_code = FCode(original_code.co_name , original_code.co_filename)
+        name = original_code.co_name
+        self.f_code = FCode(name, original_code.co_filename)
 
     @property
     def f_locals(self):
@@ -152,6 +161,11 @@ class _DummyFrameWrapper(object):
     def f_globals(self):
         return self._base_frame.f_globals
 
+    def __str__(self):
+        return "<_DummyFrameWrapper, file '%s', line %s, %s" % (self.f_code.co_filename, self.f_lineno, self.f_code.co_name)
+
+    __repr__ = __str__
+
 
 _cause_message = (
     "\nThe above exception was the direct cause "
@@ -231,36 +245,6 @@ def create_frames_list_from_traceback(trace_obj, frame, exc_type, exc_desc, exce
         lst.append((tb.tb_frame, tb.tb_lineno))
         tb = tb.tb_next
 
-    curr = exc_desc
-    memo = set()
-    while True:
-        initial = curr
-        try:
-            curr = getattr(initial, '__cause__', None)
-        except Exception:
-            curr = None
-
-        if curr is None:
-            try:
-                curr = getattr(initial, '__context__', None)
-            except Exception:
-                curr = None
-
-        if curr is None or id(curr) in memo:
-            break
-
-        # The traceback module does this, so, let's play safe here too...
-        memo.add(id(curr))
-
-        tb = getattr(curr, '__traceback__', None)
-
-        while tb is not None:
-            # Note: we don't use the actual tb.tb_frame because if the cause of the exception
-            # uses the same frame object, the id(frame) would be the same and the frame_id_to_lineno
-            # would be wrong as the same frame needs to appear with 2 different lines.
-            lst.append((_DummyFrameWrapper(tb.tb_frame, tb.tb_lineno, None), tb.tb_lineno))
-            tb = tb.tb_next
-
     frames_list = None
 
     for tb_frame, tb_lineno in reversed(lst):
@@ -290,6 +274,18 @@ def create_frames_list_from_traceback(trace_obj, frame, exc_type, exc_desc, exce
         if len(frames_list) > 0:
             frames_list.current_frame = frames_list.last_frame()
 
+    curr = frames_list
+    memo = set()
+    memo.add(id(exc_desc))
+
+    while True:
+        chained = create_frames_list_from_exception_cause(None, None, None, curr.exc_desc, memo)
+        if chained is None:
+            break
+        else:
+            curr.chained_frames_list = chained
+            curr = chained
+
     return frames_list
 
 

src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_net_command_factory_json.py

@@ -230,7 +230,7 @@ class NetCommandFactoryJson(NetCommandFactory):
                     frames_list = pydevd_frame_utils.create_frames_list_from_frame(topmost_frame)
 
             for frame_id, frame, method_name, original_filename, filename_in_utf8, lineno, applied_mapping, show_as_current_frame in self._iter_visible_frames_info(
-                    py_db, frames_list
+                    py_db, frames_list, flatten_chained=True
                 ):
 
                 try:

src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_net_command_factory_xml.py

@@ -164,8 +164,10 @@ class NetCommandFactory(object):
         except:
             return self.make_error_message(0, get_exception_traceback_str())
 
-    def _iter_visible_frames_info(self, py_db, frames_list):
+    def _iter_visible_frames_info(self, py_db, frames_list, flatten_chained=False):
         assert frames_list.__class__ == FramesList
+        is_chained = False
+        while True:
             for frame in frames_list:
                 show_as_current_frame = frame is frames_list.current_frame
                 if frame.f_code is None:
@@ -177,6 +179,9 @@ class NetCommandFactory(object):
                     pydev_log.info('Frame without co_name: %s', frame)
                     continue  # IronPython sometimes does not have it!
 
+                if is_chained:
+                    method_name = '[Chained Exc: %s] %s' % (frames_list.exc_desc, method_name)
+
                 abs_path_real_path_and_base = get_abs_path_real_path_and_base_from_frame(frame)
                 if py_db.get_file_type(frame, abs_path_real_path_and_base) == py_db.PYDEV_FILE:
                     # Skip pydevd files.
@@ -192,6 +197,14 @@ class NetCommandFactory(object):
 
                 yield frame_id, frame, method_name, abs_path_real_path_and_base[0], new_filename_in_utf8, lineno, applied_mapping, show_as_current_frame
 
+            if not flatten_chained:
+                break
+
+            frames_list = frames_list.chained_frames_list
+            if frames_list is None or len(frames_list) == 0:
+                break
+            is_chained = True
+
     def make_thread_stack_str(self, py_db, frames_list):
         assert frames_list.__class__ == FramesList
         make_valid_xml_value = pydevd_xml.make_valid_xml_value
@@ -200,7 +213,7 @@ class NetCommandFactory(object):
 
         try:
             for frame_id, frame, method_name, _original_filename, filename_in_utf8, lineno, _applied_mapping, _show_as_current_frame in self._iter_visible_frames_info(
-                    py_db, frames_list
+                    py_db, frames_list, flatten_chained=True
                 ):
 
                 # print("file is ", filename_in_utf8)

src/debugpy/_vendored/pydevd/tests_python/test_debugger.py

@@ -1657,13 +1657,13 @@ def test_case_throw_exc_reason_xml(case_setup):
             name_and_lines.append((frame['name'], frame['line']))
 
         assert name_and_lines == [
-            ('method2', '2'),
-            ('method', '6'),
-            ('foobar', '16'),
-            ('handle', '10'),
-            ('foobar', '18'),
             ('foobar', '20'),
             ('<module>', '23'),
+            ('[Chained Exc: another while handling] foobar', '18'),
+            ('[Chained Exc: another while handling] handle', '10'),
+            ('[Chained Exc: TEST SUCEEDED] foobar', '16'),
+            ('[Chained Exc: TEST SUCEEDED] method', '6'),
+            ('[Chained Exc: TEST SUCEEDED] method2', '2'),
         ]
 
         hit = writer.wait_for_breakpoint_hit(REASON_UNCAUGHT_EXCEPTION)

src/debugpy/_vendored/pydevd/tests_python/test_debugger_json.py

@@ -751,7 +751,15 @@ def test_case_throw_exc_reason(case_setup):
         stack_frames = json_hit.stack_trace_response.body.stackFrames
         # Note that the additional context doesn't really appear in the stack
         # frames, only in the details.
-        assert [x['name'] for x in stack_frames] == ['foobar', '<module>']
+        assert [x['name'] for x in stack_frames] == [
+            'foobar',
+            '<module>',
+            '[Chained Exc: another while handling] foobar',
+            '[Chained Exc: another while handling] handle',
+            '[Chained Exc: TEST SUCEEDED] foobar',
+            '[Chained Exc: TEST SUCEEDED] method',
+            '[Chained Exc: TEST SUCEEDED] method2',
+        ]
 
         body = exc_info_response.body
         assert body.exceptionId.endswith('RuntimeError')
@@ -760,10 +768,16 @@ def test_case_throw_exc_reason(case_setup):
 
         # Check that we have all the lines (including the cause/context) in the stack trace.
         import re
-        lines_and_names = re.findall(r',\sline\s(\d+),\sin\s([\w|<|>]+)', body.details.stackTrace)
+        lines_and_names = re.findall(r',\sline\s(\d+),\sin\s(\[Chained Exception\]\s)?([\w|<|>]+)', body.details.stackTrace)
         assert lines_and_names == [
-            ('16', 'foobar'), ('6', 'method'), ('2', 'method2'), ('18', 'foobar'), ('10', 'handle'), ('20', 'foobar'), ('23', '<module>')
+            ('16', '', 'foobar'),
-        ]
+            ('6', '', 'method'),
+            ('2', '', 'method2'),
+            ('18', '', 'foobar'),
+            ('10', '', 'handle'),
+            ('20', '', 'foobar'),
+            ('23', '', '<module>'),
+        ], 'Did not find the expected names in:\n%s' % (body.details.stackTrace,)
 
         json_facade.write_continue()
 
@@ -802,7 +816,12 @@ def test_case_throw_exc_reason_shown(case_setup):
         stack_frames = json_hit.stack_trace_response.body.stackFrames
         # Note that the additional context doesn't really appear in the stack
         # frames, only in the details.
-        assert [x['name'] for x in stack_frames] == ['method', '<module>']
+        assert [x['name'] for x in stack_frames] == [
+            'method',
+            '<module>',
+            "[Chained Exc: 'foo'] method",
+            "[Chained Exc: 'foo'] method2",
+        ]
 
         body = exc_info_response.body
         assert body.exceptionId == 'Exception'
@@ -3323,7 +3342,7 @@ def test_exception_details(case_setup, max_frames):
         else:
             json_facade.write_launch(maxExceptionStackFrames=max_frames)
             min_expected_lines = 10
-            max_expected_lines = 21
+            max_expected_lines = 22
 
         json_facade.write_set_exception_breakpoints(['raised'])
 

src/debugpy/_vendored/pydevd/tests_python/test_frame_utils.py

@@ -0,0 +1,34 @@
+import sys
+from _pydevd_bundle.pydevd_constants import EXCEPTION_TYPE_USER_UNHANDLED
+
+
+def test_create_frames_list_from_traceback():
+
+    def method():
+        raise RuntimeError('first')
+
+    def method1():
+        try:
+            method()
+        except Exception as e:
+            raise RuntimeError('second') from e
+
+    def method2():
+        try:
+            method1()
+        except Exception as e:
+            raise RuntimeError('third') from e
+
+    try:
+        method2()
+    except Exception as e:
+        exc_type, exc_desc, trace_obj = sys.exc_info()
+        frame = sys._getframe()
+
+        from _pydevd_bundle.pydevd_frame_utils import create_frames_list_from_traceback
+        frames_list = create_frames_list_from_traceback(trace_obj, frame, exc_type, exc_desc, exception_type=EXCEPTION_TYPE_USER_UNHANDLED)
+        assert str(frames_list.exc_desc) == 'third'
+        assert str(frames_list.chained_frames_list.exc_desc) == 'second'
+        assert str(frames_list.chained_frames_list.chained_frames_list.exc_desc) == 'first'
+        assert frames_list.chained_frames_list.chained_frames_list.chained_frames_list is None
+

tests/debugpy/test_exception.py

@@ -354,7 +354,7 @@ def test_exception_stack(pyfile, target, run, max_frames):
         max_frames, (min_expected_lines, max_expected_lines) = {
             "all": (0, (100, 221)),
             "default": (None, (100, 221)),
-            10: (10, (10, 21)),
+            10: (10, (10, 22)),
         }[max_frames]
         if max_frames is not None:
             session.config["maxExceptionStackFrames"] = max_frames