Add setting to limit number of lines in stack for exception details. F…

…ixes #582 (#1309)

* Add maxExcpetionStackFrames setting

* Tests for maxExcpetionStackFrames setting

* Set default as all frames

* Address comments

* Fix merge issue

src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_api.py

@@ -126,12 +126,13 @@ def request_stack(self, py_db, seq, thread_id, fmt=None, timeout=.5):
  else:
  py_db.post_internal_command(internal_get_thread_stack, '*')
 
- def request_exception_info_json(self, py_db, request, thread_id):
+ def request_exception_info_json(self, py_db, request, thread_id, max_frames):
  py_db.post_method_as_internal_command(
  thread_id,
  internal_get_exception_details_json,
  request,
  thread_id,
+ max_frames,
  set_additional_thread_info=set_additional_thread_info,
  iter_visible_frames_info=py_db.cmd_factory._iter_visible_frames_info)
 

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

@@ -1077,7 +1077,7 @@ def internal_get_description(dbg, seq, thread_id, frame_id, expression):
  dbg.writer.add_command(cmd)
 
 
-def internal_get_exception_details_json(dbg, request, thread_id, set_additional_thread_info=None, iter_visible_frames_info=None):
+def internal_get_exception_details_json(dbg, request, thread_id, max_frames, set_additional_thread_info=None, iter_visible_frames_info=None):
  ''' Fetch exception details
  '''
  try:
@@ -1143,7 +1143,7 @@ def internal_get_exception_details_json(dbg, request, thread_id, set_additional_
  except:
  pass
 
- stack_str = ''.join(traceback.format_list(frames))
+ stack_str = ''.join(traceback.format_list(frames[-max_frames:]))
 
  # This is an extra bit of data used by Visual Studio
  source_path = frames[0][0] if frames else ''

src/ptvsd/_vendored/pydevd/_pydevd_bundle/pydevd_process_net_command_json.py

@@ -190,6 +190,8 @@ def _set_debug_options(self, py_db, args):
  args.get('options'),
  args.get('debugOptions'),
  )
+ self._debug_options['args'] = args
+
  debug_stdlib = self._debug_options.get('DEBUG_STDLIB', False)
  self.api.set_use_libraries_filter(py_db, not debug_stdlib)
 
@@ -491,8 +493,9 @@ def on_exceptioninfo_request(self, py_db, request):
  '''
  # : :type exception_into_arguments: ExceptionInfoArguments
  exception_into_arguments = request.arguments
- thread_id = exception_into_arguments.threadId
- self.api.request_exception_info_json(py_db, request, thread_id)
+ thread_id = exception_into_arguments.threadId 
+ max_frames = int(self._debug_options['args'].get('maxExceptionStackFrames', 0))
+ self.api.request_exception_info_json(py_db, request, thread_id, max_frames)
 
  def on_scopes_request(self, py_db, request):
  '''

src/ptvsd/_vendored/pydevd/tests_python/resources/_debugger_case_large_exception_stack.py

@@ -0,0 +1,11 @@
+def method1(n):
+ if n <= 0:
+ raise IndexError('foo')
+ method2(n-1)
+
+def method2(n):
+ method1(n-1)
+
+if __name__ == '__main__':
+ method1(100)
+ print('TEST SUCEEDED!')

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

@@ -1140,11 +1140,28 @@ def test_evaluate(case_setup):
  writer.finished_ok = True
 
 
-def test_exception_details(case_setup):
- with case_setup.test_file('_debugger_case_exceptions.py') as writer:
+@pytest.mark.parametrize('max_frames', ['default', 'all', 10]) # -1 = default, 0 = all, 10 = 10 frames
+def test_exception_details(case_setup, max_frames):
+ with case_setup.test_file('_debugger_case_large_exception_stack.py') as writer:
  json_facade = JsonFacade(writer)
 
  writer.write_set_protocol('http_json')
+ if max_frames == 'all':
+ json_facade.write_launch(maxExceptionStackFrames=0)
+ # trace back compresses repeated text
+ min_expected_lines = 100
+ max_expected_lines = 220
+ elif max_frames == 'default':
+ json_facade.write_launch()
+ # default is all frames
+ # trace back compresses repeated text
+ min_expected_lines = 100
+ max_expected_lines = 220
+ else:
+ json_facade.write_launch(maxExceptionStackFrames=max_frames)
+ min_expected_lines = 10
+ max_expected_lines = 21
+
  json_facade.write_set_exception_breakpoints(['raised'])
 
  json_facade.write_make_initial_run()
@@ -1157,6 +1174,8 @@ def test_exception_details(case_setup):
  assert body.exceptionId.endswith('IndexError')
  assert body.description == 'foo'
  assert body.details.kwargs['source'] == writer.TEST_FILE
+ stack_line_count = len(body.details.stackTrace.split('\n'))
+ assert min_expected_lines <= stack_line_count <= max_expected_lines
 
  json_facade.write_set_exception_breakpoints([]) # Don't stop on reraises.
  writer.write_run_thread(hit.thread_id)

tests/func/test_exception.py

@@ -9,7 +9,7 @@
 from tests.helpers import print, get_marked_line_numbers
 from tests.helpers.session import DebugSession
 from tests.helpers.timeline import Event
-from tests.helpers.pattern import ANY, Path
+from tests.helpers.pattern import ANY, Path, Regex
 
 
 @pytest.mark.parametrize('raised', ['raisedOn', 'raisedOff'])
@@ -344,3 +344,76 @@ def code_to_debug():
  session.send_request('continue').wait_for_response(freeze=False)
 
  session.wait_for_exit()
+
+
+@pytest.mark.parametrize('max_frames', ['default', 'all', 10])
+def test_exception_stack(pyfile, run_as, start_method, max_frames):
+ @pyfile
+ def code_to_debug():
+ from dbgimporter import import_and_enable_debugger
+ import_and_enable_debugger()
+ def do_something(n):
+ if n <= 0:
+ raise ArithmeticError('bad code') # @unhandled
+ do_something2(n - 1)
+
+ def do_something2(n):
+ do_something(n-1)
+
+ do_something(100)
+
+ if max_frames == 'all':
+ # trace back compresses repeated text
+ min_expected_lines = 100
+ max_expected_lines = 220
+ args = {'maxExceptionStackFrames': 0}
+ elif max_frames == 'default':
+ # default is all frames
+ min_expected_lines = 100
+ max_expected_lines = 220
+ args = {}
+ else:
+ min_expected_lines = 10
+ max_expected_lines = 21
+ args = {'maxExceptionStackFrames': 10}
+
+ line_numbers = get_marked_line_numbers(code_to_debug)
+ with DebugSession() as session:
+ session.initialize(
+ target=(run_as, code_to_debug),
+ start_method=start_method,
+ ignore_unobserved=[Event('continued')],
+ expected_returncode=ANY.int,
+ args=args,
+ )
+ session.send_request('setExceptionBreakpoints', {
+ 'filters': ['uncaught']
+ }).wait_for_response()
+ session.start_debugging()
+
+ hit = session.wait_for_thread_stopped(reason='exception')
+ frames = hit.stacktrace.body['stackFrames']
+ assert frames[0]['line'] == line_numbers['unhandled']
+
+ resp_exc_info = session.send_request('exceptionInfo', {
+ 'threadId': hit.thread_id
+ }).wait_for_response()
+
+ expected = ANY.dict_with({
+ 'exceptionId': Regex('ArithmeticError'),
+ 'description': 'bad code',
+ 'breakMode': 'unhandled',
+ 'details': ANY.dict_with({
+ 'typeName': Regex('ArithmeticError'),
+ 'message': 'bad code',
+ 'source': Path(code_to_debug),
+ }),
+ })
+ assert resp_exc_info.body == expected
+ stack_str = resp_exc_info.body['details']['stackTrace']
+ stack_line_count = len(stack_str.split('\n'))
+ assert min_expected_lines <= stack_line_count <= max_expected_lines
+
+ session.send_request('continue').wait_for_response(freeze=False)
+
+ session.wait_for_exit()

tests/helpers/session.py

@@ -46,6 +46,7 @@ def __init__(self, start_method='launch', ptvsd_port=None, pid=None):
 
  self.target = ('code', 'print("OK")')
  self.start_method = start_method
+ self.start_method_args = {}
  self.no_debug = False
  self.ptvsd_port = ptvsd_port or PTVSD_PORT
  self.multiprocess = False
@@ -230,6 +231,7 @@ def _setup_session(self, **kwargs):
  ] + kwargs.pop('ignore_unobserved', [])
 
  self.env.update(kwargs.pop('env', {}))
+ self.start_method_args.update(kwargs.pop('args', {}))
 
  self.path_mappings += kwargs.pop('path_mappings', [])
  self.debug_options += kwargs.pop('debug_options', [])
@@ -497,14 +499,14 @@ def handshake(self):
  self.wait_for_next(Event('initialized', {}))
 
  request = 'launch' if self.start_method == 'launch' else 'attach'
- args = {
+ self.start_method_args.update({
  'debugOptions': self.debug_options,
  'pathMappings': self.path_mappings,
  'rules': self.rules,
- }
+ })
  if self.success_exitcodes is not None:
- args['successExitCodes'] = self.success_exitcodes
- self.send_request(request, args).wait_for_response()
+ self.start_method_args['successExitCodes'] = self.success_exitcodes
+ self.send_request(request, self.start_method_args).wait_for_response()
 
  if not self.no_debug:
  # Issue 'threads' so that we get the 'thread' event for the main thread now,