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CarreauCarreau
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Add support for both context and cause.
It should be rare to have both, but now we can explore the full tree of exception. We do a Breadth first traversal of the exception cause/context to be able to jump to any of those. The UI is not optimal, but I'm unsure if there is a better way to show it. I'm thinking a tree, but that might be overwhelming.
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2 files changed

+113
-14
lines changed

2 files changed

+113
-14
lines changed

‎Lib/pdb.py‎

Lines changed: 13 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -207,7 +207,7 @@ def namespace(self):
207207

208208
class Pdb(bdb.Bdb, cmd.Cmd):
209209
_chained_exceptions = []
210-
_chained_exception_index = 0
210+
_chained_exception_index = None
211211

212212
_previous_sigint_handler = None
213213

@@ -422,12 +422,20 @@ def interaction(self, frame, tb_or_exc):
422422
if isinstance(tb_or_exc, BaseException):
423423
tb_or_exc, exception = tb_or_exc.__traceback__, tb_or_exc
424424
self._chained_exceptions = [exception]
425-
current = exception
426-
while current := current.__context__:
427-
self._chained_exception_index += 1
428-
self._chained_exceptions.insert(0, current)
425+
self._chained_exception_index = 0
426+
open_list = [exception]
427+
while open_list:
428+
current = open_list.pop(0)
429+
for ex_type in ["__cause__", "__context__"]:
430+
next_ex = getattr(current, ex_type, None)
431+
if next_ex and next_ex not in self._chained_exceptions:
432+
open_list.append(next_ex)
433+
self._chained_exception_index += 1
434+
self._chained_exceptions.insert(0, next_ex)
435+
429436
else:
430437
self._chained_exceptions = []
438+
self._chained_exception_index = None
431439

432440
if Pdb._previous_sigint_handler:
433441
try:

‎Lib/test/test_pdb.py‎

Lines changed: 100 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -827,7 +827,7 @@ def test_convenience_variables():
827827
"""
828828

829829

830-
def test_post_mortem_chained():
830+
def test_post_mortem_simple_chained():
831831
"""Test post mortem traceback debugging of chained exception
832832
833833
>>> def test_function_2():
@@ -870,40 +870,131 @@ def test_post_mortem_chained():
870870
... except ZeroDivisionError:
871871
... print('Correctly reraised.')
872872
Exception!
873-
> <doctest test.test_pdb.test_post_mortem_chained[1]>(5)test_function_reraise()
873+
> <doctest test.test_pdb.test_post_mortem_simple_chained[1]>(5)test_function_reraise()
874874
-> raise ZeroDivisionError('reraised') from e
875875
(Pdb) exceptions
876876
0 ZeroDivisionError('division by zero')
877877
> 1 ZeroDivisionError('reraised')
878878
(Pdb) exceptions 0
879-
> <doctest test.test_pdb.test_post_mortem_chained[0]>(3)test_function_2()
879+
> <doctest test.test_pdb.test_post_mortem_simple_chained[0]>(3)test_function_2()
880880
-> 1/0
881881
(Pdb) up
882-
> <doctest test.test_pdb.test_post_mortem_chained[1]>(3)test_function_reraise()
882+
> <doctest test.test_pdb.test_post_mortem_simple_chained[1]>(3)test_function_reraise()
883883
-> test_function_2()
884884
(Pdb) down
885-
> <doctest test.test_pdb.test_post_mortem_chained[0]>(3)test_function_2()
885+
> <doctest test.test_pdb.test_post_mortem_simple_chained[0]>(3)test_function_2()
886886
-> 1/0
887887
(Pdb) exceptions 1
888-
> <doctest test.test_pdb.test_post_mortem_chained[1]>(5)test_function_reraise()
888+
> <doctest test.test_pdb.test_post_mortem_simple_chained[1]>(5)test_function_reraise()
889889
-> raise ZeroDivisionError('reraised') from e
890890
(Pdb) up
891-
> <doctest test.test_pdb.test_post_mortem_chained[2]>(5)test_function()
891+
> <doctest test.test_pdb.test_post_mortem_simple_chained[2]>(5)test_function()
892892
-> test_function_reraise()
893893
(Pdb) down
894-
> <doctest test.test_pdb.test_post_mortem_chained[1]>(5)test_function_reraise()
894+
> <doctest test.test_pdb.test_post_mortem_simple_chained[1]>(5)test_function_reraise()
895895
-> raise ZeroDivisionError('reraised') from e
896896
(Pdb) exceptions -1
897897
*** No exception with that number
898898
(Pdb) exceptions 3
899899
*** No exception with that number
900900
(Pdb) up
901-
> <doctest test.test_pdb.test_post_mortem_chained[2]>(5)test_function()
901+
> <doctest test.test_pdb.test_post_mortem_simple_chained[2]>(5)test_function()
902902
-> test_function_reraise()
903903
(Pdb) exit
904904
"""
905905

906906

907+
def test_post_mortem_context_and_cause():
908+
"""Test post mortem traceback debugging of chained exception
909+
910+
>>> def cause():
911+
... try:
912+
... raise ValueError("Cause Leaf")
913+
... except Exception as e:
914+
... raise ValueError("With Cause") from e
915+
916+
>>> def context():
917+
... try:
918+
... raise ValueError("Context Leaf")
919+
... except Exception as e:
920+
... raise ValueError("With Context") from e
921+
922+
>>> def main():
923+
... try:
924+
... context()
925+
... except Exception as e1:
926+
... try:
927+
... cause()
928+
... except Exception as e2:
929+
... ex = e2
930+
... raise ValueError("With Context and With Cause") from ex
931+
932+
>>> def test_function():
933+
... import pdb;
934+
... instance = pdb.Pdb(nosigint=True, readrc=False)
935+
... try:
936+
... main()
937+
... except Exception as e:
938+
... # same as pdb.post_mortem(e), but with custom pdb instance.
939+
... instance.reset()
940+
... instance.interaction(None, e)
941+
942+
>>> with PdbTestInput([ # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
943+
... 'exceptions',
944+
... 'exceptions 2',
945+
... 'up',
946+
... 'down',
947+
... 'exceptions 3',
948+
... 'up',
949+
... 'down',
950+
... 'exceptions 4',
951+
... 'up',
952+
... 'down',
953+
... 'exit',
954+
... ]):
955+
... try:
956+
... test_function()
957+
... except ValueError:
958+
... print('Correctly reraised.')
959+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[2]>(9)main()
960+
-> raise ValueError("With Context and With Cause") from ex
961+
(Pdb) exceptions
962+
0 ValueError('Cause Leaf')
963+
1 ValueError('Context Leaf')
964+
2 ValueError('With Cause')
965+
3 ValueError('With Context')
966+
> 4 ValueError('With Context and With Cause')
967+
(Pdb) exceptions 2
968+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[0]>(5)cause()
969+
-> raise ValueError("With Cause") from e
970+
(Pdb) up
971+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[2]>(6)main()
972+
-> cause()
973+
(Pdb) down
974+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[0]>(5)cause()
975+
-> raise ValueError("With Cause") from e
976+
(Pdb) exceptions 3
977+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[1]>(5)context()
978+
-> raise ValueError("With Context") from e
979+
(Pdb) up
980+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[2]>(3)main()
981+
-> context()
982+
(Pdb) down
983+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[1]>(5)context()
984+
-> raise ValueError("With Context") from e
985+
(Pdb) exceptions 4
986+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[2]>(9)main()
987+
-> raise ValueError("With Context and With Cause") from ex
988+
(Pdb) up
989+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[3]>(5)test_function()
990+
-> main()
991+
(Pdb) down
992+
> <doctest test.test_pdb.test_post_mortem_context_and_cause[2]>(9)main()
993+
-> raise ValueError("With Context and With Cause") from ex
994+
(Pdb) exit
995+
"""
996+
997+
907998
def test_post_mortem():
908999
"""Test post mortem traceback debugging.
9091000

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