import sys import traceback from typing import NoReturn from urllib.error import HTTPError import pytest from _pytest.capture import CaptureFixture from _pytest.fixtures import SubRequest from _pytest.monkeypatch import MonkeyPatch from exceptiongroup import ExceptionGroup def raise_excgroup() -> NoReturn: exceptions = [] try: raise ValueError("foo") except ValueError as exc: exceptions.append(exc) try: raise RuntimeError("bar") except RuntimeError as exc: exc.__notes__ = ["Note from bar handler"] exceptions.append(exc) exc = ExceptionGroup("test message", exceptions) exc.add_note("Displays notes attached to the group too") raise exc @pytest.fixture( params=[ pytest.param(True, id="patched"), pytest.param( False, id="unpatched", marks=[ pytest.mark.skipif( sys.version_info >= (3, 11), reason="No patching is done on Python >= 3.11", ) ], ), ], ) def patched(request: SubRequest) -> bool: return request.param @pytest.fixture( params=[pytest.param(False, id="newstyle"), pytest.param(True, id="oldstyle")] ) def old_argstyle(request: SubRequest) -> bool: return request.param def test_exceptionhook(capsys: CaptureFixture) -> None: try: raise_excgroup() except ExceptionGroup as exc: sys.excepthook(type(exc), exc, exc.__traceback__) local_lineno = test_exceptionhook.__code__.co_firstlineno lineno = raise_excgroup.__code__.co_firstlineno module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." underline_suffix = ( "" if sys.version_info < (3, 13) else "\n | ~~~~~~~~~~~~~~^^" ) output = capsys.readouterr().err assert output == ( f"""\ + Exception Group Traceback (most recent call last): | File "{__file__}", line {local_lineno + 2}, in test_exceptionhook | raise_excgroup(){underline_suffix} | File "{__file__}", line {lineno + 15}, in raise_excgroup | raise exc | {module_prefix}ExceptionGroup: test message (2 sub-exceptions) | Displays notes attached to the group too +-+---------------- 1 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 3}, in raise_excgroup | raise ValueError("foo") | ValueError: foo +---------------- 2 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 8}, in raise_excgroup | raise RuntimeError("bar") | RuntimeError: bar | Note from bar handler +------------------------------------ """ ) def test_exceptiongroup_as_cause(capsys: CaptureFixture) -> None: try: raise Exception() from ExceptionGroup("", (Exception(),)) except Exception as exc: sys.excepthook(type(exc), exc, exc.__traceback__) lineno = test_exceptiongroup_as_cause.__code__.co_firstlineno module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." output = capsys.readouterr().err assert output == ( f"""\ | {module_prefix}ExceptionGroup: (1 sub-exception) +-+---------------- 1 ---------------- | Exception +------------------------------------ The above exception was the direct cause of the following exception: Traceback (most recent call last): File "{__file__}", line {lineno + 2}, in test_exceptiongroup_as_cause raise Exception() from ExceptionGroup("", (Exception(),)) Exception """ ) def test_exceptiongroup_loop(capsys: CaptureFixture) -> None: e0 = Exception("e0") eg0 = ExceptionGroup("eg0", (e0,)) eg1 = ExceptionGroup("eg1", (eg0,)) try: raise eg0 from eg1 except ExceptionGroup as exc: sys.excepthook(type(exc), exc, exc.__traceback__) lineno = test_exceptiongroup_loop.__code__.co_firstlineno + 6 module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." output = capsys.readouterr().err assert output == ( f"""\ | {module_prefix}ExceptionGroup: eg1 (1 sub-exception) +-+---------------- 1 ---------------- | Exception Group Traceback (most recent call last): | File "{__file__}", line {lineno}, in test_exceptiongroup_loop | raise eg0 from eg1 | {module_prefix}ExceptionGroup: eg0 (1 sub-exception) +-+---------------- 1 ---------------- | Exception: e0 +------------------------------------ The above exception was the direct cause of the following exception: + Exception Group Traceback (most recent call last): | File "{__file__}", line {lineno}, in test_exceptiongroup_loop | raise eg0 from eg1 | {module_prefix}ExceptionGroup: eg0 (1 sub-exception) +-+---------------- 1 ---------------- | Exception: e0 +------------------------------------ """ ) def test_exceptionhook_format_exception_only(capsys: CaptureFixture) -> None: try: raise_excgroup() except ExceptionGroup as exc: sys.excepthook(type(exc), exc, exc.__traceback__) local_lineno = test_exceptionhook_format_exception_only.__code__.co_firstlineno lineno = raise_excgroup.__code__.co_firstlineno module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." underline_suffix = ( "" if sys.version_info < (3, 13) else "\n | ~~~~~~~~~~~~~~^^" ) output = capsys.readouterr().err assert output == ( f"""\ + Exception Group Traceback (most recent call last): | File "{__file__}", line {local_lineno + 2}, in \ test_exceptionhook_format_exception_only | raise_excgroup(){underline_suffix} | File "{__file__}", line {lineno + 15}, in raise_excgroup | raise exc | {module_prefix}ExceptionGroup: test message (2 sub-exceptions) | Displays notes attached to the group too +-+---------------- 1 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 3}, in raise_excgroup | raise ValueError("foo") | ValueError: foo +---------------- 2 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 8}, in raise_excgroup | raise RuntimeError("bar") | RuntimeError: bar | Note from bar handler +------------------------------------ """ ) def test_formatting_syntax_error(capsys: CaptureFixture) -> None: try: exec("//serser") except SyntaxError as exc: sys.excepthook(type(exc), exc, exc.__traceback__) if sys.version_info >= (3, 10): underline = "\n ^^" elif sys.version_info >= (3, 8): underline = "\n ^" else: underline = "\n ^" lineno = test_formatting_syntax_error.__code__.co_firstlineno underline_suffix = "" if sys.version_info < (3, 13) else "\n ~~~~^^^^^^^^^^^^" output = capsys.readouterr().err assert output == ( f"""\ Traceback (most recent call last): File "{__file__}", line {lineno + 2}, \ in test_formatting_syntax_error exec("//serser"){underline_suffix} File "", line 1 //serser{underline} SyntaxError: invalid syntax """ ) def test_format_exception( patched: bool, old_argstyle: bool, monkeypatch: MonkeyPatch ) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import format_exception exceptions = [] try: raise ValueError("foo") except ValueError as exc: exceptions.append(exc) try: raise RuntimeError("bar") except RuntimeError as exc: exc.__notes__ = ["Note from bar handler"] exceptions.append(exc) try: raise_excgroup() except ExceptionGroup as exc: if old_argstyle: lines = format_exception(type(exc), exc, exc.__traceback__) else: lines = format_exception(exc) local_lineno = test_format_exception.__code__.co_firstlineno lineno = raise_excgroup.__code__.co_firstlineno assert isinstance(lines, list) module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." underline_suffix = ( "" if sys.version_info < (3, 13) else "\n | ~~~~~~~~~~~~~~^^" ) assert "".join(lines) == ( f"""\ + Exception Group Traceback (most recent call last): | File "{__file__}", line {local_lineno + 25}, in test_format_exception | raise_excgroup(){underline_suffix} | File "{__file__}", line {lineno + 15}, in raise_excgroup | raise exc | {module_prefix}ExceptionGroup: test message (2 sub-exceptions) | Displays notes attached to the group too +-+---------------- 1 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 3}, in raise_excgroup | raise ValueError("foo") | ValueError: foo +---------------- 2 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 8}, in raise_excgroup | raise RuntimeError("bar") | RuntimeError: bar | Note from bar handler +------------------------------------ """ ) def test_format_nested(monkeypatch: MonkeyPatch) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import format_exception def raise_exc(max_level: int, level: int = 1) -> NoReturn: if level == max_level: raise Exception(f"LEVEL_{level}") else: try: raise_exc(max_level, level + 1) except Exception: raise Exception(f"LEVEL_{level}") try: raise_exc(3) except Exception as exc: lines = format_exception(type(exc), exc, exc.__traceback__) underline_suffix1 = ( "" if sys.version_info < (3, 13) else "\n ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^" ) underline_suffix2 = "" if sys.version_info < (3, 13) else "\n ~~~~~~~~~^^^" local_lineno = test_format_nested.__code__.co_firstlineno + 20 raise_exc_lineno1 = raise_exc.__code__.co_firstlineno + 2 raise_exc_lineno2 = raise_exc.__code__.co_firstlineno + 5 raise_exc_lineno3 = raise_exc.__code__.co_firstlineno + 7 assert isinstance(lines, list) assert "".join(lines) == ( f"""\ Traceback (most recent call last): File "{__file__}", line {raise_exc_lineno2}, in raise_exc raise_exc(max_level, level + 1){underline_suffix1} File "{__file__}", line {raise_exc_lineno1}, in raise_exc raise Exception(f"LEVEL_{{level}}") Exception: LEVEL_3 During handling of the above exception, another exception occurred: Traceback (most recent call last): File "{__file__}", line {raise_exc_lineno2}, in raise_exc raise_exc(max_level, level + 1){underline_suffix1} File "{__file__}", line {raise_exc_lineno3}, in raise_exc raise Exception(f"LEVEL_{{level}}") Exception: LEVEL_2 During handling of the above exception, another exception occurred: Traceback (most recent call last): File "{__file__}", line {local_lineno}, in test_format_nested raise_exc(3){underline_suffix2} File "{__file__}", line {raise_exc_lineno3}, in raise_exc raise Exception(f"LEVEL_{{level}}") Exception: LEVEL_1 """ ) def test_format_exception_only( patched: bool, old_argstyle: bool, monkeypatch: MonkeyPatch ) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import format_exception_only try: raise_excgroup() except ExceptionGroup as exc: if old_argstyle: output = format_exception_only(type(exc), exc) else: output = format_exception_only(exc) module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." assert output == [ f"{module_prefix}ExceptionGroup: test message (2 sub-exceptions)\n", "Displays notes attached to the group too\n", ] def test_print_exception( patched: bool, old_argstyle: bool, monkeypatch: MonkeyPatch, capsys: CaptureFixture ) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import print_exception try: raise_excgroup() except ExceptionGroup as exc: if old_argstyle: print_exception(type(exc), exc, exc.__traceback__) else: print_exception(exc) local_lineno = test_print_exception.__code__.co_firstlineno lineno = raise_excgroup.__code__.co_firstlineno module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." underline_suffix = ( "" if sys.version_info < (3, 13) else "\n | ~~~~~~~~~~~~~~^^" ) output = capsys.readouterr().err assert output == ( f"""\ + Exception Group Traceback (most recent call last): | File "{__file__}", line {local_lineno + 13}, in test_print_exception | raise_excgroup(){underline_suffix} | File "{__file__}", line {lineno + 15}, in raise_excgroup | raise exc | {module_prefix}ExceptionGroup: test message (2 sub-exceptions) | Displays notes attached to the group too +-+---------------- 1 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 3}, in raise_excgroup | raise ValueError("foo") | ValueError: foo +---------------- 2 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 8}, in raise_excgroup | raise RuntimeError("bar") | RuntimeError: bar | Note from bar handler +------------------------------------ """ ) def test_print_exc( patched: bool, monkeypatch: MonkeyPatch, capsys: CaptureFixture ) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import print_exc try: raise_excgroup() except ExceptionGroup: print_exc() local_lineno = test_print_exc.__code__.co_firstlineno lineno = raise_excgroup.__code__.co_firstlineno module_prefix = "" if sys.version_info >= (3, 11) else "exceptiongroup." underline_suffix = ( "" if sys.version_info < (3, 13) else "\n | ~~~~~~~~~~~~~~^^" ) output = capsys.readouterr().err assert output == ( f"""\ + Exception Group Traceback (most recent call last): | File "{__file__}", line {local_lineno + 13}, in test_print_exc | raise_excgroup(){underline_suffix} | File "{__file__}", line {lineno + 15}, in raise_excgroup | raise exc | {module_prefix}ExceptionGroup: test message (2 sub-exceptions) | Displays notes attached to the group too +-+---------------- 1 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 3}, in raise_excgroup | raise ValueError("foo") | ValueError: foo +---------------- 2 ---------------- | Traceback (most recent call last): | File "{__file__}", line {lineno + 8}, in raise_excgroup | raise RuntimeError("bar") | RuntimeError: bar | Note from bar handler +------------------------------------ """ ) @pytest.mark.skipif( not hasattr(NameError, "name") or sys.version_info[:2] == (3, 11), reason="only works if NameError exposes the missing name", ) def test_nameerror_suggestions( patched: bool, monkeypatch: MonkeyPatch, capsys: CaptureFixture ) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import print_exc try: folder except NameError: print_exc() output = capsys.readouterr().err assert "Did you mean" in output and "'filter'?" in output @pytest.mark.skipif( not hasattr(AttributeError, "name") or sys.version_info[:2] == (3, 11), reason="only works if AttributeError exposes the missing name", ) def test_nameerror_suggestions_in_group( patched: bool, monkeypatch: MonkeyPatch, capsys: CaptureFixture ) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import print_exception try: [].attend except AttributeError as e: eg = ExceptionGroup("a", [e]) print_exception(eg) output = capsys.readouterr().err assert "Did you mean" in output and "'append'?" in output def test_bug_suggestions_attributeerror_no_obj( patched: bool, monkeypatch: MonkeyPatch, capsys: CaptureFixture ) -> None: if not patched: # Block monkey patching, then force the module to be re-imported del sys.modules["traceback"] del sys.modules["exceptiongroup"] del sys.modules["exceptiongroup._formatting"] monkeypatch.setattr(sys, "excepthook", lambda *args: sys.__excepthook__(*args)) from exceptiongroup import print_exception class NamedAttributeError(AttributeError): def __init__(self, name: str) -> None: self.name: str = name try: raise NamedAttributeError(name="mykey") except AttributeError as e: print_exception(e) # does not crash output = capsys.readouterr().err assert "NamedAttributeError" in output def test_works_around_httperror_bug(): # See https://github.com/python/cpython/issues/98778 in Python <= 3.9 err = HTTPError("url", 405, "METHOD NOT ALLOWED", None, None) traceback.TracebackException(type(err), err, None)