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merged 2 commits into from
Aug 7, 2024
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gh-122478: Remove internal frames from tracebacks in REPL #122528

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gh-122478: Remove internal frames from tracebacks in REPL
serhiy-storchaka Jul 31, 2024
57d0770
Simply remove the top frame for run-time errors.
serhiy-storchaka Aug 1, 2024
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90 changes: 44 additions & 46 deletions Lib/code.py
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Original file line number Diff line number Diff line change
Expand Up @@ -107,29 +107,21 @@ def showsyntaxerror(self, filename=None, **kwargs):

"""
colorize = kwargs.pop('colorize', False)
type, value, tb = sys.exc_info()
sys.last_exc = value
sys.last_type = type
sys.last_value = value
sys.last_traceback = tb
if filename and type is SyntaxError:
# Work hard to stuff the correct filename in the exception
try:
msg, (dummy_filename, lineno, offset, line) = value.args
except ValueError:
# Not the format we expect; leave it alone
pass
else:
# Stuff in the right filename
value = SyntaxError(msg, (filename, lineno, offset, line))
sys.last_exc = sys.last_value = value
if sys.excepthook is sys.__excepthook__:
lines = traceback.format_exception_only(type, value, colorize=colorize)
self.write(''.join(lines))
else:
# If someone has set sys.excepthook, we let that take precedence
# over self.write
self._call_excepthook(type, value, tb)
try:
typ, value, tb = sys.exc_info()
if filename and typ is SyntaxError:
# Work hard to stuff the correct filename in the exception
try:
msg, (dummy_filename, lineno, offset, line) = value.args
except ValueError:
# Not the format we expect; leave it alone
pass
else:
# Stuff in the right filename
value = SyntaxError(msg, (filename, lineno, offset, line))
self._showtraceback(typ, value, None, colorize)
finally:
typ = value = tb = None

def showtraceback(self, **kwargs):
"""Display the exception that just occurred.
Expand All @@ -140,32 +132,38 @@ def showtraceback(self, **kwargs):

"""
colorize = kwargs.pop('colorize', False)
sys.last_type, sys.last_value, last_tb = ei = sys.exc_info()
sys.last_traceback = last_tb
sys.last_exc = ei[1]
try:
if sys.excepthook is sys.__excepthook__:
lines = traceback.format_exception(ei[0], ei[1], last_tb.tb_next, colorize=colorize)
self.write(''.join(lines))
else:
# If someone has set sys.excepthook, we let that take precedence
# over self.write
self._call_excepthook(ei[0], ei[1], last_tb)
typ, value, tb = sys.exc_info()
# Remove internal frames (in modules code and codeop) from traceback.
while tb and tb.tb_frame.f_globals.get('__name__') in ('code', 'codeop'):
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unittest's _clean_tracebacks() also looks at the chained exceptions.

Maybe it makes sense to implement this in the traceback module, and reuse?

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Actually, even this loop is an overpower on one side and not enough on other side. I initially added it to handle both compile-time (this is why copeop) and run-time errors. But then I have found that compile-time errors should not have a traceback at all.

Now I see that we should just remove one level from a traceback -- the one that refers to the code calls exec(). This is also necessary for IDLE which overrides runcode() -- in this case the top frame is in the idlelib.pyshell module.

This will not work if the code calls exec() not directly but via wrapper. Ideally we should find the frame that calls exec() (or eval()) and drop it and above frames, but there is no easy way to do this. It would help if exec() and eval() add a special marker in the traceback, but this would be a new feature.

tb = tb.tb_next
self._showtraceback(typ, value, tb, colorize)
finally:
last_tb = ei = None
typ = value = tb = None

def _call_excepthook(self, typ, value, tb):
try:
sys.excepthook(typ, value, tb)
except SystemExit:
raise
except BaseException as e:
e.__context__ = None
print('Error in sys.excepthook:', file=sys.stderr)
sys.__excepthook__(type(e), e, e.__traceback__.tb_next)
print(file=sys.stderr)
print('Original exception was:', file=sys.stderr)
sys.__excepthook__(typ, value, tb)
def _showtraceback(self, typ, value, tb, colorize):
sys.last_type = typ
sys.last_traceback = tb
sys.last_exc = sys.last_value = value = value.with_traceback(tb)
if sys.excepthook is sys.__excepthook__:
lines = traceback.format_exception(typ, value, tb,
colorize=colorize)
self.write(''.join(lines))
else:
# If someone has set sys.excepthook, we let that take precedence
# over self.write
try:
sys.excepthook(typ, value, tb)
except SystemExit:
raise
except BaseException as e:
e.__context__ = None
e = e.with_traceback(e.__traceback__.tb_next)
print('Error in sys.excepthook:', file=sys.stderr)
sys.__excepthook__(type(e), e, e.__traceback__)
print(file=sys.stderr)
print('Original exception was:', file=sys.stderr)
sys.__excepthook__(typ, value, tb)

def write(self, data):
"""Write a string.
Expand Down
125 changes: 117 additions & 8 deletions Lib/test/test_code_module.py
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
"Test InteractiveConsole and InteractiveInterpreter from code module"
import sys
import traceback
import unittest
from textwrap import dedent
from contextlib import ExitStack
Expand Down Expand Up @@ -30,6 +31,7 @@ def mock_sys(self):


class TestInteractiveConsole(unittest.TestCase, MockSys):
maxDiff = None

def setUp(self):
self.console = code.InteractiveConsole()
Expand Down Expand Up @@ -61,21 +63,118 @@ def test_console_stderr(self):
raise AssertionError("no console stdout")

def test_syntax_error(self):
self.infunc.side_effect = ["undefined", EOFError('Finished')]
self.infunc.side_effect = ["def f():",
" x = ?",
"",
EOFError('Finished')]
self.console.interact()
for call in self.stderr.method_calls:
if 'NameError' in ''.join(call[1]):
break
else:
raise AssertionError("No syntax error from console")
output = ''.join(''.join(call[1]) for call in self.stderr.method_calls)
output = output[output.index('(InteractiveConsole)'):]
output = output[:output.index('\nnow exiting')]
self.assertEqual(output.splitlines()[1:], [
' File "<console>", line 2',
' x = ?',
' ^',
'SyntaxError: invalid syntax'])
self.assertIs(self.sysmod.last_type, SyntaxError)
self.assertIs(type(self.sysmod.last_value), SyntaxError)
self.assertIsNone(self.sysmod.last_traceback)
self.assertIsNone(self.sysmod.last_value.__traceback__)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)

def test_indentation_error(self):
self.infunc.side_effect = [" 1", EOFError('Finished')]
self.console.interact()
output = ''.join(''.join(call[1]) for call in self.stderr.method_calls)
output = output[output.index('(InteractiveConsole)'):]
output = output[:output.index('\nnow exiting')]
self.assertEqual(output.splitlines()[1:], [
' File "<console>", line 1',
' 1',
'IndentationError: unexpected indent'])
self.assertIs(self.sysmod.last_type, IndentationError)
self.assertIs(type(self.sysmod.last_value), IndentationError)
self.assertIsNone(self.sysmod.last_traceback)
self.assertIsNone(self.sysmod.last_value.__traceback__)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)

def test_unicode_error(self):
self.infunc.side_effect = ["'\ud800'", EOFError('Finished')]
self.console.interact()
output = ''.join(''.join(call[1]) for call in self.stderr.method_calls)
output = output[output.index('(InteractiveConsole)'):]
output = output[output.index('\n') + 1:]
self.assertTrue(output.startswith('UnicodeEncodeError: '), output)
self.assertIs(self.sysmod.last_type, UnicodeEncodeError)
self.assertIs(type(self.sysmod.last_value), UnicodeEncodeError)
self.assertIsNone(self.sysmod.last_traceback)
self.assertIsNone(self.sysmod.last_value.__traceback__)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)

def test_sysexcepthook(self):
self.infunc.side_effect = ["raise ValueError('')",
self.infunc.side_effect = ["def f():",
" raise ValueError('BOOM!')",
"",
"f()",
EOFError('Finished')]
hook = mock.Mock()
self.sysmod.excepthook = hook
self.console.interact()
self.assertTrue(hook.called)
hook.assert_called()
hook.assert_called_with(self.sysmod.last_type,
self.sysmod.last_value,
self.sysmod.last_traceback)
self.assertIs(self.sysmod.last_type, ValueError)
self.assertIs(type(self.sysmod.last_value), ValueError)
self.assertIs(self.sysmod.last_traceback, self.sysmod.last_value.__traceback__)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)
self.assertEqual(traceback.format_exception(self.sysmod.last_exc), [
'Traceback (most recent call last):\n',
' File "<console>", line 1, in <module>\n',
' File "<console>", line 2, in f\n',
'ValueError: BOOM!\n'])

def test_sysexcepthook_syntax_error(self):
self.infunc.side_effect = ["def f():",
" x = ?",
"",
EOFError('Finished')]
hook = mock.Mock()
self.sysmod.excepthook = hook
self.console.interact()
hook.assert_called()
hook.assert_called_with(self.sysmod.last_type,
self.sysmod.last_value,
self.sysmod.last_traceback)
self.assertIs(self.sysmod.last_type, SyntaxError)
self.assertIs(type(self.sysmod.last_value), SyntaxError)
self.assertIsNone(self.sysmod.last_traceback)
self.assertIsNone(self.sysmod.last_value.__traceback__)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)
self.assertEqual(traceback.format_exception(self.sysmod.last_exc), [
' File "<console>", line 2\n',
' x = ?\n',
' ^\n',
'SyntaxError: invalid syntax\n'])

def test_sysexcepthook_indentation_error(self):
self.infunc.side_effect = [" 1", EOFError('Finished')]
hook = mock.Mock()
self.sysmod.excepthook = hook
self.console.interact()
hook.assert_called()
hook.assert_called_with(self.sysmod.last_type,
self.sysmod.last_value,
self.sysmod.last_traceback)
self.assertIs(self.sysmod.last_type, IndentationError)
self.assertIs(type(self.sysmod.last_value), IndentationError)
self.assertIsNone(self.sysmod.last_traceback)
self.assertIsNone(self.sysmod.last_value.__traceback__)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)
self.assertEqual(traceback.format_exception(self.sysmod.last_exc), [
' File "<console>", line 1\n',
' 1\n',
'IndentationError: unexpected indent\n'])

def test_sysexcepthook_crashing_doesnt_close_repl(self):
self.infunc.side_effect = ["1/0", "a = 123", "print(a)", EOFError('Finished')]
Expand Down Expand Up @@ -167,6 +266,11 @@ def test_cause_tb(self):
ValueError
""")
self.assertIn(expected, output)
self.assertIs(self.sysmod.last_type, ValueError)
self.assertIs(type(self.sysmod.last_value), ValueError)
self.assertIs(self.sysmod.last_traceback, self.sysmod.last_value.__traceback__)
self.assertIsNotNone(self.sysmod.last_traceback)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)

def test_context_tb(self):
self.infunc.side_effect = ["try: ham\nexcept: eggs\n",
Expand All @@ -185,6 +289,11 @@ def test_context_tb(self):
NameError: name 'eggs' is not defined
""")
self.assertIn(expected, output)
self.assertIs(self.sysmod.last_type, NameError)
self.assertIs(type(self.sysmod.last_value), NameError)
self.assertIs(self.sysmod.last_traceback, self.sysmod.last_value.__traceback__)
self.assertIsNotNone(self.sysmod.last_traceback)
self.assertIs(self.sysmod.last_exc, self.sysmod.last_value)


class TestInteractiveConsoleLocalExit(unittest.TestCase, MockSys):
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2024-07-31-20-43-21.gh-issue-122478.sCU2Le.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Remove internal frames from tracebacks shown in
:class:`code.InteractiveInterpreter` with non-default :func:`sys.excepthook`.
Save correct tracebacks in :attr:`sys.last_traceback` and update ``__traceback__`` attribute of :attr:`sys.last_value` and :attr:`sys.last_exc`.
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What do you mean by 'the correct' traceback?

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With removed frames.

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