The new REPL outputs different tracebeck when custom sys.excepthook is used

[serhiy-storchaka]

Bug report

If sys.systemhook is not sys.__systemhook__, the new REPL outputs the line in the code module in the traceback:

>>> xxx
Traceback (most recent call last):
 File "<python-input-0>", line 1, in <module>
 xxx
NameError: name 'xxx' is not defined
>>> import sys; sys.excepthook = lambda *args: sys.__excepthook__(*args)
>>> xxx
Traceback (most recent call last):
 File "/home/serhiy/py/cpython/Lib/code.py", line 91, in runcode
 exec(code, self.locals)
 ~~~~^^^^^^^^^^^^^^^^^^^
 File "<python-input-2>", line 1, in <module>
 xxx
NameError: name 'xxx' is not defined

Linked PRs

• gh-122478: Remove internal frames from tracebacks in REPL #122528
• [3.12] gh-122478: Remove internal frames from tracebacks in REPL (GH-122528) #122816
• [3.13] gh-122478: Remove internal frames from tracebacks in REPL (GH-122528) #122817
• [3.13] gh-122478: Remove internal frames from tracebacks in REPL (GH-122528) #123227

[serhiy-storchaka]

And for compile-time errors:

>>> ?
 File "<unknown>", line 1
 ?
 ^
SyntaxError: invalid syntax
>>> import sys; sys.excepthook = lambda *args: sys.__excepthook__(*args)
>>> ?
Traceback (most recent call last):
 File "/home/serhiy/py/cpython/Lib/_pyrepl/console.py", line 172, in runsource
 tree = ast.parse(source)
 File "/home/serhiy/py/cpython/Lib/ast.py", line 53, in parse
 return compile(source, filename, mode, flags,
 _feature_version=feature_version, optimize=optimize)
 File "<unknown>", line 1
 ?
 ^
SyntaxError: invalid syntax

[devdanzin]

Seems to be done on purpose in code.InteractiveInterpreter.showsyntaxerror:

cpython/Lib/code.py

Lines 126 to 132 in bd3d31f

	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)

I suppose this could be overridden in _pyrepl to always output with .write()?

[serhiy-storchaka]

sys.excepthook is of course called on purpose, but the traceback was not corrected for it. And sys.last_traceback was not always correct even with the default sys.excepthook.