python / python/cpython

REPLs don't handle `SystemError` from the compiler

Ouverte
#150,732 0 commentaires 0 réactions 1 personne assignée Voir sur GitHub

@johnslavik y travaille déjà.

Depuis le 1/6/2026.

3.14 3.15 3.16 stdlib topic-repl type-bug
Langage dominant
Python
Étoiles
77.2k
Forks
35.9k
Métriques de merge des PR
Métriques de PR en attente

Description

Bug report

Bug description:

During investigating #150700 I found that running the snippet class X: [(lambda: __class__)() for () in ()] causes the following bugs to appear:

  1. The REPL leaks _IncompleteInputError, which aborts writing the user input to history
  2. The user input isn't shown; Traceback is shown immediately after the prompt string >>>
❯ ./python.exe
Python 3.16.0a0 (heads/gh-143535-singledispatchmethod-dispatches-on-first-argument:fad06746051, M) [Clang 17.0.0 (clang-1700.6.3.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> Traceback (most recent call last):r () in ()]
  File "/Users/bartosz.slawecki/Python/cpython/Lib/codeop.py", line 64, in _maybe_compile
    compiler(source, filename, symbol, flags=flags)
    ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/bartosz.slawecki/Python/cpython/Lib/codeop.py", line 117, in __call__
    codeob = compile(source, filename, symbol, flags, True)
  File "<stdin>", line 1
    class X: [(lambda: __class__)() for () in ()]
                                                ^
_IncompleteInputError: incomplete input

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/bartosz.slawecki/Python/cpython/Lib/_pyrepl/readline.py", line 406, in multiline_input
    return reader.readline()
           ~~~~~~~~~~~~~~~^^
  File "/Users/bartosz.slawecki/Python/cpython/Lib/_pyrepl/reader.py", line 1021, in readline
    self.handle1()
    ~~~~~~~~~~~~^^
  File "/Users/bartosz.slawecki/Python/cpython/Lib/_pyrepl/reader.py", line 1004, in handle1
    self.do_cmd(cmd)
    ~~~~~~~~~~~^^^^^
  File "/Users/bartosz.slawecki/Python/cpython/Lib/_pyrepl/reader.py", line 924, in do_cmd
    command.do()
    ~~~~~~~~~~^^
  File "/Users/bartosz.slawecki/Python/cpython/Lib/_pyrepl/readline.py", line 297, in do
    r.more_lines is not None and r.more_lines(text)
                                 ~~~~~~~~~~~~^^^^^^
  File "/Users/bartosz.slawecki/Python/cpython/Lib/_pyrepl/simple_interact.py", line 85, in _more_lines
    code = console.compile(src, "<stdin>", "single")
  File "/Users/bartosz.slawecki/Python/cpython/Lib/codeop.py", line 154, in __call__
    return _maybe_compile(self.compiler, source, filename, symbol, flags=self.compiler.flags)
  File "/Users/bartosz.slawecki/Python/cpython/Lib/codeop.py", line 67, in _maybe_compile
    compiler(source + "\n", filename, symbol, flags=flags)
    ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/bartosz.slawecki/Python/cpython/Lib/codeop.py", line 117, in __call__
    codeob = compile(source, filename, symbol, flags, True)
SystemError: compiler_lookup_arg(name='__class__') with reftype=5 failed in X; freevars of code <lambda>: ('__class__',)

I believe SystemError should be handled.

CPython versions tested on:

3.14, 3.15, 3.16, CPython main branch

Operating systems tested on:

macOS

Linked PRs
  • gh-151480

Guide de contribution

Ouvrir le guide de contribution

Par où commencer

  1. Lisez l'issue en entier, puis le guide de contribution du projet.
  2. Signalez en commentaire que vous la prenez — cela évite que deux personnes fassent le même travail.
  3. Forkez le dépôt et travaillez sur une branche.
  4. Ouvrez une pull request qui référence le numéro de l'issue.

Évaluation

Cette issue n'a pas encore été évaluée.

Recevez les nouvelles issues par e-mail

Un résumé court des issues GitHub adaptées aux débutants.