When I try to run IPython’s tests on NixOS 25.05, these tests fail:

• tests/test_interactiveshell.py::ExitCodeChecks::test_exit_code_signal
• tests/test_interactiveshell.py::TestSystemRaw::test_exit_code_signal
• tests/test_interactiveshell.py::TestSystemPipedExitCode::test_exit_code_signal

EDIT: It turns out that those failures happen only if you store IPython’s source code in a directory that has at least one space in its path.

Steps to reproduce

1. Make sure that you have a copy of IPython’s Git repository on your system. Make sure that the path to your copy of IPython’s Git repository contains at least one space.

2. Open a terminal.

3. Make sure that you have the python command. If you use the Nix package manager, then you can make sure that you have the exact same version of Python that I used to reproduce this bug by doing the following:

   1. Create a file named shell-for-working-on-ipython.nix that contains the following Nix expression:

      # This file is dedicated to the public domain using 🅭🄍1.0:
      # <https://creativecommons.org/publicdomain/zero/1.0>.
      let
        nixpkgsCommit = "09eb77e94fa25202af8f3e81ddc7353d9970ac1b";
        nixpkgsDirectory = builtins.fetchTarball {
          url = "https://github.com/NixOS/nixpkgs/archive/${nixpkgsCommit}.tar.gz";
          sha256 = "02hdh4r0cc5h78cmymndb8clfhkn6phbrkrv6s8kvyfspqwzj84r";
        };
        pkgs = import nixpkgsDirectory { };
      in
      pkgs.mkShellNoCC {
        name = "shell-for-working-on-ipython";
        packages = [ pkgs.python314 ];
      }

   2. Activate that Nix shell by running the following command:

      nix-shell <path to shell-for-working-on-ipython.nix>

4. Create a new virtual environment by running this command:

   python -m venv <path to where you want the venv to be created>

5. Activate the virtual environment that you just created. (See this section of the Python documentation).

6. (Recommended) Update pip by running this command:

   python -m pip install --upgrade pip

7. Change directory to the root of your local copy of IPython’s Git repository by doing one of the following:

   • If your terminal is using the Windows Command Shell, then run this command:

     CD /D <path to repo>

   • Otherwise, run this command:

     cd <path to repo>

8. (Optional) Switch to a Git commit that is known to have this issue by running this command:

   git switch --detach f63b2acb992e0e88619f4486bc67620f9f50fe50

9. Install a development version of IPython by running this command:

   pip install -e '.[test]'

10. Run IPython’s tests by running this command:

    pytest

Results

===================================================== test session starts ======================================================
platform linux -- Python 3.14.0, pytest-9.0.2, pluggy-1.6.0
rootdir: /home/jayman/Documents/Home/VC/Git/Not mine/ipython/repo
configfile: pyproject.toml
plugins: asyncio-1.3.0
asyncio: mode=Mode.STRICT, debug=False, asyncio_default_fixture_loop_scope=None, asyncio_default_test_loop_scope=function
collected 1728 items / 2 skipped

IPython/core/completer.py ss                                                                                             [  0%]
IPython/core/debugger.py s                                                                                               [  0%]
IPython/core/display.py ..                                                                                               [  0%]
IPython/core/display_functions.py .                                                                                      [  0%]
IPython/core/formatters.py .                                                                                             [  0%]
IPython/core/history.py .                                                                                                [  0%]
IPython/core/interactiveshell.py .s.s                                                                                    [  0%]
IPython/core/magics/ast_mod.py s                                                                                         [  0%]
IPython/core/magics/auto.py s                                                                                            [  0%]
IPython/core/magics/basic.py ss                                                                                          [  0%]
IPython/core/magics/code.py s.                                                                                           [  1%]
IPython/core/magics/config.py .                                                                                          [  1%]
IPython/core/magics/execution.py ssssss                                                                                  [  1%]
IPython/core/magics/history.py s                                                                                         [  1%]
IPython/core/magics/namespace.py s..sss                                                                                  [  1%]
IPython/core/magics/osm.py ssss                                                                                          [  2%]
IPython/core/magics/pylab.py s                                                                                           [  2%]
IPython/core/magics/script.py .                                                                                          [  2%]
IPython/core/oinspect.py s                                                                                               [  2%]
IPython/extensions/autoreload.py s                                                                                       [  2%]
IPython/extensions/storemagic.py s                                                                                       [  2%]
IPython/extensions/tests/test_deduperreload.py ......................................................................... [  6%]
.                                                                                                                        [  6%]
IPython/lib/display.py s                                                                                                 [  6%]
IPython/terminal/magics.py s                                                                                             [  6%]
IPython/terminal/shortcuts/auto_suggest.py .                                                                             [  6%]
IPython/testing/plugin/dtexample.py .......                                                                              [  7%]
IPython/testing/plugin/simple.py ..                                                                                      [  7%]
IPython/testing/plugin/test_combo.txt .                                                                                  [  7%]
IPython/testing/plugin/test_example.txt ..                                                                               [  7%]
IPython/testing/plugin/test_exampleip.txt .                                                                              [  7%]
IPython/testing/plugin/test_ipdoctest.py .....                                                                           [  7%]
IPython/testing/plugin/test_refs.py ....                                                                                 [  8%]
IPython/testing/tools.py ..                                                                                              [  8%]
IPython/utils/contexts.py .                                                                                              [  8%]
IPython/utils/frame.py .                                                                                                 [  8%]
IPython/utils/ipstruct.py ...........                                                                                    [  8%]
IPython/utils/path.py .                                                                                                  [  8%]
IPython/utils/strdispatch.py .                                                                                           [  9%]
IPython/utils/sysinfo.py .                                                                                               [  9%]
IPython/utils/text.py .......                                                                                            [  9%]
tests/test_alias.py ....                                                                                                 [  9%]
tests/test_application.py ...                                                                                            [  9%]
tests/test_async_helpers.py .ssss......                                                                                  [ 10%]
tests/test_autocall.py ..                                                                                                [ 10%]
tests/test_backgroundjobs.py ....                                                                                        [ 10%]
tests/test_capture.py ........................                                                                           [ 12%]
tests/test_clipboard.py .                                                                                                [ 12%]
tests/test_compilerop.py ......                                                                                          [ 12%]
tests/test_completer.py ...........................................s.................................................... [ 18%]
.s...................................................................................................................... [ 25%]
........................xxx...................................                                                           [ 28%]
tests/test_completerlib.py ............                                                                                  [ 29%]
tests/test_cve.py .                                                                                                      [ 29%]
tests/test_debug_magic.py .                                                                                              [ 29%]
tests/test_debugger.py ..........sss...                                                                                  [ 30%]
tests/test_decorators.py .ss..s.ss..                                                                                     [ 31%]
tests/test_decorators_2.py .                                                                                             [ 31%]
tests/test_deepreload.py ...                                                                                             [ 31%]
tests/test_dir2.py ....                                                                                                  [ 31%]
tests/test_display.py ..............ss.sssss.ssss.                                                                       [ 33%]
tests/test_display_2.py ........ssss..............                                                                       [ 34%]
tests/test_displayhook.py .......                                                                                        [ 35%]
tests/test_editorhooks.py .                                                                                              [ 35%]
tests/test_embed.py ..                                                                                                   [ 35%]
tests/test_events.py .....                                                                                               [ 35%]
tests/test_exceptiongroup_tb.py sssssssss                                                                                [ 36%]
tests/test_extension.py ...                                                                                              [ 36%]
tests/test_formatters.py ................................                                                                [ 38%]
tests/test_guarded_eval.py .ss.ssss..................................................................................... [ 43%]
........................................................................................................................ [ 50%]
.............................................................................s..                                         [ 55%]
tests/test_handlers.py ....................                                                                              [ 56%]
tests/test_help.py ......s                                                                                               [ 56%]
tests/test_history.py ......................                                                                             [ 57%]
tests/test_hooks.py ...                                                                                                  [ 58%]
tests/test_imports.py ...                                                                                                [ 58%]
tests/test_importstring.py ...                                                                                           [ 58%]
tests/test_inputtransformer2.py .........................................                                                [ 60%]
tests/test_inputtransformer2_line.py .........                                                                           [ 61%]
tests/test_interactiveshell.py .............................................Fs....Fs.....Fs...........................s  [ 66%]
tests/test_interactivshell.py .........                                                                                  [ 66%]
tests/test_io.py ...                                                                                                     [ 67%]
tests/test_iplib.py .......                                                                                              [ 67%]
tests/test_ipunittest.py .....                                                                                           [ 67%]
tests/test_latextools.py ..sssssss...s.                                                                                  [ 68%]
tests/test_logger.py ..                                                                                                  [ 68%]
tests/test_magic.py ......................s..............................s..............sss..................

=========================================================== FAILURES ===========================================================
_____________________________________________ ExitCodeChecks.test_exit_code_signal _____________________________________________

self = <tests.test_interactiveshell.ExitCodeChecks testMethod=test_exit_code_signal>

    @skipif(not hasattr(signal, "SIGALRM"))
    def test_exit_code_signal(self):
        self.mktmp(
            "import signal, time\n"
            "signal.setitimer(signal.ITIMER_REAL, 0.1)\n"
            "time.sleep(1)\n"
        )
        self.system("%s %s" % (sys.executable, self.fname))
>       self.assertEqual(ip.user_ns["_exit_code"], -signal.SIGALRM)
E       AssertionError: 127 != -14

tests/test_interactiveshell.py:661: AssertionError
----------------------------------------------------- Captured stderr call -----------------------------------------------------
/nix/store/nn27l879np49xvx6l1a8nqnqlp9apd8n-bash-interactive-5.2p37/bin/bash: line 1: /home/jayman/Documents/Home/VC/Git/Not: No such file or directory
_____________________________________________ TestSystemRaw.test_exit_code_signal ______________________________________________

self = <tests.test_interactiveshell.TestSystemRaw testMethod=test_exit_code_signal>

    @skipif(not hasattr(signal, "SIGALRM"))
    def test_exit_code_signal(self):
        self.mktmp(
            "import signal, time\n"
            "signal.setitimer(signal.ITIMER_REAL, 0.1)\n"
            "time.sleep(1)\n"
        )
        self.system("%s %s" % (sys.executable, self.fname))
>       self.assertEqual(ip.user_ns["_exit_code"], -signal.SIGALRM)
E       AssertionError: 127 != -14

tests/test_interactiveshell.py:661: AssertionError
----------------------------------------------------- Captured stderr call -----------------------------------------------------
/nix/store/nn27l879np49xvx6l1a8nqnqlp9apd8n-bash-interactive-5.2p37/bin/bash: line 1: /home/jayman/Documents/Home/VC/Git/Not: No such file or directory
________________________________________ TestSystemPipedExitCode.test_exit_code_signal _________________________________________

self = <tests.test_interactiveshell.TestSystemPipedExitCode testMethod=test_exit_code_signal>

    @skip_win32
    def test_exit_code_signal(self):
>       ExitCodeChecks.test_exit_code_signal(self)

tests/test_interactiveshell.py:733:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
tests/test_interactiveshell.py:661: in test_exit_code_signal
    self.assertEqual(ip.user_ns["_exit_code"], -signal.SIGALRM)
E   AssertionError: 127 != -14
----------------------------------------------------- Captured stdout call -----------------------------------------------------
/nix/store/nn27l879np49xvx6l1a8nqnqlp9apd8n-bash-interactive-5.2p37/bin/bash: line 1: /home/jayman/Documents/Home/VC/Git/Not: No such file or directory
======================================================= warnings summary =======================================================
tests/test_async_helpers.py::AsyncTest::test_in_func_no_error
  <>:8: SyntaxWarning: 'return' in a 'finally' block

tests/test_async_helpers.py::AsyncTest::test_in_func_no_error
tests/test_async_helpers.py::AsyncTest::test_in_func_no_error
  <ipython-input-1-a475a201f42b>:8: SyntaxWarning: 'return' in a 'finally' block
    return

tests/test_async_helpers.py::AsyncTest::test_top_level_return_error
  <>:6: SyntaxWarning: 'return' in a 'finally' block

tests/test_async_helpers.py::AsyncTest::test_top_level_return_error
tests/test_async_helpers.py::AsyncTest::test_top_level_return_error
  <ipython-input-1-714c4c819d0d>:6: SyntaxWarning: 'return' in a 'finally' block
    return

tests/test_debug_magic.py: 1 warning
tests/test_debugger.py: 8 warnings
tests/test_embed.py: 1 warning
tests/test_interactiveshell.py: 3 warnings
  /nix/store/sddj4ifk8jdpqi1vzzz6cl7bb0cshskx-python3-3.14.0/lib/python3.14/pty.py:66: DeprecationWarning: This process (pid=554813) is multi-threaded, use of forkpty() may lead to deadlocks in the child.
    pid, fd = os.forkpty()

tests/test_debugger.py: 9 warnings
tests/test_magic.py: 2 warnings
  /home/jayman/Documents/Home/VC/Git/Not mine/ipython/repo/IPython/core/debugger.py:617: DeprecationWarning: The frame locals reference is no longer cached. Use 'curframe.f_locals' instead.
    return self.curframe_locals

tests/test_debugger.py::tests.test_debugger.test_ipdb_magics
  /home/jayman/Documents/Home/VC/Git/Not mine/ipython/repo/IPython/core/debugger.py:958: DeprecationWarning: The frame locals reference is no longer cached. Use 'curframe.f_locals' instead.
    ("Locals", self.curframe_locals),

tests/test_debugger.py::tests.test_debugger.test_ipdb_magics
  /home/jayman/Documents/Home/VC/Git/Not mine/ipython/repo/IPython/core/debugger.py:969: DeprecationWarning: The frame locals reference is no longer cached. Use 'curframe.f_locals' instead.
    ("Locals", self.curframe_locals),

tests/test_debugger.py::tests.test_debugger.test_ipdb_magics
  /home/jayman/Documents/Home/VC/Git/Not mine/ipython/repo/IPython/core/debugger.py:992: DeprecationWarning: The frame locals reference is no longer cached. Use 'curframe.f_locals' instead.
    ("Locals", self.curframe_locals),

tests/test_inputtransformer2.py::test_check_make_token_by_line_never_ends_empty
  /home/jayman/Documents/Home/VC/Git/Not mine/ipython/repo/tests/test_inputtransformer2.py:188: UserWarning: `make_tokens_by_line` received a list of lines which do not have lineending markers ('\n', '\r', '\r\n', '\x0b', '\x0c'), behavior will be unspecified
    assert make_tokens_by_line(c + k)[-1] != []

tests/test_interactiveshell.py::test_run_cell_async
  /nix/store/sddj4ifk8jdpqi1vzzz6cl7bb0cshskx-python3-3.14.0/lib/python3.14/asyncio/events.py:94: DeprecationWarning: `run_cell_async` will not call `transform_cell` automatically in the future. Please pass the result to `transformed_cell` argument and any exception that happen during thetransform in `preprocessing_exc_tuple` in IPython 7.17 and above.
    self._context.run(self._callback, *self._args)

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
===================================================== slowest 10 durations =====================================================
3.95s call     tests/test_debugger.py::test_ignore_module_all_commands
2.15s call     IPython/extensions/tests/test_deduperreload.py::DecoratorPatchingSuite::test_function_decorators
2.00s call     tests/test_magic.py::test_timeit_raise_on_interrupt
1.72s call     tests/test_debugger.py::test_xmode_skip
1.53s call     tests/test_embed.py::test_nest_embed
1.33s call     tests/test_debug_magic.py::test_debug_magic_passes_through_generators
1.26s call     tests/test_debugger.py::test_where_erase_value
1.12s call     IPython/extensions/tests/test_deduperreload.py::TestAutoreloadEnum::test_reload_enums
1.11s call     IPython/extensions/tests/test_deduperreload.py::DecoratorPatchingSuite::test_modify_property
1.10s call     tests/test_debugger.py::test_ignore_module_basic_functionality
=================================================== short test summary info ====================================================
FAILED tests/test_interactiveshell.py::ExitCodeChecks::test_exit_code_signal - AssertionError: 127 != -14
FAILED tests/test_interactiveshell.py::TestSystemRaw::test_exit_code_signal - AssertionError: 127 != -14
FAILED tests/test_interactiveshell.py::TestSystemPipedExitCode::test_exit_code_signal - AssertionError: 127 != -14
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! KeyboardInterrupt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
/nix/store/sddj4ifk8jdpqi1vzzz6cl7bb0cshskx-python3-3.14.0/lib/python3.14/threading.py:1132: KeyboardInterrupt
(to show a full traceback on KeyboardInterrupt use --full-trace)
======================== 3 failed, 1178 passed, 96 skipped, 3 xfailed, 35 warnings in 82.23s (0:01:22) =========================