`test_repl.test_toplevel_contextvars_async` fails under Fish in a VS Code terminal

[brettcannon]

Bug report

Bug description:

This is on VS Code insiders on Windows with a checkout in WSL.

➲ ./python -m test test_repl
Using random seed: 506736770
0:00:00 load avg: 0.01 Run 1 test sequentially in a single process
0:00:00 load avg: 0.01 [1/1] test_repl
test test_repl failed -- Traceback (most recent call last):
 File "/home/brett/Repositories/python/cpython/Lib/test/test_repl.py", line 339, in test_toplevel_contextvars_async
 self.assertIn(expected, output, expected)
 ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 'toplevel contextvar test: ok' not found in 'asyncio REPL 3.15.0a0 (heads/main-dirty:d7dbde89588, Aug 8 2025, 14:49:47) [Clang 14.0.6 ] on linux\nUse "await" directly instead of "asyncio.run()".\nType "help", "copyright", "credits" or "license" for more information.\nException in thread Interactive thread:\nexiting asyncio REPL...\nTraceback (most recent call last):\nTraceback (most recent call last):\n File "/home/brett/Repositories/python/cpython/Lib/runpy.py", line 198, in _run_module_as_main\n return _run_code(code, main_globals, None,\n "__main__", mod_spec)\n File "/home/brett/Repositories/python/cpython/Lib/threading.py", line 1074, in _bootstrap_inner\n self._context.run(self.run)\n ~~~~~~~~~~~~~~~~~^^^^^^^^^^\n File "/home/brett/Repositories/python/cpython/Lib/asyncio/__main__.py", line 105, in run\n exec(startup_code, console.locals)\n ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n File "/home/brett/.vscode-server-insiders/data/User/workspaceStorage/0abd4bd2132dfcbfde5adbe8d7792ee2/ms-python.python/pythonrc.py", line 5, in <module>\n import readline\nModuleNotFoundError: No module named \'readline\'\n File "/home/brett/Repositories/python/cpython/Lib/runpy.py", line 88, in _run_code\n exec(code, run_globals)\n ~~~~^^^^^^^^^^^^^^^^^^^\n File "/home/brett/Repositories/python/cpython/Lib/asyncio/__main__.py", line 245, in <module>\n sys.exit(return_code)\n ~~~~~~~~^^^^^^^^^^^^^\nSystemExit: 0\n>>> >>> >>> ... File "<stdin>", line 2\n await set_var()\n ^^^^^\nSyntaxError: invalid syntax\n>>> toplevel contextvar test: failed\n>>> \n' : toplevel contextvar test: ok

0:00:00 load avg: 0.17 [1/1/1] test_repl failed (1 failure)

== Tests result: FAILURE ==

1 test failed:
 test_repl

Total duration: 846 ms
Total tests: run=13 failures=1
Total test files: run=1/1 failed=1
Result: FAILURE

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

[johnslavik]

I wrote that test -- will take a look at it.

[johnslavik]

Oh, it's in the traceback.

AssertionError: 'toplevel contextvar test: ok' not found in s

where s is:

asyncio REPL 3.15.0a0 (heads/main-dirty:d7dbde89588, Aug 8 2025, 14:49:47) [Clang 14.0.6 ] on linux
Use "await" directly instead of "asyncio.run()".
Type "help", "copyright", "credits" or "license" for more information.
Exception in thread Interactive thread:
exiting asyncio REPL...
Traceback (most recent call last):
Traceback (most recent call last):
 File "/home/brett/Repositories/python/cpython/Lib/runpy.py", line 198, in _run_module_as_main
 return _run_code(code, main_globals, None,
 "__main__", mod_spec)
 File "/home/brett/Repositories/python/cpython/Lib/threading.py", line 1074, in _bootstrap_inner
 self._context.run(self.run)
 ~~~~~~~~~~~~~~~~~^^^^^^^^^^
 File "/home/brett/Repositories/python/cpython/Lib/asyncio/__main__.py", line 105, in run
 exec(startup_code, console.locals)
 ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/home/brett/.vscode-server-insiders/data/User/workspaceStorage/0abd4bd2132dfcbfde5adbe8d7792ee2/ms-python.python/pythonrc.py", line 5, in <module>
 import readline
ModuleNotFoundError: No module named 'readline'
 File "/home/brett/Repositories/python/cpython/Lib/runpy.py", line 88, in _run_code
 exec(code, run_globals)
 ~~~~^^^^^^^^^^^^^^^^^^^
 File "/home/brett/Repositories/python/cpython/Lib/asyncio/__main__.py", line 245, in <module>
 sys.exit(return_code)
 ~~~~~~~~^^^^^^^^^^^^^
SystemExit: 0
>>> >>> >>> ... File "<stdin>", line 2
 await set_var()
 ^^^^^
SyntaxError: invalid syntax
>>> toplevel contextvar test: failed
>>> 

The asyncio REPL tries to import readline in a startup file and exits as part of #140287 that I've reported today independently, and then it spawns a regular REPL because the interpreter was run with the -i flag.

Wow, what an interesting coincidence.

The easiest workaround is to have readline available or remove it from your PYTHONSTARTUP.
The fundamental question is why do we launch 2 REPLs in this test... (filed #140298 to fix)

[johnslavik]

@brettcannon This is just an instance of #140287. The asyncio REPL can work without readline, but you're trying to import readline in your startup file (/home/brett/.vscode-server-insiders/data/User/workspaceStorage/0abd4bd2132dfcbfde5adbe8d7792ee2/ms-python.python/pythonrc.py), it's unavailable, and the asyncio REPL doesn't handle PYTHONSTARTUP failures properly.

[johnslavik]

@ZeroIntensity (mentorship): Should we close this as duplicate or wait until the root issue is resolved and then close this afterwards?

[ZeroIntensity]

This doesn't look like an exact copy of #140287, so let's keep this open for now.