No required version of typing_extensions is causing ImportError: cannot import name 'TypeAliasType' from 'typing_extensions'

[r00ta]

There are no version requirements on typing_extensions

ipython/pyproject.toml

Line 35 in b9c597d

"typing_extensions; python_version<'3.12'",

but actually you are importing

from typing_extensions import TypeAliasType

here

ipython/IPython/core/guarded_eval.py

Line 40 in b9c597d

from typing_extensions import TypeAliasType

and TypeAliasType has been added only in 4.6 python/typing_extensions@09c1ed4.

This means that if a system has already typing_extensions at version 4.4.0 (for example, on Ubuntu Jammy the deb package python3-typing-extensions is at version 4.4.0) pip will assume that 4.4.0 is ok, but you would end up with

Traceback (most recent call last):
  File "/work/maas/bin/py", line 5, in <module>
    from IPython import start_ipython
  File "/work/maas/.ve/lib/python3.10/site-packages/IPython/__init__.py", line 55, in <module>
    from .terminal.embed import embed
  File "/work/maas/.ve/lib/python3.10/site-packages/IPython/terminal/embed.py", line 16, in <module>
    from IPython.terminal.interactiveshell import TerminalInteractiveShell
  File "/work/maas/.ve/lib/python3.10/site-packages/IPython/terminal/interactiveshell.py", line 48, in <module>
    from .debugger import TerminalPdb, Pdb
  File "/work/maas/.ve/lib/python3.10/site-packages/IPython/terminal/debugger.py", line 6, in <module>
    from IPython.core.completer import IPCompleter
  File "/work/maas/.ve/lib/python3.10/site-packages/IPython/core/completer.py", line 219, in <module>
    from IPython.core.guarded_eval import guarded_eval, EvaluationContext
  File "/work/maas/.ve/lib/python3.10/site-packages/IPython/core/guarded_eval.py", line 40, in <module>
    from typing_extensions import TypeAliasType
ImportError: cannot import name 'TypeAliasType' from 'typing_extensions' (/usr/lib/python3/dist-packages/typing_extensions.py)

Tested on

Distributor ID:	Ubuntu
Description:	Ubuntu 22.04.3 LTS
Release:	22.04
Codename:	jammy

[krassowski]

Thanks! I opened #14381.