Bug report

Context: this issue came out of a discussion in #python on the Libera.chat IRC network, where a user wanted to peek intoimportlib._bootstrap withpdb while chasing a bug.

pdb is capable of stepping into function calls into frozen modules, but thelist command cannot locate the source code necessary to display the source being stepped through.

# repro.pyimportimportlib._bootstrap# some function call that we want to step into with pdbimportlib._bootstrap._resolve_name("os",".",1)

$ python3 -m pdb repro.py> /home/snoopjedi/repro.py(2)<module>()-> import importlib._bootstrap(Pdb) n> /home/snoopjedi/repro.py(5)<module>()-> importlib._bootstrap._resolve_name("os", ".", 1)(Pdb) s--Call--> <frozen importlib._bootstrap>(883)_resolve_name()(Pdb) l[EOF]

Note that executingsource importlib._bootstrap from the frame that calls into this moduledoes successfully locate the source, but this isn't very useful to a user ofpdb.

I believe that bringing the frame'sco_filename into agreement with the module's__file__ would fix this issue without changes topdb (see#89815), but thought it would be good to track the issue withpdb in a separate ticket since that fix is more nuanced and I think I have an interim patch for the debugger.

Your environment

• CPython versions tested on: 3.9.4, 3.11.0b3
• Operating system and architecture: Ubuntu 20.04, x86_64

Linked PRs

• gh-93696: Fixed the breakpoint display error for frozen modules #132862