Inconsistent current line indication if the script is edited after entering `pdb`

[tanloong]

Bug report

Bug description:

1. create a for-loop.py

for i in range(10):
    breakpoint()
    print(i)

2. run python for-loop.py, entering the pdb interface

3. insert a line to for-loop.py after breakpoint()

for i in range(10):
    breakpoint()
    print("This is an inserted line.")
    print(i)

4. run c in pdb and the inserted line will be shown as current line indicated by ->, but the actual current line to be executed is print(i).

5. run c again. The print(i), instead of the inserted line, will be executed.

CPython versions tested on:

3.12

Operating systems tested on:

Linux

[gaogaotiantian]

See #111051. There's no perfect solution for this but we should warn user. The PR #111052 has been sitting there for a while but I have not had the chance to grab a core dev for it :)

[tanloong]

Thanks for replying! I will keep this repeated issue open to hopefully attract some core dev's attention to the PR.