A RetroSearch Logo

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Search Query:

Showing content from https://github.com/python/cpython/issues/101673 below:

pdb loses local variable change after command longlist · Issue #101673 · python/cpython · GitHub

Bug report

In pdb, ll will clear the local variable change.

def main():
    a = 1
    breakpoint()
    print(a)

main()
-> print(a)
(Pdb) p a
1
(Pdb) !a = 2
(Pdb) p a
2
(Pdb) ll
  1     def main():
  2         a = 1
  3         breakpoint()
  4  ->     print(a)
(Pdb) p a
1
(Pdb) s
1
--Return--

As you can tell, a was changed through !a = 2 but it was reverted after ll. print(a) also prints the unmodified value. Without ll, everything works fine.

The reason lies in getsourcelines in pdb.py. In that function, it tried to access obj.f_locals, which will refresh the dict with PyFrame_FastToLocalsWithError as it's a property now.

if inspect.isframe(obj) and obj.f_globals is obj.f_locals:

As a result, the local variable changes will be erased.

The original reason to check if obj.f_globals is obj.f_locals is to check whether obj is an module frame. Now that it has side effects to pdb, we can do the check with:

if inspect.isframe(obj) and obj.f_code.co_name == "<module>":

It might not be the most delicate way, but I can't think of a situation where this won't work.

I did this change locally and I have confirmed:

  1. ./python -m test -j3 passed
  2. The original bug is fixed
  3. ll still prints the full file for module frame

I'll make a PR soon and please let me know if there are any concerns about the fix.

Your environment Linked PRs

arhadthedev, xpf629629, TravisCao, zyckk4, Harry-Jing and 5 more


RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4