Fix RecursionError in infer_call_result()

[jacobtylerwalls]

Type of Changes

	Type
✓	🐛 Bug fix

Description

Closes pylint-dev/pylint#9139

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.78%. Comparing base (0ccc2e2) to head (5dfa9e2).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2432   +/-   ##
=======================================
  Coverage   92.78%   92.78%           
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  Files          94       94           
  Lines       11098    11102    +4     
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+ Hits        10297    10301    +4     
  Misses        801      801           

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linux	92.59% <100.00%> (+<0.01%)	⬆️
pypy	92.78% <100.00%> (+<0.01%)	⬆️
windows	92.68% <100.00%> (+<0.01%)	⬆️

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Files	Coverage Δ
astroid/bases.py	88.32% <100.00%> (+0.12%)	⬆️

[Pierre-Sassoulas]

I see nothing wrong here, but I would lie if I say I understand what was happening here :D would you mind explaining (very slowly) ?

[jacobtylerwalls]

Of course! I noticed that the recursion error reports in pylint seemed to have a line from infer_call_result() in common in the tracebacks, so I looked to see if there was an addressable issue there. I found that pytorch was doing something elaborate with __call__ that was causing astroid to get stuck in a loop, evaluating the result of a call to __call__.

I edited the test to show this more clearly. Inferring the result of A.__call__() requires... inferring the result of A(), which requires inferring the result of A.__call__(), ...

If you comment out the code change and run the test, you'll see the recursive calls in the pytest output:

astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):
astroid/bases.py:334: in infer_call_result
    for res in node.infer_call_result(caller, context):

The point of the patch is to notice that the two things being checked are the same class and bail out.

[jacobtylerwalls]

(The self and node are both Instances of A, and the ._proxied on each is the ClassDef for A they have in common.)

[Pierre-Sassoulas]

Thank you for explaining, make sense !

[Pierre-Sassoulas]

(Sorry forgot to approve)