For example,./python -m pydoc test.test_enum takes 32 seconds. It is 20 seconds in 3.12, 15 seconds in 3.11 and only 1.6 seconds in 3.10. Well, perhapstest.test_enum was grown, but the main culprit isbpo-35113. And further changes likegh-106727 only added to it.

For every class without a docstringpydoc tries to find its comments by callinginspect.getcomments() which callsinspect.findsource() which reads and parses the module source, then traverse it and find classes with the specific qualname. For large modules with many classes it has quadratic complexity.

I tried to optimize the AST traversing code, and get 18 seconds on main. It still has quadratic complexity. Further optimization will require introducing a cache and finding positions of all classes in one pass.

But it all would be much simpler and faster if simply save the value ofco_firstlineno of the code object executed during class creation in the file dict (as__firstlineno__ for example).

Linked PRs

• gh-118465: Optimize inspect.findsource() for classes #118471
• gh-118465: Add __firstlineno__ attribute to class #118475