doc handing in the right way by youknowone · Pull Request #6390 · RustPython/RustPython

youknowone

Walkthrough

Class codegen no longer emits a __doc__ entry when no docstring is provided; the load_docstring helper was removed. PyType construction now always creates member descriptors for __slots__ and prefers the type's own dict for __doc__ resolution, setting __doc__ in the type dict when absent.

Changes

Cohort / File(s)	Summary
Class compilation / docstring `crates/codegen/src/compile.rs`	Removed `fn load_docstring(&mut self, doc_str: Option<String>)`; emit `__doc__` only when `Some(doc)` is present (omit write when no docstring)
Type initialization & lookup `crates/vm/src/builtins/type.rs`	Always create and assign `PyMemberDescriptor` entries for `__slots__` members (overriding inherited attrs); set `__doc__` in the type dict if absent; change `__doc__` read to use the type's own dict (`get_direct_attr`) and use descriptor `__get__` when present
Test update `extra_tests/snippets/syntax_class.py`	Change assertion from `A.__doc__ == None` to `A.__doc__ is None` (identity check, clearer failure message)

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Pay attention to:
- crates/vm/src/builtins/type.rs — verify overriding semantics for slot descriptors and any unintended shadowing of inherited attributes.
- crates/codegen/src/compile.rs — ensure bytecode emitted when omitting __doc__ matches VM expectations.
- Integration between codegen and VM __doc__ behavior (absent vs explicit None in type dict).

Possibly related PRs

type.__dict__ #5957 — Related edits to vm/src/builtins/type.rs affecting type attribute insertion and slot handling.
Fix __dict__ getset type #6010 — Overlapping changes around slot-based descriptors and type initialization behavior.
Fix PyFunction doc behavior #5827 — Prior adjustments to __doc__ handling and descriptor/lookup semantics.

Poem

🐇 I tuck my docstrings neat and light,
Only store them when they’re right.
Slots wear badges, plainly shown,
Own-dict truths are safely known.
Hop, compile — the garden's bright!

Pre-merge checks and finishing touches

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%.	You can run `@coderabbitai generate docstrings` to improve docstring coverage.
Title check	❓ Inconclusive	The title contains a typo ('handing' instead of 'handling') and is vague about the specific improvements made to doc handling across the codebase.	Correct the typo and clarify the title to better describe the changes, such as 'Fix doc handling in class compilation and type initialization' or 'Make doc handling conditional and align with CPython behavior'.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

✨ Finishing touches

📝 Generate docstrings

🧪 Generate unit tests (beta)

Create PR with unit tests
Post copyable unit tests in a comment

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