Fix symbol table sub_table desync for non-simple annotation targets by youknowone · Pull Request #7300 · RustPython/RustPython · GitHub

Non-simple annotations (subscript/attribute/parenthesized targets like a[0]: expr) were scanned in the annotation scope during symbol table analysis, creating sub_tables for any comprehensions. But codegen only compiles simple name annotations into annotate, so those sub_tables were never consumed. This caused subsequent simple annotations' comprehension sub_tables to get the wrong index, resulting in "the symbol 'X' must be present in the symbol table" errors.

Fix: skip entering annotation scope for non-simple annotations since they are never compiled into annotate.

Summary by CodeRabbit

Refactor
- Adjusted how annotation scopes are treated so annotations are always handled as non-async.
- Improved annotation validation for assignment targets: retained detailed scanning for simple names while using safer validation for complex targets to avoid inconsistent internal annotation state.

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 8b61e74 and 8bd6e97.

📒 Files selected for processing (1)

crates/codegen/src/symboltable.rs

📝 Walkthrough

Walkthrough

This change narrows annotation scanning in the symbol table: annotation scopes are treated as non-async, and AnnAssign annotations are handled differently for simple names versus complex targets, validating complex annotations without creating separate annotation sub-tables. (48 words)

Changes

Cohort / File(s)	Summary
Symbol Table Annotation Handling crates/codegen/src/symboltable.rs	Short-circuit is_in_async_context to non-async when in_annotation is true. In AnnAssign, simple-name targets use scan_annotation(annotation); non-simple targets skip direct annotation scanning, temporarily set in_annotation = true, validate via scan_expression(annotation, Load), then restore state to avoid creating mismatched annotation sub-tables.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

Fix annotation scope, deadlock, MRO, and HEAPTYPE issues #7087: Related adjustments to symboltable annotation handling and async-context behavior.
handle type annotations in nested functions correctly #7072: Related changes around saving/restoring annotation_block and annotation-scope handling.

Poem

🐰 I hopped through scopes with careful feet,
Marked annotations tidy, neat,
Simple names sing their old refrain,
Complex ones get checked, then hop again,
A little rabbit cheers the table's feat!

🚥 Pre-merge checks | ✅ 3 ✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Fix symbol table sub_table desync for non-simple annotation targets' directly addresses the main problem described in the PR objectives: preventing sub_table creation for non-simple annotation targets to fix index desynchronization.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✏️ Tip: You can configure your own custom pre-merge checks in the settings.

✨ Finishing Touches 🧪 Generate unit tests (beta)

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

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

Comment @coderabbitai help to get the list of available commands and usage tips.

Code has been automatically formatted

The code in this PR has been formatted using:

cargo fmt --all
Please pull the latest changes before pushing again:

git pull origin fix-subtable

📦 Library Dependencies

The following Lib/ modules were modified. Here are their dependencies:

[x] lib: cpython/Lib/typing.py
[ ] test: cpython/Lib/test/test_typing.py (TODO: 4)
[x] test: cpython/Lib/test/test_type_aliases.py
[x] test: cpython/Lib/test/test_type_annotations.py
[x] test: cpython/Lib/test/test_type_params.py (TODO: 6)
[x] test: cpython/Lib/test/test_genericalias.py

dependencies:

typing

dependent tests: (17 tests)

typing: test_annotationlib test_builtin test_copy test_enum test_fractions test_funcattrs test_functools test_genericalias test_grammar test_inspect test_isinstance test_patma test_pydoc test_type_aliases test_type_params test_types test_typing

Legend:

[+] path exists in CPython
[x] up-to-date, [ ] outdated

Non-simple annotations (subscript/attribute/parenthesized targets like `a[0]: expr`) were scanned in the annotation scope during symbol table analysis, creating sub_tables for any comprehensions. But codegen only compiles simple name annotations into __annotate__, so those sub_tables were never consumed. This caused subsequent simple annotations' comprehension sub_tables to get the wrong index, resulting in "the symbol 'X' must be present in the symbol table" errors. Fix: skip entering annotation scope for non-simple annotations since they are never compiled into __annotate__.

Fix cspell "desynchronize" warning and validate yield/await/named/async comprehension expressions in non-simple annotations without creating annotation scopes.

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@crates/codegen/src/symboltable.rs`:
- Around line 1470-1484: The early-return in scan_expression when handling
non-simple annotation targets can bypass restoring the in_annotation flag;
update the branch in the function containing is_simple_name so that before
calling self.scan_expression(annotation, ExpressionContext::Load)? you set
was_in_annotation = self.in_annotation, set self.in_annotation = true, and
ensure self.in_annotation is restored to was_in_annotation even if
scan_expression returns an error (use a match/let res pattern or a
try/finally-style restore before propagating the error), mirroring the
restoration pattern used by scan_annotation; also add a regression test
exercising a non-simple annotated assignment with a forbidden expression (e.g.,
x[0]: (yield 1) = 1) to the test suite to verify the flag is always restored.

ℹ️ Review info

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 888e0ee and 8b61e74.

⛔ Files ignored due to path filters (1)

Lib/test/test_type_annotations.py is excluded by !Lib/**

📒 Files selected for processing (1)

crates/codegen/src/symboltable.rs

…ustPython#7300) * Fix symbol table sub_table desync for non-simple annotation targets Non-simple annotations (subscript/attribute/parenthesized targets like `a[0]: expr`) were scanned in the annotation scope during symbol table analysis, creating sub_tables for any comprehensions. But codegen only compiles simple name annotations into __annotate__, so those sub_tables were never consumed. This caused subsequent simple annotations' comprehension sub_tables to get the wrong index, resulting in "the symbol 'X' must be present in the symbol table" errors. Fix: skip entering annotation scope for non-simple annotations since they are never compiled into __annotate__. * Validate forbidden expressions in non-simple annotation targets Fix cspell "desynchronize" warning and validate yield/await/named/async comprehension expressions in non-simple annotations without creating annotation scopes. * Restore in_annotation flag before propagating error

youknowone added 2 commits March 2, 2026 11:07

Validate forbidden expressions in non-simple annotation targets

8b61e74

Fix cspell "desynchronize" warning and validate yield/await/named/async comprehension expressions in non-simple annotations without creating annotation scopes.

youknowone force-pushed the fix-subtable branch from 14204f6 to 8b61e74 Compare March 2, 2026 02:07

youknowone marked this pull request as ready for review March 2, 2026 03:37

coderabbitai Bot reviewed Mar 2, 2026

View reviewed changes

Comment thread crates/codegen/src/symboltable.rs

Restore in_annotation flag before propagating error

8bd6e97

youknowone merged commit baba1f9 into RustPython:main Mar 2, 2026
13 of 14 checks passed

youknowone deleted the fix-subtable branch March 2, 2026 07:47

This was referenced Mar 16, 2026

Consume nested scope tables in optimized-out asserts #7438

Merged

Fix sub_table ordering for nested inlined comprehensions (PEP 709) #7480

Merged

Fix symbol table sub_table desync for non-simple annotation targets by youknowone · Pull Request #7300 · RustPython/RustPython · GitHub

Uh oh!

Fix symbol table sub_table desync for non-simple annotation targets - #7300

Fix symbol table sub_table desync for non-simple annotation targets#7300
youknowone merged 3 commits into
RustPython:mainfrom
youknowone:fix-subtable

youknowone commented Mar 1, 2026 •
edited by coderabbitai Bot
Loading

Uh oh!

Uh oh!

coderabbitai Bot commented Mar 1, 2026 •
edited
Loading

Uh oh!

Uh oh!

github-actions Bot commented Mar 1, 2026

Uh oh!

github-actions Bot commented Mar 1, 2026 •
edited
Loading

Uh oh!

Uh oh!

coderabbitai Bot left a comment

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Fix symbol table sub_table desync for non-simple annotation targets by youknowone · Pull Request #7300 · RustPython/RustPython · GitHub

Uh oh!

Fix symbol table sub_table desync for non-simple annotation targets - #7300

Fix symbol table sub_table desync for non-simple annotation targets#7300youknowone merged 3 commits intoRustPython:mainRustPython/RustPython:mainfrom youknowone:fix-subtableyouknowone/RustPython:fix-subtableCopy head branch name to clipboard

Conversation

youknowone commented Mar 1, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary by CodeRabbit

Uh oh!

coderabbitai Bot commented Mar 1, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Walkthrough

Changes

Estimated code review effort

Possibly related PRs

Poem

Uh oh!

github-actions Bot commented Mar 1, 2026

Uh oh!

github-actions Bot commented Mar 1, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

📦 Library Dependencies

Uh oh!

coderabbitai Bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Fix symbol table sub_table desync for non-simple annotation targets#7300
youknowone merged 3 commits into
RustPython:mainfrom
youknowone:fix-subtable

youknowone commented Mar 1, 2026 •
edited by coderabbitai Bot
Loading

coderabbitai Bot commented Mar 1, 2026 •
edited
Loading

github-actions Bot commented Mar 1, 2026 •
edited
Loading