[VedantMadane]

Summary

Fixes a SIM117 false negative when nested async with statements sit under a sync with parent (and the inverse).

Previously, SIM117 skipped any with whose parent was itself a single-statement with, so that nested cases were fixed top-to-bottom. That skip was unconditional, so a sync parent caused nested async bodies to be ignored even though sync/async contexts cannot be merged:

with contextlib.nullcontext() as ctx:
    async with mycontext() as actx1:   # was not flagged
        async with mycontext() as actx2:
            ...

The parent deferral now only applies when the parent can actually combine with the current statement: same async/sync and neither side is an exempt standalone manager (asyncio.timeout, trio cancel scopes, etc.).

Test plan

• Extended SIM117.py with regression cases for:
  • nested async under sync parent (SIM117 false negative for nested async context managers beneath a sync with parent #27800)
  • nested sync under async parent
  • nested async under exempt asyncio.timeout parent
• Updated SIM117 snapshot
• cargo test -p ruff_linter --lib multiplewithstatements

Fixes #27800

[astral-sh-bot]

ruff-ecosystem results

Linter (stable)

ℹ️ ecosystem check detected linter changes. (+9 -0 violations, +0 -0 fixes in 2 projects; 57 projects unchanged)

prefecthq/prefect (+6 -0 violations, +0 -0 fixes)

+ src/prefect/flow_engine.py:2026:13: SIM117 [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/server/utilities/test_messaging.py:307:9: SIM117 [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/server/utilities/test_messaging.py:321:9: SIM117 [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/server/utilities/test_messaging.py:397:9: SIM117 [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/workers/test_base_worker.py:4876:13: SIM117 Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/workers/test_base_worker.py:5365:13: SIM117 [*] Use a single `with` statement with multiple contexts instead of nested `with` statements

home-assistant/core (+3 -0 violations, +0 -0 fixes)

+ tests/util/test_timeout.py:126:9: SIM117 Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/util/test_timeout.py:308:9: SIM117 Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/util/test_timeout.py:318:9: SIM117 Use a single `with` statement with multiple contexts instead of nested `with` statements

Changes by rule (1 rules affected)

code	total	+ violation	- violation	+ fix	- fix
SIM117	9	9	0	0	0

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+9 -0 violations, +0 -0 fixes in 2 projects; 57 projects unchanged)

prefecthq/prefect (+6 -0 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --no-fix --output-format concise --preview

+ src/prefect/flow_engine.py:2026:13: multiple-with-statements [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/server/utilities/test_messaging.py:307:9: multiple-with-statements [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/server/utilities/test_messaging.py:321:9: multiple-with-statements [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/server/utilities/test_messaging.py:397:9: multiple-with-statements [*] Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/workers/test_base_worker.py:4876:13: multiple-with-statements Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/workers/test_base_worker.py:5365:13: multiple-with-statements [*] Use a single `with` statement with multiple contexts instead of nested `with` statements

home-assistant/core (+3 -0 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --no-fix --output-format concise --preview

+ tests/util/test_timeout.py:126:9: multiple-with-statements Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/util/test_timeout.py:308:9: multiple-with-statements Use a single `with` statement with multiple contexts instead of nested `with` statements
+ tests/util/test_timeout.py:318:9: multiple-with-statements Use a single `with` statement with multiple contexts instead of nested `with` statements

Changes by rule (1 rules affected)

code	total	+ violation	- violation	+ fix	- fix
multiple-with-statements	9	9	0	0	0

[ntBre]

Thanks, this looks good overall. I just had a few minor suggestions.

[VedantMadane]

Addressed the review notes:

1. Extracted mergeable_child and used it for both parent deferral and the nested merge check.
2. Moved the new regression cases to the end of SIM117.py so existing snapshot line numbers are unchanged.
3. Added the two-pair case (async def f(): with A(): with B(): async with C(): async with D()) expecting one diagnostic per pair.

cargo test -p ruff_linter --lib path_new_sim117 passes locally.

[ntBre]

Thank you!