[flake8-pytest-style] Make fixes safe by default and unsafe only when comments are present (PT018)

[jesco-absolut]

Summary

Fixes #20698.

• Default Fix Safety: The PT018 rule splits composite assertions into individual assert statements. Because standard transformations (without custom messages) maintain short-circuiting and original runtime behavior, these fixes are now classified as safe by default, rather than marking every fix as unsafe.
• Handling Comments: Previously, Ruff completely disabled fixes for assertions containing comments. Now, assertions with internal comments will still offer a fix, but marked with an unsafe classification to ensure user verification while preserving functionality.

Proposed fixed will now composite assertion with an internal comment. Ordinary transformations are safe while the comment-bearing case receives an unsafe fix and this is verified.

Test Plan

• Ran the focused PT018 fixture and snapshot test:
  cargo test -p ruff_linter --lib rule_pytestcompositeassertion_path_new_pt018_py_settings_default_pt018_expects
• Ran cargo fmt --all --check

[astral-sh-bot]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+53 -53 violations, +0 -0 fixes in 3 projects; 54 projects unchanged)

bokeh/bokeh (+21 -21 violations, +0 -0 fixes)

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

- tests/unit/bokeh/application/handlers/test_server_lifecycle.py:184:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/application/handlers/test_server_lifecycle.py:184:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/application/handlers/test_server_request_handler.py:98:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/application/handlers/test_server_request_handler.py:98:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/command/subcommands/test_settings__subcommands.py:96:5: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/command/subcommands/test_settings__subcommands.py:96:5: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/core/property/test_wrappers__property.py:178:5: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/core/property/test_wrappers__property.py:178:5: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/core/test_json_encoder.py:41:5: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/core/test_json_encoder.py:41:5: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/embed/test_standalone.py:406:13: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/embed/test_standalone.py:406:13: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/embed/test_standalone.py:413:13: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/embed/test_standalone.py:413:13: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/io/test_export.py:257:5: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/io/test_export.py:257:5: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/io/test_export.py:471:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ tests/unit/bokeh/io/test_export.py:471:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- tests/unit/bokeh/models/test_sources.py:513:9: pytest-composite-assertion Assertion should be broken down into multiple parts
... 23 additional changes omitted for project

latchbio/latch (+1 -1 violations, +0 -0 fixes)

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

- src/latch_cli/services/register/register.py:256:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ src/latch_cli/services/register/register.py:256:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts

zulip/zulip (+31 -31 violations, +0 -0 fixes)

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

- corporate/lib/stripe.py:1315:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ corporate/lib/stripe.py:1315:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- corporate/lib/stripe.py:1420:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ corporate/lib/stripe.py:1420:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- corporate/lib/stripe.py:4337:13: pytest-composite-assertion Assertion should be broken down into multiple parts
+ corporate/lib/stripe.py:4337:13: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- corporate/lib/stripe.py:805:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ corporate/lib/stripe.py:805:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/actions/user_settings.py:191:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/actions/user_settings.py:191:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/bot_lib.py:162:5: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/bot_lib.py:162:5: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/email_notifications.py:691:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/email_notifications.py:691:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/email_notifications.py:877:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/email_notifications.py:877:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/email_notifications.py:933:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/email_notifications.py:933:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/export.py:699:13: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/export.py:699:13: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/import_realm.py:699:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/import_realm.py:699:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/notification_data.py:38:13: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/notification_data.py:38:13: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/notification_data.py:51:13: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/notification_data.py:51:13: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/push_notifications.py:1081:9: pytest-composite-assertion Assertion should be broken down into multiple parts
+ zerver/lib/push_notifications.py:1081:9: pytest-composite-assertion [*] Assertion should be broken down into multiple parts
- zerver/lib/push_notifications.py:150:13: pytest-composite-assertion Assertion should be broken down into multiple parts
... 33 additional changes omitted for project

Changes by rule (1 rules affected)

code	total	+ violation	- violation	+ fix	- fix
pytest-composite-assertion	106	53	53	0	0

[ntBre]

This is a stable rule, so we have to make this change in preview in accordance with our Versioning policy.

[ntBre]

Thank you!