Avoid infinite loop between `I002` and `PYI025` by kar-ganap · Pull Request #23352 · astral-sh/ruff

kar-ganap · 2026-02-16T20:49:19Z

Summary

Fixes #20891.

When lint.isort.required-imports includes from collections.abc import Set (unaliased) and PYI025 is enabled, the two rules conflict: I002 inserts the unaliased import, while PYI025 demands it be aliased as AbstractSet. This causes an infinite autofix loop ("Failed to converge after 100 iterations").

Rather than patching the import-insertion logic at the rule level, this PR rejects the contradictory configuration at startup in Configuration::into_settings(), following the existing pattern established by conflicting_import_settings(). The error message explains the conflict and suggests two resolutions: alias the required import as AbstractSet, or disable PYI025.

Prior art

PR #21115 took a different approach (modifying add_required_imports.rs and imports.rs to relax alias matching). As noted in review, the better fix is to "reject this configuration entirely at an earlier stage" since it doesn't make sense to simultaneously require an unaliased import and forbid it. This PR implements that suggestion directly.

Test plan

3 unit tests: conflicting config → error, aliased as AbstractSet → ok, PYI025 not enabled → ok
Reproduction case: ruff check --config ruff.toml --unsafe-fixes --fix now emits a clear configuration error instead of entering the infinite loop
cargo test -p ruff_workspace — all 26 tests pass

Fixes astral-sh#20891. When `lint.isort.required-imports` includes `from collections.abc import Set` (unaliased) and PYI025 is enabled, the two rules conflict: I002 inserts the unaliased import, while PYI025 demands it be aliased as `AbstractSet`. This causes an infinite autofix loop. Rather than patching the import-insertion logic, reject this contradictory configuration at startup in `Configuration::into_settings`, following the existing pattern of `conflicting_import_settings()`. The new `conflicting_required_import_pyi025()` function checks for the specific conflict and emits a clear error message with a suggested fix. Aliasing the required import as `AbstractSet` (satisfying both rules) or disabling PYI025 are both accepted configurations.

astral-sh-bot · 2026-02-17T03:33:38Z

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kar-ganap · 2026-02-22T23:24:25Z

Gentle ping — this has been open since Feb 16 with clean CI and zero ecosystem impact. The approach follows the pattern suggested in #20891 (reject conflicting configuration at startup rather than working around it at the rule level). Would appreciate a review when someone has a chance.

ntBre

Thanks, this looks good overall. I just had one testing suggestion.

ntBre · 2026-02-23T14:57:13Z

crates/ruff_workspace/src/configuration.rs

        Ok(())
    }
+
+    mod pyi025_conflict {


Let's just add CLI tests like these:

ruff/crates/ruff/tests/cli/lint.rs

Lines 2842 to 2872 in 7778f65

#[test]

fn flake8_import_convention_unused_aliased_import() {

assert_cmd_snapshot!(

Command::new(get_cargo_bin(BIN_NAME))

.args(STDIN_BASE_OPTIONS)

.arg("--config")

.arg(r#"lint.isort.required-imports = ["import pandas"]"#)

.args(["--select", "I002,ICN001,F401"])

.args(["--stdin-filename", "test.py"])

.arg("--unsafe-fixes")

.arg("--fix")

.arg("-")

.pass_stdin("1")

);

}

#[test]

fn flake8_import_convention_unused_aliased_import_no_conflict() {

assert_cmd_snapshot!(

Command::new(get_cargo_bin(BIN_NAME))

.args(STDIN_BASE_OPTIONS)

.arg("--config")

.arg(r#"lint.isort.required-imports = ["import pandas as pd"]"#)

.args(["--select", "I002,ICN001,F401"])

.args(["--stdin-filename", "test.py"])

.arg("--unsafe-fixes")

.arg("--fix")

.arg("-")

.pass_stdin("1")

);

}

That will also get us snapshots to verify the full contents of the error message.

Done — replaced the unit tests with CLI snapshot tests in crates/ruff/tests/cli/lint.rs, following the pattern from the existing flake8_import_convention_unused_aliased_import tests. Three tests:

required_import_set_conflicts_with_pyi025 — unaliased Set + PYI025 → exit code 2 with error message

required_import_set_aliased_as_abstract_set_no_conflict — aliased as AbstractSet → no config error

required_import_set_without_pyi025_no_conflict — PYI025 not selected → no config error

Move PYI025 conflict tests from ruff_workspace unit tests to CLI integration tests using assert_cmd_snapshot!, matching the pattern used by the existing flake8-import-conventions conflict tests.

ntBre

Thanks!

kar-ganap force-pushed the fix/issue-20891 branch from 2d42908 to f19b5e7 Compare February 17, 2026 03:20

ntBre added bug Something isn't working fixes Related to suggested fixes for violations labels Feb 23, 2026

ntBre reviewed Feb 23, 2026

View reviewed changes

Replace unit tests with CLI snapshot tests per review feedback

eac0493

Move PYI025 conflict tests from ruff_workspace unit tests to CLI integration tests using assert_cmd_snapshot!, matching the pattern used by the existing flake8-import-conventions conflict tests.

ntBre approved these changes Feb 24, 2026

View reviewed changes

ntBre changed the title ~~Reject conflicting I002 + PYI025 configuration at startup~~ Avoid infinite loop between I002 and PYI025 Feb 24, 2026

ntBre merged commit df313c2 into astral-sh:main Feb 24, 2026
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BrewTestBot mentioned this pull request Feb 26, 2026

ruff 0.15.3 Homebrew/homebrew-core#269612

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Avoid infinite loop between `I002` and `PYI025` #23352

Avoid infinite loop between `I002` and `PYI025` #23352
ntBre merged 2 commits intoastral-sh:mainfrom
kar-ganap:fix/issue-20891

kar-ganap commented Feb 16, 2026

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	#[test]
	fn flake8_import_convention_unused_aliased_import() {
	assert_cmd_snapshot!(
	Command::new(get_cargo_bin(BIN_NAME))
	.args(STDIN_BASE_OPTIONS)
	.arg("--config")
	.arg(r#"lint.isort.required-imports = ["import pandas"]"#)
	.args(["--select", "I002,ICN001,F401"])
	.args(["--stdin-filename", "test.py"])
	.arg("--unsafe-fixes")
	.arg("--fix")
	.arg("-")
	.pass_stdin("1")
	);
	}

	#[test]
	fn flake8_import_convention_unused_aliased_import_no_conflict() {
	assert_cmd_snapshot!(
	Command::new(get_cargo_bin(BIN_NAME))
	.args(STDIN_BASE_OPTIONS)
	.arg("--config")
	.arg(r#"lint.isort.required-imports = ["import pandas as pd"]"#)
	.args(["--select", "I002,ICN001,F401"])
	.args(["--stdin-filename", "test.py"])
	.arg("--unsafe-fixes")
	.arg("--fix")
	.arg("-")
	.pass_stdin("1")
	);
	}

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kar-ganap commented Feb 16, 2026

Summary

Prior art

Test plan

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astral-sh-bot bot commented Feb 17, 2026 •

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