Support reportUnmatchedIgnoredErrors: warning to report unmatched ignores as warnings instead of errors

[phpstan-bot]

Summary

Adds support for setting reportUnmatchedIgnoredErrors to 'warning' (in addition to true/false). When set to 'warning', unmatched baseline entries and unmatched @phpstan-ignore line comments are reported as warnings instead of errors, allowing the build to stay green while still informing the user about stale ignore patterns.

This enables a workflow where teams can safely regenerate baselines without introducing new errors — unmatched ignores are visible but non-blocking, removing the need to temporarily toggle reportUnmatchedIgnoredErrors: false.

Changes

Config schema

• conf/parametersSchema.neon: Updated both reportUnmatchedIgnoredErrors and per-error reportUnmatched to accept anyOf(bool(), 'warning')

Core logic

• src/Analyser/Ignore/IgnoredErrorHelper.php: Changed $reportUnmatchedIgnoredErrors from bool to bool|string. Added mergeReportUnmatched() for proper precedence during deduplication (true > 'warning' > false)
• src/Analyser/Ignore/IgnoredErrorHelperResult.php: Changed type to bool|string. Updated process() to route unmatched config-level ignores to a $warnings array when reportUnmatched === 'warning'
• src/Analyser/Ignore/IgnoredErrorHelperProcessedResult.php: Added $warnings constructor parameter and getWarnings() method
• src/Analyser/AnalyserResultFinalizer.php: Changed type to bool|string. Updated addUnmatchedIgnoredErrors() to route unmatched line-level ignores to warnings
• src/Analyser/FinalizerResult.php: Added $warnings constructor parameter and getWarnings() method
• src/Command/AnalyseApplication.php: Merged warnings from FinalizerResult and IgnoredErrorHelperProcessedResult into AnalysisResult
• src/DependencyInjection/ValidateIgnoredErrorsExtension.php: Updated to validate paths when setting is 'warning' (not just true)

Analogous cases probed

• reportIgnoresWithoutComments: Different concern (requiring comments on @phpstan-ignore), not extended with 'warning' — it doesn't relate to the baseline workflow described in the issue
• Per-error reportUnmatched: Extended to also accept 'warning', including proper merge logic during deduplication

Root cause

The reportUnmatchedIgnoredErrors setting only supported true/false. Users who wanted to see unmatched baseline entries without failing the build had to temporarily change this to false before regenerating the baseline — a workflow that doesn't scale to larger teams. The 'warning' value provides a middle ground: unmatched ignores are visible in the output but don't cause a non-zero exit code.

Test

Added 4 regression tests in tests/PHPStan/Analyser/AnalyserTest.php:

• testReportUnmatchedIgnoredErrorsWarningGlobal: Verifies global 'warning' setting produces warnings (not errors) for unmatched patterns
• testReportUnmatchedIgnoredErrorsWarningPerError: Verifies per-error reportUnmatched: 'warning' produces warnings
• testReportUnmatchedIgnoredErrorsWarningPerErrorRaw: Same for rawMessage patterns
• testReportUnmatchedIgnoredErrorsWarningLine: Verifies 'warning' setting produces warnings for unmatched @phpstan-ignore line comments

Fixes phpstan/phpstan#9695

[staabm]

@phpstan-bot I think we should solve this different. revert all the changes and instead implement a new CLI option which allows to regenerate the baseline in a way that outdated errors are ignored, but no new errors will be recorded in the baseline