Narrow types after strlen()#5703
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…ArrayDimFetchCheck` "might not exist" report
- In the `reportMaybes` decomposition loop of `NonexistentOffsetInArrayDimFetchCheck`,
when flattened union members are checked individually, skip reporting for string types
with integer offsets where a specific member returns `no` for `hasOffsetValueType`
- The union-level `hasOffsetValueType` already correctly returns `maybe` for these cases;
the decomposition adds no new information for strings and produces false positives
when one union member (e.g. empty string) is shorter than the offset
- Example: `(''|':')[0]` — union-level returns `maybe`, decomposition found `''` returns
`no` for offset 0 and incorrectly escalated to "might not exist" report
- Definitive `no` results (single string, non-integer offset) are unaffected
- Regression test covers the original issue pattern and string union variants
staabm
reviewed
May 18, 2026
…uthy context Revert the rule-level fix that skipped string-with-integer-offset checks in NonexistentOffsetInArrayDimFetchCheck. Instead, teach the TypeSpecifier to narrow strlen()/mb_strlen() arguments to non-empty-string when the result is used in a truthy context. This enables the existing ConditionalExpressionHolder machinery to propagate the narrowing through variable assignments like `$len = strlen($x); if ($len > 0)`. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
staabm
reviewed
May 19, 2026
…xtension Extract the inline strlen/mb_strlen non-empty-string narrowing from TypeSpecifier::specifyTypesInCondition() into a proper FunctionTypeSpecifyingExtension, following the same pattern as CountFunctionTypeSpecifyingExtension. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
staabm
reviewed
May 19, 2026
staabm
changed the title
NonexistentOffsetInArrayDimFetchCheck "might not exist" report…texts Cover all context types: direct truthy/falsey, negation, boolean and/or, ternary, loose comparison with true/false, mb_strlen, and non-string input handling. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
staabm
approved these changes
May 19, 2026
staabm
reviewed
May 19, 2026
staabm
reviewed
May 19, 2026
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Fixes phpstan/phpstan#13688