Fix phpstan/phpstan#13591: False positive: Type narrowing not working with conditional exception validation#5385
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…l exception validation - When a compound condition like `$x === null && ($y === 'a' || $y === 'b')` throws, the negation creates conditional holders with union condition types (e.g. $y: 'a'|'b') - These union conditions could never be matched exactly by later narrowing like `$y === 'a'` - Fix: expand union condition types in conditional holders into separate holders for each union member, while keeping the original union holder for exact matches - New regression test in tests/PHPStan/Analyser/nsrt/bug-13591.php
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Summary
When a compound condition like
if ($hotelId === null && ($action === 'get_rooms' || $action === 'update')) { throw ...; }guards subsequent code, PHPStan should narrow$hotelIdto non-null when$action === 'get_rooms'. This wasn't happening because the conditional expression holders created union condition types that couldn't be matched by more specific type narrowings.Changes
processBooleanSureConditionalTypesandprocessBooleanNotSureConditionalTypesinsrc/Analyser/TypeSpecifier.phpto expand union condition types into separate holdersexpandUnionConditionshelper method that takes a condition set and produces additional holder variants for each member of any union types in the conditionsRoot cause
When
$hotelId === null && ($action === 'get_rooms' || $action === 'update')is evaluated in the falsey context (after throwing), theprocessBooleanNotSureConditionalTypesmethod creates a conditional expression holder with condition{$action: 'get_rooms'|'update'}and result{$hotelId: int}. This means "if $action is exactly'get_rooms'|'update', then $hotelId is int".However, when entering
if ($action === 'get_rooms'), the scope narrows$actionto'get_rooms'— a single constant type, not the union'get_rooms'|'update'. Theequalscheck infilterBySpecifiedTypesrequires exact type equality, so the holder never matches.The fix expands the union condition into separate holders: one for
{$action: 'get_rooms'}and one for{$action: 'update'}, each pointing to the same result. This way, enteringif ($action === 'get_rooms')matches the first expanded holder exactly.Test
Added
tests/PHPStan/Analyser/nsrt/bug-13591.php— an NSRT test that verifies$hotelIdis narrowed toint(notint|null) insideif ($action === 'get_rooms')after the throwing guard.Fixes phpstan/phpstan#13591