Regression: Reflection DNF/(int\|null) type strings diverge from Zend (ext/reflection/php_reflection.c)

[PurHur]

Category

Regression · php-src-strict · language · Reflection · pillar 4

Problem

ReflectionType::__toString() (via (string)$type) diverges from Zend for two cases that already parse/compile:

1. DNF parentheses — Zend keeps grouping parens around an intersection in a union; VM drops them.
2. int|null normalization — Zend stringifies int|null as ?int; VM keeps int|null (?int shorthand still matches).

Verified 2026-07-25 (host Zend PHP 8.2.32 vs php bin/vm.php):

Repro	Zend 8.2+	VM
(string) of (Traversable&Countable)|array param	(Traversable&Countable)|array	Traversable&Countable|array (parens missing)
(string) of int|null param	?int	int|null
(string) of ?int param	?int	?int (same)

php-src reference

• php/php-src ext/reflection/php_reflection.c — ReflectionType / union / intersection / DNF stringification
• Related prior work: Stdlib: ReflectionUnionType / ReflectionIntersectionType — getTypes() parity (ext/reflection/php_reflection.c) #4650, Language: ReflectionUnionType::allowsNull true for int\|string — Zend false (ext/reflection) #22851 (allowsNull); this is remaining __toString shape parity

PHP implementation target

• Reflection type __toString / name rendering in ext/reflection (PHP) — emit Zend-identical DNF parentheses and ?T for single-named |null unions
• PHP-in-PHP; no new runtime/*.c

Repro

./script/docker-exec.sh -- bash -lc 'cat > /tmp/reflect_type_str.php <<'"'"'PHP'"'"'
<?php
function f((Traversable&Countable)|array $x) {}
function g(int|null $x) {}
function h(?int $x) {}
echo (string)(new ReflectionFunction("f"))->getParameters()[0]->getType(), "\n";
echo (string)(new ReflectionFunction("g"))->getParameters()[0]->getType(), "\n";
echo (string)(new ReflectionFunction("h"))->getParameters()[0]->getType(), "\n";
PHP
php bin/vm.php /tmp/reflect_type_str.php
# expect:
# (Traversable&Countable)|array
# ?int
# ?int

Done when

• DNF union string includes Zend parentheses around the intersection group
• int|null (and null|int) stringifies as ?int
• Compliance .phpt under test/compliance/cases/reflection/
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: Lane B implementer (Composer) — starting this run

Trust snapshot (pre-claim):

• php script/bootstrap-inventory.php --check — file-list drift / construct-flag noise (not clean OK line yet)
• ./script/release-readiness.sh --json — still running
• Prefer Regression: Reflection DNF/(int\|null) type strings diverge from Zend (ext/reflection/php_reflection.c) #23065 over Regression: ReflectionProperty::isFinal() false for public private(set) — Zend implicit final (ext/reflection/php_reflection.c) #23068 (same lane; lower number; no claim)

[PurHur]

Merged via #23090

Verification:

• php bin/vm.php test/repro/issue_23065_reflection_type_tostring.php → (Traversable&Countable)|array / ?int / ?int (matches Zend)
• ./script/phpunit.sh --filter 'ReflectionTypesTest|reflection_type_tostring_dnf_null' → OK (5 tests)

Fix: ReflectionTypeSupport::cfgTypeString DNF parens + union __toString via cfgTypeStringForDump (?T for T|null).