Regression: AOT DateTime::diff() fails after two locals — New_ resultOp unnamed so construct stamps never bind (re-#27309) #33906

Category

bug · php-src-strict · AOT / ext/date (re-#27309)

Problem

After #32691 moved DateTime construct stamps onto compileTimeDateTimeTimestamp, thin AOT again fails the #27309 fixture whenever two DateTime locals are constructed before diff:

$a = new DateTime('2024-01-01');
$b = new DateTime('2024-01-10');
echo $a->diff($b)->days;

Root cause: syncDateTimeConstructMetaToAliases only published dateTimeLocalInstants when lastDateTimeNewResultOp had an Operand name. Temporary New_ results are often unnamed, and named bindings for $a/$b are different Variable objects than the construct $this, so identity matching never recorded the local. $a->diff($b) then saw a receiver with no stamp (str='DateTime' only).

php-src reference

• php/php-src ext/date/php_date.c — zim_DateTime_diff / date_diff

PHP implementation target

• lib/JIT.php — syncDateTimeConstructMetaToAliases: publish instant onto the first unstamped DateTime-shaped named binding when New_ has no name
• ext/standard/JitDateMutation.php — prefer compileTimeDateTimeTimestamp; runtime __phpc_date_diff_scalars fallback outside thin user AOT
• Keep AOT: DatePeriod foreach SIGABRTs — snapshot still reads compileTimeLong after DateTime timestamp field split (re-#26937, ext/date/php_date.c) #33744 invariant: never clobber an already-stamped sibling local

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && ./phpc build -o /tmp/d.bin test/repro/issue_33910_datetime_diff_two_locals_aot.php && /tmp/d.bin'

Done when

• AOT prints 9 for the two-local repro
• vendor/bin/phpunit --filter datetime_diff_days test/aot/AotTest.php OK
• DatePeriod foreach two-bound construct still matches Zend (2020-01-01|…)