Stdlib: array_fill_keys() resource keys — must stringify 'Resource id #N' not Error (ext/standard/array.c)

[PurHur]

Summary

When array_fill_keys() receives a resource in the keys list, Zend coerces it to the string "Resource id #N" (with E_WARNING in some builds) and builds the result hash. VM throws Error: Object of class Resource could not be converted to string instead.

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro/maintainer_gap_array_fill_keys_resource.php
php bin/vm.php test/repro/maintainer_gap_array_fill_keys_resource.php'

Call	Zend PHP 8.2	VM today
array_fill_keys([$stream], 1)	array('Resource id #5' => 1)	Error ❌

php-src reference

• php/php-src ext/standard/array.c — php_array_fill_keys, _array_to_string / resource key coercion via ZVAL_LONG hash key path

Implementation (PHP-in-PHP)

• ext/standard/VmArray.php — array_fill_keys key coercion: resources → "Resource id #" + id (match VmResource / print_r formatting)
• Share helper with other builtins that accept hash keys (array_combine already errors correctly on objects — only resource path differs)
• No new C runtime

Done when (php-src-strict)

• Repro returns array('Resource id #N' => 1) on VM
• Object keys still Error (not regressed)
• JIT/AOT agree when in scope

Verification

./script/docker-exec.sh -- php bin/vm.php test/repro/maintainer_gap_array_fill_keys_resource.php

Related: #8779 (enum keys), #1492

[PurHur]

claim: PHP Compiler STD Lib — starting this run

[PurHur]

Merged via #10856.

Verification (VM + JIT green):

• Repro: php bin/vm.php test/repro/maintainer_gap_array_fill_keys_resource.php → array('Resource id #1' => 1)
• Unit: ArrayFillKeysBuiltinTest::testFillKeysResourceKeyStringifiesLikeZend
• Compliance: array_fill_keys_resource + array_fill_keys_resource_jit PHPTs
• Enum key regression: array_fill_keys_enum still Error
• AOT lint: php bin/compile.php -l test/repro/maintainer_gap_array_fill_keys_resource.php

Implementation: VmVarFormat::tryFormatPrintR in VmArray::storeCombineKey; JIT formatResourceIdStringKey in ArrayBuiltinHelper::storeCombinedEntry.