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Regression: next() string-concat nested operand — returns false not element (re-#13830, ext/standard/array.c) #13912
Description
Category
stdlib · php-src-strict · regression (nested operand in string concatenation)
Problem
After advancing an array internal pointer with next(), a second next($a) as a nested operand inside string concatenation with var_export(..., true) returns false instead of the element value. Standalone next($a) returns the correct value.
Same failure class as #13903 (prev() concat, re-#13811) and #13899 (Generator::current() concat). #13830 was closed 2026-06-30 but repro still fails on master.
php-src reference
ext/standard/array.c—php_next
Repro (verified 2026-06-30)
test/repro/maintainer_gap_next_concat_operand.php
./script/docker-exec.sh -- php bin/vm.php test/repro/maintainer_gap_next_concat_operand.php| Check | Zend | VM |
|---|---|---|
$a=[1,2,3]; next($a); 'next='.var_export(next($a), true) |
next=3 |
next=false |
Standalone next($a) after one next |
2 |
correct |
Scope (PHP-in-PHP first)
| Layer | Path |
|---|---|
| VM | Pointer-builtin return binding in concat/nested-call contexts |
| Compiler | Operand lowering if mis-binding by-ref / return slot |
| JIT | after VM green |
Done when (php-src-strict)
- Repro exits 0 on VM
-
next()/prev()/current()/end()/reset()agree in concat and standalone contexts - JIT/AOT agree when in scope
Verification
./script/docker-exec.sh -- php bin/vm.php test/repro/maintainer_gap_next_concat_operand.phpLinks
- Epic Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 · siblings Regression: prev() string-concat nested operand — returns false not element (re-#13811, ext/standard/array.c) #13903, Regression: Generator::current()/::key() string-concat nested operand — returns true not yielded value (Zend/zend_generators.c) #13899, closed Regression: next() string-concat nested operand — returns true not element (ext/standard/array.c) #13830
Activity
Fix duplicate callee sibling chain for var_export concat operands (#1…
PurHur commentedon Jun 30, 2026
Root cause fixed in #13916 / #13917 (compiler
firstSiblingInlineFuncCallProducerIndex). Reprotest/repro/maintainer_gap_next_concat_operand.phpexits 0 on master after merge.Add prev() concat operand repro and PHPUnit guard (#13903). (#13922)
PurHur commentedon Jun 30, 2026
Verified on master (2026-06-30):
php bin/vm.php test/repro/maintainer_gap_next_concat_operand.php→ ok;testVarExportNestedNextUsesFuncCallProducerSlotgreen. Compiler fix viastatementLevelFuncCallBeforeHoistedSiblingChain. Closing candidate — sibling #13903 guard merged #13922.PurHur commentedon Jun 30, 2026
Verified on master 2026-06-30:
php bin/vm.php test/repro/maintainer_gap_next_concat_operand.php→ ok (exit 0). Fixed via #13916/#13917 compiler sibling-call producer slot. Closing.