[labishbardiya]

Summary

Add native stack overflow protection to var_export() so deeply nested arrays and objects raise a catchable Error instead of risking a segmentation fault.

Refs GH-24605.

Root cause

php_var_export_ex() recursively processes nested structures without checking the native stack limit.

Other recursive PHP operations already use Zend's stack-limit protection.

Changes

• Add the native stack-limit guard to php_var_export_ex().
• Return FAILURE when the stack limit is exceeded.
• Propagate failures from recursive object property exports.
• Preserve cleanup on failure paths.
• Add a PHPT regression test for deeply nested arrays and objects.

Validation

Environment: macOS ARM64, PHP 8.4.28-dev, debug build.

• PHP compiled successfully.
• var_export(), print_r() and unserialize() segfault on deep nesting — the stack-limit guard from #22871 is incomplete #24605 regression test: PASS.
• Full test suite: 11,549 PASS, 1 FAIL, 3 XFAIL, 9,795 SKIP.

The unrelated unexpected failure occurred in php_ini_loaded_file.phpt. It is caused by inherited -c configuration arguments from the test harness.

The same test passes when run without those arguments. A correction is already proposed in PHP PR #24406.

The full suite has therefore not been demonstrated to pass without unexpected failures under the standard make test invocation.

Scope

This change addresses only the var_export() portion of GH-24605.

The print_r() and unserialize() cases remain outside this PR's scope.

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[ndossche]

Thanks
For the test: I think that either increasing the nesting level from 3000 to something slightly higher, or lowering the max_allowed_stack_size would make the test more robust.