Stdlib: ob_flush() / ob_clean() / ob_list_handlers() — missing OB chain builtins (ext/standard/output.c) #4838

Category

stdlib

Problem

Several output-buffer chain helpers from ext/standard/output.c are still absent. ext/standard/Module.php already registers ob_start, ob_get_contents, ob_get_length, ob_get_level, ob_get_status, ob_end_*, etc. — but ob_flush, ob_clean, and ob_list_handlers are not implemented or registered (function_exists → false).

Frameworks flush nested buffers without ending them; ob_list_handlers() introspects the stack for debugging.

Note: Refresh #3588 — its title mentions ob_get_contents but that builtin is already registered; this issue tracks the remaining three.

php-src reference

• php/php-src ext/standard/output.c — php_ob_flush, php_ob_clean, php_ob_list_handlers
• php/php-src ext/standard/basic_functions.c — registrations

Repro (failure today)

<?php
ob_start();
echo 'layer1';
ob_start();
echo 'layer2';
var_export(function_exists('ob_flush'));
var_export(function_exists('ob_clean'));
var_export(function_exists('ob_list_handlers'));

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

Nested flush probe (done-when target):

<?php
ob_start();
echo 'a';
ob_start();
echo 'b';
ob_flush();          // flush inner to parent
echo ob_get_contents(); // parent should contain ab

Scope (this repo)

• ext/standard/ob_flush.php, ob_clean.php, ob_list_handlers.php (new)
• Wire to existing OB stack (ext/standard/VmOb.php or web runtime buffer list)
• ext/standard/Module.php registration
• test/compliance/cases/stdlib/ob_flush_clean_handlers.phpt
• JIT: defer (VM-first) — update docs/capabilities.md via script/capability-matrix.php

Done when

• All three functions registered; repro function_exists → true,true,true
• Nested buffer flush/clean semantics match Zend on compliance fixture
• ./script/ci-fast.sh --filter ob_flush_clean green

Related

• Umbrella / stale title: Stdlib: ob_flush() / ob_clean() / ob_get_contents() / ob_list_handlers() — output buffer chain (ext/standard/output.c parity) #3588 (fold closed when this lands)
• ob_get_status closed Stdlib: ob_get_status() — output buffer status array (ext/standard/output.c parity) #3647 · flush() Stdlib: flush() — flush output buffers to SAPI (ext/standard/output.c parity) #3388

Links

• Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492