Assertion failure in check_node_running_in_fiber() when resuming a generator inside a Fiber destructor
Open
Nobody has claimed this yet.
Bug
Category: Engine
Status: Verified
- Dominant language
- C
- Stars
- 40.4k
- Forks
- 8.1k
- Avg merge
- 2d 13h
- Merged PRs (30d)
- 96
Description
Description
The following code:
<?php
class a {
static $b;
static $max = 5.;
function __destruct() {
$a = new a;
static $gen = (function() {
$from = (function () {
$a = new a;
yield;
})();
try {
yield from $from;
} finally {
}
})();
$fiber = new Fiber(function () use ($gen, &$fiber) {
$gen->next();
});
$fiber->start();
}
}
new a;
Resulted in this output:
php: /path/to/php-src/Zend/zend_generators.c:217: _Bool check_node_running_in_fiber(zend_generator *): Assertion `generator->execute_data' failed.
Aborted
Commit:
56795d2810e
Build configuration:
CC="clang" CXX="clang++" CFLAGS="-fsanitize=address -g -O0" CXXFLAGS="-fsanitize=address -g -O0" LDFLAGS="-fsanitize=address" ./buildconf --force && ./configure --enable-debug --enable-address-sanitizer --disable-shared --with-pic --enable-mbstring --with-zlib
PHP Version
PHP 8.6.0-dev (cli) (built: Nov 29 2025 14:32:34) (NTS DEBUG)
Copyright (c) The PHP Group
Zend Engine v4.6.0-dev, Copyright (c) Zend Technologies
with Zend OPcache v8.6.0-dev, Copyright (c), by Zend Technologies
Operating System
Ubuntu 22.04
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start at Zend/zend_generators.c around check_node_running_in_fiber() line 217, then reproduce the provided script with the debug and AddressSanitizer configuration. Trace the generator and Fiber lifecycle during object destruction; done means the reproducer no longer aborts on the assertion and regression coverage verifies the behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c, php
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100