Fatal error during autoloading of complex inheritance chain with LSP checks since PHP 8.1.0 #20112
Description
Description
The following code:
<?php
$depth = 0;
spl_autoload_register(function ($class) use (&$depth) {
$depth++;
$indent = str_repeat('| ', $depth);
echo $indent."$depth: $class\n";
if ($class == 'IFace') {
interface IFace {}
} elseif ($class == 'IFaceImplementor') {
class IFaceImplementor implements IFace {}
} elseif ($class == 'InterfaceOfMainParent') {
interface InterfaceOfMainParent
{
public function methodForSecondaryLspCheck(): IFace;
}
} elseif ($class == 'MainParent') {
abstract class MainParent implements InterfaceOfMainParent
{
public function methodForSecondaryLspCheck(): IFaceImplementor {}
}
} elseif ($class == 'Intermediate') {
abstract class Intermediate extends MainParent {}
} elseif ($class == 'Child1') {
class Child1 extends Intermediate {}
} elseif ($class == 'Child2') {
class Child2 extends Intermediate {}
} elseif ($class == 'EntrypointParent') {
abstract class EntrypointParent
{
abstract public function methodForLspCheck1(): MainParent;
abstract public function methodForLspCheck2(): MainParent;
}
} elseif ($class == 'Entrypoint') {
class Entrypoint extends EntrypointParent
{
public function methodForLspCheck1(): Child1 {}
public function methodForLspCheck2(): Child2 {}
}
}
$depth--;
});
class_exists(Entrypoint::class);Resulted in this output:
| 1: Entrypoint
| | 2: EntrypointParent
| | 2: Child1
| | | 3: Intermediate
| | | | 4: MainParent
| | | | | 5: InterfaceOfMainParent
| | | | | 5: Child2
Fatal error: During inheritance of MainParent, while autoloading Child2: Uncaught Error: Class "Intermediate" not found in php-wasm run script:29
Stack trace:
#0 php-wasm run script(20): {closure}('Child2')
#1 php-wasm run script(25): {closure}('MainParent')
#2 php-wasm run script(27): {closure}('Intermediate')
#3 php-wasm run script(37): {closure}('Child1')
#4 [internal function]: {closure}('Entrypoint')
#5 php-wasm run script(47): class_exists('Entrypoint')
#6 {main} in php-wasm run script on line 20
But I expected this output instead:
| 1: Entrypoint
| | 2: EntrypointParent
| | 2: Child1
| | | 3: Intermediate
| | | | 4: MainParent
| | | | | 5: InterfaceOfMainParent
| | | | | 5: IFaceImplementor
| | | | | | 6: IFace
| | 2: Child2
- Full reproduction repository: https://github.com/janedbal/php-bug-complex-inheritance-chain-autoloading
- 3v4l version: https://3v4l.org/G5fFe
- Broken since: PHP 8.1.0
PHP Version
PHP 8.5.0RC1 (cli) (built: Oct 8 2025 22:41:41) (NTS)
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