[Bug]: php_herd-X.X.dll causes php-cgi to crash on startup (exit code 4294967295) — all sites return 504

[Ahmad-Chebbo]

Platform

Windows

Operating system version

Windows 11

System architecture

Intel (x86)

Herd Version

1.28.0

PHP Version

No response

Bug description

Bug: php_herd-X.X.dll causes php-cgi to crash on startup (exit code 4294967295) — all sites return 504

Herd version: 1.28.0
OS: Windows 11
PHP versions affected: All (7.4, 8.0, 8.1, 8.2, 8.3, 8.4)

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Description

After a fresh install of Herd 1.28.0 on Windows, all sites return 504 Gateway Timeout. The Herd CLI (herd --version, herd doctor, etc.) freezes indefinitely. Changing PHP version per site via the GUI appears to work visually but does not persist after restarting Herd.

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Root cause identified

The php_herd-X.X.dll extension (loaded via php.ini) causes php-cgi.exe to exit immediately with code 4294967295 (0xFFFFFFFF / -1) when spawned by the Herd Electron process.

From main.log:

[info]  [PHP] Starting PHP 84 on port 9084
[info]  Started PHP-8.4 with PID 45948
[info]  PHP-8.4 exited with code 4294967295 - PID: 45948

This crash happens on every spawn attempt. Since php-cgi never binds to port 9084, nginx cannot forward requests and returns 504.

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What works vs what doesn't

Scenario	Result
php-cgi.exe -b 127.0.0.1:9084 (manual, DLL enabled)	Crashes immediately
php-cgi.exe -b 127.0.0.1:9084 (manual, DLL disabled)	Works, port binds correctly
php-cgi.exe -m (list modules, DLL enabled)	Works fine, all modules load
Herd spawning php-cgi (DLL enabled)	Crashes with code 4294967295
Herd spawning php-cgi (DLL disabled)	Works, sites load correctly
herd --version (DLL disabled)	Freezes — herd.phar depends on the DLL

The DLL loads fine in non-FastCGI mode (-m, -v) but crashes when php-cgi is started as a FastCGI server via -b. This only happens when spawned by Herd — manual launch with identical arguments and environment variables (PHP_FCGI_CHILDREN=4, PHP_FCGI_MAX_REQUESTS=1000) also crashes.

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Impact

• All sites return 504 (php-cgi never binds to port)
• Herd CLI completely frozen (herd.phar depends on php_herd DLL for IPC)
• Per-site PHP version changes do not persist (CLI required to save)

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Workaround

Comment out the php_herd extension in all PHP version php.ini files:

;extension = 'C:\Program Files\Herd\resources\app.asar.unpacked\resources\bin\phpherd\php_herd-8.4.dll'

Sites work after this change but the CLI and per-site PHP version switching remain broken.

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Environment

• CPU: AMD64 Family 25 Model 68 (Ryzen)
• Windows Defender exclusions added for both Herd folders — no change in behavior
• Fresh install (previous installation fully removed)
• PHP binaries location: C:\Users\<user>\.config\herd\bin\php84\
• DLL location: C:\Program Files\Herd\resources\app.asar.unpacked\resources\bin\phpherd\

Steps to reproduce

No response

Relevant log output