Requests That End Wrong: A 200 That Was Really a Crash

Thu, 13 Aug 2026 21:14:00 -0700

The scariest response a server can send isn’t a 500. It’s a 200 that should have been a 500. A crash is loud. The pod restarts, an alert fires, somebody looks. A truncated page with a success status code is quiet. Your CDN caches it and the health check calls the box healthy. A client parses half a document as if it were the whole thing.

ePHPm embeds PHP inside a Rust server. So we own the part of PHP that php-fpm normally owns: starting a request, running the script and ending it. Over the last couple of months I’ve fixed three bugs that all live in that start-and-end code. None of them were in the SAPI I/O callbacks like ub_write and read_post, where you’d expect to find embed bugs. They were in the Zend request lifecycle and in TSRM teardown. That’s code you never touch when you run PHP behind php-fpm.

Zend on Luther Monson

Requests That End Wrong: A 200 That Was Really a Crash