PHP8.1.3. opcache bug with monolog/monolog

[R4c00n]

Description

Using monolog/monolog on PHP8.1.3 results in some very weird problems with the class vendor/monolog/monolog/src/Monolog/DateTimeImmutable.php not being found.
There's also already a bugreport in monolog Seldaek/monolog#1626, but it looks like this is an opcache bug.

Our deployment process looks like this:

• Upload files to server into release directory
• symlink release directory
• reset opcache (opcache_reset)

After that, we get the PHP message: PHP Fatal error: Uncaught Error: Class "Monolog\DateTimeImmutable" not found in ... error.
Resetting opcache a second time fixes the bug and everything is fine until the next deployment.

PHP Version

PHP 8.1.3

Operating System

Debian

[R4c00n]

Also: With PHP7.4 and same opcache settings the same workflow & code is working

[cmb69]

Is a file cache involved?

[R4c00n]

All file_cache settings are on default, so should be turned off.

; ...
;opcache.file_cache=

; Enables or disables opcode caching in shared memory.
;opcache.file_cache_only=0

; Enables or disables checksum validation when script loaded from file cache.
;opcache.file_cache_consistency_checks=1

; Implies opcache.file_cache_only=1 for a certain process that failed to
; reattach to the shared memory (for Windows only). Explicitly enabled file
; cache is required.
;opcache.file_cache_fallback=1
; ...

[cmb69]

Thanks for the further info! Did you check the return value of opcache_reset() (i.e. did it return true?) Are there any relevant messages in opcache.error_log (please also check with opcache.log_verbosity_level=4).

[temp]

Same problem here, no file cache, will check with log and verbosity.

[R4c00n]

opcache_reset returns true, both during release and also when executing manually
The logs also look good.

Here are some logs with grep for the file in question:
After release (when it's broken) we get:

Thu Mar  3 10:51:49 2022 (24268): Message Cached script '/home/xxx/release-2882/vendor/monolog/monolog/src/Monolog/DateTimeImmutable.php'
Thu Mar  3 10:51:49 2022 (24268): Message Added key '/home/xxx/release-2882/vendor/composer/../monolog/monolog/src/Monolog/DateTimeImmutable.php'

After manual reset (when it works again) this gets added:

Thu Mar  3 10:57:23 2022 (24272): Message Cached script '/home/xxx/release-2882/vendor/monolog/monolog/src/Monolog/DateTimeImmutable.php'
Thu Mar  3 10:57:23 2022 (24272): Message Added key '/home/xxx/release-2882/vendor/composer/../monolog/monolog/src/Monolog/DateTimeImmutable.php'