Enable opcache by default

[TimWolla]

OPcache is an essential part of modern PHP and will always be included in PHP starting with 8.5 (https://wiki.php.net/rfc/make_opcache_required). Enable OPcache by default in Docker to simplify the set-up.

---

I've verified that running docker-php-ext-install opcache and docker-php-ext-enable opcache in a custom Docker image based on the PHP image will not cause issues.

[tianon]

Can you elaborate on this (seemingly unrelated) change? The .so vs not-.so is already handled in docker-php-ext-enable unless I've missed something.

[TimWolla]

Without this change, this would call docker-php-ext-enable opcache.so. If the INI already has zend_extension=opcache then for the docker-php-ext-enable opcache.so call neither this:

php/docker-php-ext-enable

Lines 96 to 103 in 85abdb7

	if php -d 'display_errors=stderr' -r 'exit(extension_loaded("'"$ext"'") ? 0 : 1);'; then
	# this isn't perfect, but it's better than nothing
	# (for example, 'opcache.so' presents inside PHP as 'Zend OPcache', not 'opcache')
	echo >&2
	echo >&2 "warning: $ext ($module) is already loaded!"
	echo >&2
	continue
	fi

nor this:

php/docker-php-ext-enable

Line 114 in 85abdb7

if ! grep -qFx -e "$line" -e "$line.so" "$ini" 2>/dev/null; then

check trigger and as a result the the INI will be updated to:

zend_extension=opcache
zend_extension=opcache.so

[tianon]

My personal experience with opcache has been primarily negative, so this certainly causes me some pause, but that experience is admittedly really outdated now and this is probably sane (especially as it'll be the effective state in 8.5).

[tianon]

Gah, if without else isn't supported until jq 1.7 (https://github.com/jqlang/jq/releases/tag/jq-1.7), which we don't have on our primary infra (Debian-based, thus still jq 1.6). I've fixed it in a follow-up commit, but that's something we'll need to be aware of and watching for now (or will have to update CI across all our repos to deal with somehow). 😞

(If only GHA let us provide our own VM images without having to manage the VMs ourselves too 😭)

[AlexWinder]

Since this has been updated we've found that we need to disable OpCache within our Dockerfile to avoid some addition/division failures:

• Float addition/division issues #1588
• Float addition/division issues php/php-src#18947

[Girgias]

Since this has been updated we've found that we need to disable OpCache within our Dockerfile to avoid some addition/division failures:

* [Float addition/division issues #1588](https://github.com/docker-library/php/issues/1588)

* [Float addition/division issues php/php-src#18947](https://github.com/php/php-src/issues/18947)

As said on the php-src report, I doubt this is a general opcache issue but a JIT issue.

[tianon]

As noted in #1589 (comment), I think #1589 (comment) makes me think we probably merged this a bit prematurely (we should've waited until it was at least merged/enabled in upstream's development branch), but it is what it is at this point and we're probably better off just riding it through now to avoid too much churn (just recording this here for posterity / to make it easier to find).

[TimWolla]

@tianon Yeah, I had seen the comment over in the other PR and agree that the process was not ideal. Given that the RFC already had a working PoC implementation, I had anticipated it being merged more quickly.

It will probably happen for Alpha 3, php/php-src#18939 - the main part of the implementation is now already reviewed, but due to a vacation it will likely be merged after Alpha 2.