heroku-buildpack-php: Unable to install ext-mbstring

Hi, I’m currently maintaining a laravel 8 app on heroku and after an update today, i keep getting this error:

Call to undefined function Illuminate\Support\mb_strimwidth()

After diagnosing said problem, i found that adding ext-mbstring to composer.json would solve my issue. After doing that (composer update, git commit, etc.), checking the build log, heroku seems to fail to detect ext-mbstring and properly install it:

-----> Building on the Heroku-20 stack
-----> Using buildpack: heroku/php
-----> PHP app detected
-----> Bootstrapping...
-----> Preparing platform package installation...
-----> Installing platform packages...
       - php (8.1.2)
       - ext-gd (bundled with php)
       - apache (2.4.52)
       - composer (2.2.5)
       - nginx (1.20.2)
       - ext-exif (bundled with php)
-----> Installing dependencies...

This was not an issue before, as I can see ext-mbstring being installed on previous build logs:

-----> PHP app detected
-----> Bootstrapping...
-----> Preparing platform package installation...
-----> Installing platform packages...
       - php (8.1.2)
       - apache (2.4.52)
       - composer (2.2.5)
       - nginx (1.20.2)
       - ext-exif (bundled with php)
       - ext-gd (bundled with php)
       - ext-mbstring (bundled with php)

I’m at a loss as why this is happening now.

About this issue

Original URL
State: closed
Created 2 years ago
Reactions: 6
Comments: 15 (6 by maintainers)

Most upvoted comments

Fixed and released (#541) to the official stable buildpack channel.

@EvilasioAnisio, @derrickschoen, @OscarOzaine, @TireWizardBrandon, @obj63mc, @duffn, @alkemann, @jcart, @eithed, @legend6, @pedrommone and everyone else, you can now revert your workarounds.

Thank you for your patience and enjoy your weekend!

dzuelke on Feb 11, 2022

Please bear in mind that symfony/polyfill-mbstring doesn’t contain all mbstring methods.

Per @dzuelke though, replacing it within composer.json:

"require": {
        "php": "^8.1",
        "ext-mbstring": "*",
        ...
},
"replace": {
        "symfony/polyfill-mbstring": "*"
},

correctly bundles mbstring

-----> Installing platform packages...
       - php (8.1.2)
       - ext-intl (bundled with php)
       - ext-mbstring (bundled with php)

eithed on Feb 11, 2022

Hi all!

Right now, this is intentional - Composer is, finally, resolving all dependencies correctly into a minimal set for platform installs on Heroku, and since symfony/polyfill-mbstring is present and declaring a provide for ext-mbstring, this results in the “native” ext-mbstring not being installed.

There is work in flight to attempt installations for all provided extensions after the main install concludes; it’ll land very soon, but no promises that this will still happen this week.

In the meantime, as @OscarOzaine said, the workaround is to either:

require package symfony/polyfill-mbstring version ~1.23.1, or
declare package symfony/polyfill-mbstring as replaced (version *) in the root of your composer.json.

This issue will update once a fix has landed.

Thanks for your patience!

dzuelke on Feb 10, 2022