Expose installed PHP version as environment variable

[ruudk]

Describe the feature
It would be really helpful if the selected & installed php version would be exposed as an environment variable. This can then be used to construct caching keys.

Version
2.11.0

Underlying issue
I use the following YAML config to install PHP:

env:
      PHP_VERSION: 8
jobs:
# ...
        steps:
# ...
            -   name: Setup PHP
                uses: shivammathur/setup-php@2.11.0
                with:
                    php-version: ${{ env.PHP_VERSION }}
            -   name: Cache cache directory for phpstan/phpstan
                uses: actions/cache@v2.1.6
                with:
                    path: var/phpstan
                    key: ${{ runner.os }}-php-${{ env.PHP_VERSION }}-phpstan-${{ hashFiles('composer.json', 'composer.lock', 'phpstan.neon', 'phpstan-baseline.neon') }}-
                    restore-keys: ${{ runner.os }}-php-${{ env.PHP_VERSION }}-phpstan-

The action automatically installs the latest version when specifying 8 as input version. This is great.

==> Setup PHP
✓ PHP Found PHP 8.0.7

But now my cache key is always bound to 8 instead of the actual version.

Describe alternatives
Of course, I could run php -v command and export the version to the env var myself to solve this.

But I do believe more people will encounter this and that it would be great if the action would support it.

Are you willing to submit a PR?
If you can point me to where to apply this I would.

[shivammathur]

For using the semver PHP version in actions/cache keys, you will need steps outputs from setup-php.
https://github.com/actions/toolkit/blob/main/docs/commands.md#set-outputs
But using semver would clear the cache for each new PHP patch version, is that the intended consequence? If yes, I will add this in the next release.

On a side note instead of 8, you should specify '8.0' (with quotes) for PHP 8.0 or latest if you always want the latest stable version.
https://github.com/shivammathur/setup-php#php-version-required

[ruudk]

But using semver would clear the cache for each new PHP patch version, is that the intended consequence? If yes, I will add this in the next release.

That's my intent indeed. When a major, minor or patch version of PHP is released, miss the cache and run without cache.

[shivammathur]

@ruudk
Added in 2.12.0
https://github.com/shivammathur/setup-php#php-version

- name: Setup PHP
  id: setup-php
  uses: shivammathur/setup-php@v2
  with:
    php-version: '7.4'

- name: Print PHP version
  run: echo ${{ steps.setup-php.outputs.php-version }}