Why the php-actions/composer action fails despite having installed pdo_mysql

Question

I have this actions that allows me to run unit tests upon PR:

name: on-pr-unittest

on:
  pull_request:
    branches:
      - dev

jobs:
  run_unit_test:
    runs-on: ubuntu-latest
    services:
      mariadb:
        image: mariadb:latest
        ports:
          - 33306:3306
        env:
          MYSQL_USER: php_usr
          MYSQL_PASSWORD: php_apsswd
          MYSQL_DATABASE: test_php_app
          MYSQL_ROOT_PASSWORD: password

    steps:
      - name: Check Out Repo
        uses: actions/checkout@v4

      - name: Remove Default Mysql and install nessesary tools to ping db connection
        env:
          DEBIAN_FRONTEND: noninteractive
        run: |
          sudo service mysql stop
          sudo apt-get update && sudo apt-get purge -y mysql* && sudo apt-get install -y mariadb-client-10.6 netcat

      # I do not want to modify the .env.testing therefore I spin my own host
      - name: Add hosts to /etc/hosts
        run: |
          sudo echo "127.0.0.1 mariadb" | sudo tee -a /etc/hosts

      - name: Test Connect Into DB
        run: |
          docker ps &&
          nc -vz mariadb 33306 &&
          mysql -h localhost -u php_usr -pphp_apsswd test_php_app -P 33306 -e "select DATABASE();"

      - name: Setup PHP with PECL extension
        uses: shivammathur/setup-php@v2
        with:
          php-version: '8.2'
          extensions: bcmath, ctype, curl, dom, fileinfo, filter, hash, mbstring, openssl, pcre, pdo, pdo_mysql, tokenizer, libxml

      - name: Install dependencies
        uses: php-actions/composer@v6

      - name: PHPUnit tests
        run: |
          sed -i "s/DB_PORT=.*/DB_PORT=33306/" .env.testing &&
          ./vendor/bin/phpunit

But upon ruuning the step php-actions/composer I get this error:

Run php-actions/composer@v6
Run set -e
  
Installing dependencies from lock file (including require-dev)
Verifying lock file contents can be installed on current platform.
Your lock file does not contain a compatible set of packages. Please run composer update.
  Problem 1
    - Root composer.json requires PHP extension ext-pdo_mysql * but it is missing from your system. Install or enable PHP's pdo_mysql extension.
To enable extensions, verify that they are enabled in your .ini files:
    - /usr/local/etc/php/conf.d/docker-php-ext-sodium.ini
You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode.
Alternatively, you can run Composer with `--ignore-platform-req=ext-pdo_mysql` to temporarily ignore these required extensions.
Error: Your lock file does not contain a compatible set of packages. Please run composer update.

  Problem 1
    - Root composer.json requires PHP extension ext-pdo_mysql * but it is missing from your system. Install or enable PHP's pdo_mysql extension.

To enable extensions, verify that they are enabled in your .ini files:
    - /usr/local/etc/php/conf.d/docker-php-ext-sodium.ini
You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode.
Alternatively, you can run Composer with `--ignore-platform-req=ext-pdo_mysql` to temporarily ignore these required extensions.

Despite installing the pdo_mysql extetion on a previous step:

      - name: Setup PHP with PECL extension
        uses: shivammathur/setup-php@v2
        with:
          php-version: '8.3'
          extensions: bcmath, ctype, curl, dom, fileinfo,sodium, filter, hash, mbstring, openssl, pcre, pdo, pdo_mysql, tokenizer, libxml

Why this happens and how I can fix it?

Answer 1

TLDR A way to fix the issue is to append the php_extensions parameter:

      - name: Install dependencies
        uses: php-actions/composer@v6
        with:
          php_extensions: pdo_mysql

Resulting to this config:

name: on-pr-unittest

on:
  push:
  pull_request:
    branches:
      - dev

jobs:
  run_unit_test:
    runs-on: ubuntu-latest
    services:
      mariadb:
        image: mariadb:latest
        ports:
          - 33306:3306
        env:
          MYSQL_USER: php_usr
          MYSQL_PASSWORD: php_apsswd
          MYSQL_DATABASE: test_php_app
          MYSQL_ROOT_PASSWORD: password

    steps:
      - name: Check Out Repo
        uses: actions/checkout@v4

      - name: Remove Default Mysql and install nessesary tools to ping db connection
        env:
          DEBIAN_FRONTEND: noninteractive
        run: |
          sudo service mysql stop
          sudo apt-get update && sudo apt-get purge -y mysql* && sudo apt-get install -y mariadb-client-10.6 netcat

      # I do not want to modify the .env.testing therefore I spin my own host
      - name: Add hosts to /etc/hosts
        run: |
          sudo echo "127.0.0.1 mariadb" | sudo tee -a /etc/hosts

      - name: Test Connect Into DB
        run: |
          docker ps &&
          nc -vz mariadb 33306 &&
          mysql -h localhost -u php_usr -pphp_apsswd test_php_app -P 33306 -e "select DATABASE();"

      - name: Setup PHP with PECL extension
        uses: shivammathur/setup-php@v2
        with:
          php-version: '8.3'
          extensions: bcmath, ctype, curl, dom, fileinfo, sodium, filter, hash, mbstring, openssl, pcre, pdo, pdo_mysql, tokenizer, libxml

      - name: Install dependencies
        uses: php-actions/composer@v6
        with:
          php_extensions: pdo_mysql

      - name: PHPUnit tests
        run: |
          sed -i 's/<env name="DB_PORT" value="3306" \/>/<env name="DB_PORT" value="33306" \/>/' phpunit.xml &&
          ./vendor/bin/phpunit

The reason why this happens is because the php-actions/composer runs its own php into a seperate container, thus needs to re-install any missing modules again.

An alternate approach is not to use iot at all and install it manually.