Merge branch 'develop' into as-8871-ece-on-supported-product-types

.gitignore

@@ -68,6 +68,7 @@ contributors.md
 # Volumes mounted by Docker containers
 docker/data
 docker/wordpress
+docker/mu-plugins
 docker/logs
 
 # Local machine docker override

changelog/dev-add-docker-support-for-local-mu-plugins

@@ -0,0 +1,5 @@
+Significance: patch
+Type: dev
+Comment: Add support for mu-plugins.
+
+

docker-compose.yml

@@ -22,6 +22,7 @@ services:
       - default.env
     volumes:
       - ./docker/wordpress:/var/www/html/
+      - ./docker/mu-plugins:/var/www/html/wp-content/mu-plugins
       - ./docker/logs/apache2/:/var/log/apache2
       - .:/var/www/html/wp-content/plugins/woocommerce-payments
       - ./docker/wc-payments-php.ini:/usr/local/etc/php/conf.d/wc-payments-php.ini

docker/README.md

@@ -59,3 +59,17 @@ services:
 ```
 I used port `9003` as an example.
 To apply the change, restart your containers using `npm run down && npm run up`
+
+### Adding local helper scripts/hacks
+
+You can add local PHP scripts in the `docker/mu-plugins` directory since it's mounted as the `wp-content/mu-plugins` WordPress directory in your Docker container. These PHP scripts will be loaded automatically because they are treated as [WordPress must-use plugins](https://developer.wordpress.org/advanced-administration/plugins/mu-plugins/).
+
+**Note:** Please make sure that you try to think of these scripts as _temporary solutions/helpers_ and not as permanent code to be run constantly (unless you are sure that is what you want). 
+
+One _recommended way_ of working with your collection of helper scripts is to take advantage of the fact that _WordPress will not automatically load PHP files_ in subdirectories of `wp-content/mu-plugins` (as it does with regular plugins in `wp-content/plugins`).
+
+1. Create a new directory in `docker/mu-plugins` for your scripts, e.g. `docker/mu-plugins/local-helpers`. WordPress will not automatically load PHP files in subdirectories of `mu-plugins`, so you need to include them manually.
+2. Create a new PHP file in `docker/mu-plugins`,e.g. `docker/mu-plugins/0-local-helpers.php`.
+3. Add lines like `require_once __DIR__ . '/local-helpers/your-script.php';` to `docker/mu-plugins/0-local-helpers.php` to load your scripts.
+4. Comment/uncomment the `require_once` lines to load the scripts you need for your particular itch.
+5. Make sure you comment out any lines once you are finished with that itch to avoid unexpected/non-standard behavior on your local environment going forward - leftover helpers are not helpful!