@wordpress/env: Allow configuration of wp-config.php constants in .wp-env.json

[WraithKenny]

No description provided.

[epiqueras]

cc @noisysocks

[noisysocks]

Yep, let's do it.

Some notes regarding implementation:

• It must be possible to configure the WordPress debug constants, namely: WP_DEBUG, WP_DEBUG_LOG, WP_DEBUG_DISPLAY, and SCRIPT_DEBUG. WP_DEBUG and SCRIPT_DEBUG should be enabled by default.

• Constants should be configurable using .wp-env.json only and not e.g. using an environment variable. This is because WordPress constants are generally a per project setting. See wp-env: Add custom port numbers to .wp-env.json #20158 (comment). Also, using JSON for this means that we can avoid issues where e.g. a constant must be true instead of "true".

• The local wp-config.php file, if it exists, should be updated when wp-env start is ran so as to ensure that the config in wp-config.php matches the config specified in .wp-env.json. Only the constants specified in .wp-env.json should be modified: that is, any other code that is in wp-config.php should not be touched. To do this we will need to roll our own wp-config.php generation using wp config create and wp config set. Right now we are relying on the wordpress Docker image to generate the wp-config.php but this is not flexible enough to handle updates to arbitrary constants—it can only update database constants.

• Because wp-env is a tool specifically for WordPress and config in WordPress parlance has a very specific meaning, I think we can get away with using "config" as the key in .wp-env.json.

  {
  	"themes": [
  		"../path/to/theme/dir"
  	],
  	"plugins": [
  		"../path/to/plugin/dir"
  	],
  	"config": {
  		"WP_DEBUG": true,
  		"SCRIPT_DEBUG": true,
  		"SAVEQUERIES": true,
  		"JETPACK_DEV_DEBUG": true
  	}
  }

[epiqueras]

Only the constants specified in .wp-env.json should be modified: that is, any other code that is in wp-config.php should not be touched.

Why is that necessary?

[noisysocks]

If you're using a local install (e.g. "core": "~/path/to/wordpress-develop/build") you may prefer to add code or constants to the wp-config.php manually. wp-env shouldn't blow those changes away if it can help it. At any rate, wp config set handles this correctly so we get it for free.

[epiqueras]

What about the same constants being already defined in wp-config.php, should we overwrite them?

I guess we should.

[noisysocks]

Yes, I think so.