Support separate web root and WordPress core directory

[adamziel]

Summary

On WP Cloud sites, the web root and WordPress core directory are separate paths:

• Web root: /srv/htdocs (contains wp-content/)
• WP root: /srv/htdocs/__wp__/ (contains wp-load.php, wp-includes/, wp-admin/)

The blueprint runner previously assumed these were always the same directory. All subprocess scripts used DOCROOT to find both wp-content/ and wp-load.php, which breaks on split layouts.

This PR introduces a WP_CORE_DIR environment variable that points to where WordPress core files live, independent of DOCROOT (the web root). On standard installs they're identical; on WP Cloud they differ.

The ExistingSiteResolver auto-detects the core directory by scanning immediate subdirectories for wp-load.php, so existing blueprints work without changes. A --wp-core-path CLI flag is also available for explicit configuration.

Test plan

• New unit tests for detect_wordpress_core_dir() (standard layout, __wp__/ subdirectory, custom subdirectory, no WP found, deeply nested, nonexistent path)
• New unit tests for RunnerConfiguration (default fallback, explicit override, reset to null)
• Verify existing CI tests still pass (the change is backwards-compatible since WP_CORE_DIR defaults to DOCROOT)
• Test on a WP Cloud site with split web/core roots

[mdbitz]

I circled back to this doing some testing and am still unable to get the blueprint runner to execute on the WP Cloud environment.

To test I checked out this project locally and built the phar that I uploaded to my test site. I tested using the following command and blueprint.json file.

php blueprints.phar exec blueprints.json --mode apply-to-existing-site --site-url "https://anonymous-hedgehog.jurassic.ninja" --site-path "/srv/htdocs" --db-user 151688099 --db-pass "REDACTED" --db-name 151688099 --wp-core-path=/srv/htdocs/__wp__/


[>                                                 ] 0.0% -   Site URL:  https://anonymous-hedgehog.Error: Failed to load WordPress installation: The target site exists but WordPress is not properly installed or configured

The built phar has the new code as it accepts wp-core-path as a known option.

blueprints.json testing with.

{
  "$schema": "https://playground.wordpress.net/blueprint-schema.json",
  "steps": [
    {
      "step": "installPlugin",
      "pluginData": {
        "resource": "wordpress.org/plugins",
        "slug": "gutenberg"
      },
      "options": {
        "activate": true
      }
    }
  ]
}

I was looking over this change in more detail and on the WP Cloud environments we have a symlink at /srv/htdocs/wp-load.php that points to /srv/htdocs/__wp__/wp-load.php and so supplying the core path doesn't change the execution.

The issue is stemming from the following test executed in $runtime->eval_php_code_in_subprocess of class-existingsiteresolver.php when i pull the code out directly into a test.php file it runs without issue.

<?php
				require_once( "/srv/htdocs/" . "/wp-load.php");
				$is_installed = function_exists("is_blog_installed") && is_blog_installed() ? "true" : "false";
				echo "WordPress is installed: " . $is_installed;

[adamziel]

@mdbitz thank you for reviewing! I'll revisit this and ping you