Detect IndieAuth via the INDIEAUTH_PLUGIN_VERSION constant

micropub.php

@@ -41,7 +41,7 @@
 // Compatibility Functions with Newer WordPress Versions.
 require_once MICROPUB_PLUGIN_DIR . 'includes/compat-functions.php';
 
-if ( \class_exists( \IndieAuth\IndieAuth::class ) ) {
+if ( \defined( 'INDIEAUTH_PLUGIN_VERSION' ) ) {
 	\add_action( 'plugins_loaded', array( Micropub::get_instance(), 'init' ) );
 } else {
 	\add_action( 'admin_notices', __NAMESPACE__ . '\indieauth_not_installed_notice' );

readme.md

@@ -73,6 +73,10 @@ These configuration options can be enabled by adding them to your wp-config.php:
 
 Project and support maintained on GitHub at [indieweb/wordpress-micropub](https://github.com/indieweb/wordpress-micropub).
 
+### Unreleased
+
+* Detect the IndieAuth plugin via the `INDIEAUTH_PLUGIN_VERSION` constant instead of a class check, which avoids coupling to IndieAuth's class names (indieweb/wordpress-indieauth#319) and requires IndieAuth 4.7.0 or later
+
 ### 2.5.1
 
 * Fix error responses for failed post inserts and updates, returning the proper HTTP status code instead of a success response

tests/phpunit/bootstrap.php

@@ -12,7 +12,8 @@
 	define( 'WP_TESTS_PHPUNIT_POLYFILLS_PATH', $_phpunit_polyfills_path );
 }
 
-require __DIR__ . '/includes/class-indieauth-plugin.php';
+// Simulate an active IndieAuth plugin (4.7.0+ defines this constant).
+define( 'INDIEAUTH_PLUGIN_VERSION', '4.7.0' );
 
 define( 'DIR_MEDIATESTDATA', __DIR__ . '/data' );