Bootstrap/Load: Introduce `wp_get_environment_type()` to retrieve the current environment type.

The type can be set via the `WP_ENVIRONMENT_TYPE` global system variable, a constant of the same name, or the `wp_get_environment_type` filter.

Possible values include `development`, `stage`, `production'. If not set, the type defaults to `production`.

Props Clorith, krogsgard, joostdevalk, frank-klein, Maelacuna, nathanrice, grierson, jchristopher, davidvee, jackfungi, johnbillion, tabrisrp, knutsp, ev3rywh3re, Rastaban, danielbachhuber, pfefferle, audrasjb, SergeyBiryukov.
Fixes #33161.
Built from https://develop.svn.wordpress.org/trunk@47919


git-svn-id: http://core.svn.wordpress.org/trunk@47693 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/load.php

@@ -128,6 +128,75 @@ function wp_check_php_mysql_versions() {
 	}
 }
 
+/**
+ * Retrieves the current environment type.
+ *
+ * The type can be set via the `WP_ENVIRONMENT_TYPE` global system variable,
+ * a constant of the same name, or the {@see 'wp_get_environment_type'} filter.
+ *
+ * Possible values include 'development', 'stage', 'production'. If not set,
+ * the type defaults to 'production'.
+ *
+ * @since 5.5.0
+ *
+ * @return string The current environment type.
+ */
+function wp_get_environment_type() {
+	$approved_environments = array(
+		'development',
+		'stage',
+		'production',
+	);
+
+	/**
+	 * Filters the list of approved environment types.
+	 *
+	 * This filter runs before it can be used by plugins. It is designed for non-web runtimes.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param string $approved_environments The list of approved environment types. Possible values
+	 *                                      include 'development', 'stage', 'production'.
+	 */
+	$approved_environments = apply_filters( 'wp_approved_environment_types', $approved_environments );
+
+	$current_env = '';
+
+	// Check if a environment variable has been set for max flexibility, if `getenv` is available on the system.
+	if ( function_exists( 'getenv' ) ) {
+		$has_env = getenv( 'WP_ENVIRONMENT_TYPE' );
+		if ( false !== $has_env ) {
+			$current_env = $has_env;
+		}
+	}
+
+	// Fetch the environment from a constant, this overrides the global system variable.
+	if ( defined( 'WP_ENVIRONMENT_TYPE' ) ) {
+		$current_env = WP_ENVIRONMENT_TYPE;
+	}
+
+	/**
+	 * Filters the current environment type.
+	 *
+	 * This filter runs before it can be used by plugins. It is designed for
+	 * non-web runtimes. The value returned by this filter has a priority over both
+	 * the `WP_ENVIRONMENT_TYPE` system variable and a constant of the same name.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @param string $current_env The current environment type. Possible values
+	 *                            include 'development', 'stage', 'production'.
+	 */
+	$current_env = apply_filters( 'wp_get_environment_type', $current_env );
+
+	// Make sure the environment is an allowed one, and not accidentally set to an invalid value.
+	if ( ! in_array( $current_env, $approved_environments, true ) ) {
+		$current_env = 'production';
+	}
+
+	return $current_env;
+}
+
 /**
  * Don't load all of WordPress when handling a favicon.ico request.
  *

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-alpha-47915';
+$wp_version = '5.5-alpha-47919';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.