Plugins: Make more plugin-related functions available early on.

This is a follow-up to [59461], which moved `get_plugin_data()` from `wp-admin/includes/plugin.php` to `wp-includes/functions.php` so it's available during the plugin loading process.

Related functions like `is_plugin_active()` are often used together and should therefore be moved as well, to improve backward compatibility for plugins which load `wp-admin/includes/plugin.php` only conditionally.

Props johnbillion, dd32, swissspidy.
See #62244.

git-svn-id: https://develop.svn.wordpress.org/trunk@59479 602fd350-edb4-49c9-b593-d223f7449a82

Author: swissspidy

src/wp-admin/includes/plugin.php

@@ -304,97 +304,6 @@ function _get_dropins() {
 	return $dropins;
 }
 
-/**
- * Determines whether a plugin is active.
- *
- * Only plugins installed in the plugins/ folder can be active.
- *
- * Plugins in the mu-plugins/ folder can't be "activated," so this function will
- * return false for those plugins.
- *
- * For more information on this and similar theme functions, check out
- * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
- * Conditional Tags} article in the Theme Developer Handbook.
- *
- * @since 2.5.0
- *
- * @param string $plugin Path to the plugin file relative to the plugins directory.
- * @return bool True, if in the active plugins list. False, not in the list.
- */
-function is_plugin_active( $plugin ) {
-	return in_array( $plugin, (array) get_option( 'active_plugins', array() ), true ) || is_plugin_active_for_network( $plugin );
-}
-
-/**
- * Determines whether the plugin is inactive.
- *
- * Reverse of is_plugin_active(). Used as a callback.
- *
- * For more information on this and similar theme functions, check out
- * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
- * Conditional Tags} article in the Theme Developer Handbook.
- *
- * @since 3.1.0
- *
- * @see is_plugin_active()
- *
- * @param string $plugin Path to the plugin file relative to the plugins directory.
- * @return bool True if inactive. False if active.
- */
-function is_plugin_inactive( $plugin ) {
-	return ! is_plugin_active( $plugin );
-}
-
-/**
- * Determines whether the plugin is active for the entire network.
- *
- * Only plugins installed in the plugins/ folder can be active.
- *
- * Plugins in the mu-plugins/ folder can't be "activated," so this function will
- * return false for those plugins.
- *
- * For more information on this and similar theme functions, check out
- * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
- * Conditional Tags} article in the Theme Developer Handbook.
- *
- * @since 3.0.0
- *
- * @param string $plugin Path to the plugin file relative to the plugins directory.
- * @return bool True if active for the network, otherwise false.
- */
-function is_plugin_active_for_network( $plugin ) {
-	if ( ! is_multisite() ) {
-		return false;
-	}
-
-	$plugins = get_site_option( 'active_sitewide_plugins' );
-	if ( isset( $plugins[ $plugin ] ) ) {
-		return true;
-	}
-
-	return false;
-}
-
-/**
- * Checks for "Network: true" in the plugin header to see if this should
- * be activated only as a network wide plugin. The plugin would also work
- * when Multisite is not enabled.
- *
- * Checks for "Site Wide Only: true" for backward compatibility.
- *
- * @since 3.0.0
- *
- * @param string $plugin Path to the plugin file relative to the plugins directory.
- * @return bool True if plugin is network only, false otherwise.
- */
-function is_network_only_plugin( $plugin ) {
-	$plugin_data = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin );
-	if ( $plugin_data ) {
-		return $plugin_data['Network'];
-	}
-	return false;
-}
-
 /**
  * Attempts activation of plugin in a "sandbox" and redirects on success.
  *

src/wp-includes/functions.php

@@ -7145,6 +7145,97 @@ function _get_plugin_data_markup_translate( $plugin_file, $plugin_data, $markup
 	return $plugin_data;
 }
 
+/**
+ * Determines whether a plugin is active.
+ *
+ * Only plugins installed in the plugins/ folder can be active.
+ *
+ * Plugins in the mu-plugins/ folder can't be "activated," so this function will
+ * return false for those plugins.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 2.5.0
+ *
+ * @param string $plugin Path to the plugin file relative to the plugins directory.
+ * @return bool True, if in the active plugins list. False, not in the list.
+ */
+function is_plugin_active( $plugin ) {
+	return in_array( $plugin, (array) get_option( 'active_plugins', array() ), true ) || is_plugin_active_for_network( $plugin );
+}
+
+/**
+ * Determines whether the plugin is inactive.
+ *
+ * Reverse of is_plugin_active(). Used as a callback.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 3.1.0
+ *
+ * @see is_plugin_active()
+ *
+ * @param string $plugin Path to the plugin file relative to the plugins directory.
+ * @return bool True if inactive. False if active.
+ */
+function is_plugin_inactive( $plugin ) {
+	return ! is_plugin_active( $plugin );
+}
+
+/**
+ * Determines whether the plugin is active for the entire network.
+ *
+ * Only plugins installed in the plugins/ folder can be active.
+ *
+ * Plugins in the mu-plugins/ folder can't be "activated," so this function will
+ * return false for those plugins.
+ *
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
+ * Conditional Tags} article in the Theme Developer Handbook.
+ *
+ * @since 3.0.0
+ *
+ * @param string $plugin Path to the plugin file relative to the plugins directory.
+ * @return bool True if active for the network, otherwise false.
+ */
+function is_plugin_active_for_network( $plugin ) {
+	if ( ! is_multisite() ) {
+		return false;
+	}
+
+	$plugins = get_site_option( 'active_sitewide_plugins' );
+	if ( isset( $plugins[ $plugin ] ) ) {
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * Checks for "Network: true" in the plugin header to see if this should
+ * be activated only as a network wide plugin. The plugin would also work
+ * when Multisite is not enabled.
+ *
+ * Checks for "Site Wide Only: true" for backward compatibility.
+ *
+ * @since 3.0.0
+ *
+ * @param string $plugin Path to the plugin file relative to the plugins directory.
+ * @return bool True if plugin is network only, false otherwise.
+ */
+function is_network_only_plugin( $plugin ) {
+	$plugin_data = get_plugin_data( WP_PLUGIN_DIR . '/' . $plugin );
+	if ( $plugin_data ) {
+		return $plugin_data['Network'];
+	}
+	return false;
+}
+
 /**
  * Returns true.
  *