Validate plugin/theme names using filter_item_list

Use filter_item_list() to validate plugin and theme names before checking for updates. This ensures that invalid names produce errors instead of silent success messages, consistent with other commands like update and auto-updates.

Also added test scenarios to verify error handling for invalid plugin/theme names.

Co-authored-by: swissspidy <841956+swissspidy@users.noreply.github.com>

Author: Copilot

features/plugin-check-update.feature

@@ -90,3 +90,13 @@ Feature: Check for plugin updates
     Then STDOUT should be a table containing rows:
       | name               | version |
       | wordpress-importer | 0.5     |
+
+  Scenario: Check for invalid plugin should error
+    Given a WP install
+
+    When I try `wp plugin check-update invalid-plugin-name`
+    Then the return code should be 1
+    And STDERR should contain:
+      """
+      Error:
+      """

features/theme-check-update.feature

@@ -88,3 +88,13 @@ Feature: Check for theme updates
     Then STDOUT should be a table containing rows:
       | name           | version |
       | twentyfourteen | 1.0     |
+
+  Scenario: Check for invalid theme should error
+    Given a WP install
+
+    When I try `wp theme check-update invalid-theme-name`
+    Then the return code should be 1
+    And STDERR should contain:
+      """
+      Error:
+      """

src/Plugin_Command.php

@@ -174,6 +174,11 @@ public function check_update( $args, $assoc_args ) {
 
 		$items = $this->get_item_list();
 
+		// If specific plugins requested, validate and filter to those
+		if ( ! $all ) {
+			$items = $this->filter_item_list( $items, $args );
+		}
+
 		// Filter to only plugins with available updates
 		$items_with_updates = array_filter(
 			$items,
@@ -182,16 +187,6 @@ function ( $item ) {
 			}
 		);
 
-		// If specific plugins requested, filter to those
-		if ( ! empty( $args ) ) {
-			$items_with_updates = array_filter(
-				$items_with_updates,
-				function ( $item ) use ( $args ) {
-					return in_array( $item['name'], $args, true );
-				}
-			);
-		}
-
 		if ( empty( $items_with_updates ) ) {
 			WP_CLI::success( 'All plugins are up to date.' );
 			return;

src/Theme_Command.php

@@ -168,11 +168,16 @@ public function check_update( $args, $assoc_args ) {
 
 		$items = $this->get_item_list();
 
+		// If specific themes requested, validate and filter to those
+		if ( ! $all ) {
+			$items = $this->filter_item_list( $items, $args );
+		}
+
 		// Filter to only themes with available updates
 		$items_with_updates = array_filter(
 			$items,
-			function ( $item ) use ( $args ) {
-				return in_array( $item['name'], $args, true ) && 'available' === $item['update'];
+			function ( $item ) {
+				return 'available' === $item['update'];
 			}
 		);