AI: Catch exceptions in WP_AI_Client_Prompt_Builder::__construct().

Exceptions were already caught and transformed into `WP_Error` objects in all instance methods of `WP_AI_Client_Prompt_Builder`, but not in the constructor. This meant that if an exception was thrown during construction, it would not be caught and would cause a fatal error instead of returning a `WP_Error` object.

Props gziolo.
See #64591.


git-svn-id: https://develop.svn.wordpress.org/trunk@61787 602fd350-edb4-49c9-b593-d223f7449a82

Author: felixarntz

src/wp-includes/ai-client/class-wp-ai-client-prompt-builder.php

@@ -165,7 +165,18 @@ class WP_AI_Client_Prompt_Builder {
 	 *                                                                                                    conversations. Default null.
 	 */
 	public function __construct( ProviderRegistry $registry, $prompt = null ) {
-		$this->builder = new PromptBuilder( $registry, $prompt );
+		try {
+			$this->builder = new PromptBuilder( $registry, $prompt );
+		} catch ( Exception $e ) {
+			$this->builder = new PromptBuilder( $registry );
+			$this->error   = new WP_Error(
+				'prompt_builder_error',
+				$e->getMessage(),
+				array(
+					'exception_class' => get_class( $e ),
+				)
+			);
+		}
 
 		/**
 		 * Filters the default request timeout in seconds for AI Client HTTP requests.

tests/phpunit/tests/ai-client/wpAiClientPromptBuilder.php

@@ -1347,22 +1347,15 @@ public function test_validate_messages_non_user_last_returns_wp_error() {
 	/**
 	 * Tests parseMessage with empty string returns WP_Error on termination.
 	 *
-	 * The SDK constructor throws immediately for empty strings, so the exception
-	 * is caught in the constructor and stored.
-	 *
 	 * @ticket 64591
 	 */
 	public function test_parse_message_empty_string_returns_wp_error() {
-		// The empty string exception is thrown by the SDK's PromptBuilder constructor,
-		// which happens before our __call() error handling. We must catch it manually.
-		try {
-			$builder = new WP_AI_Client_Prompt_Builder( $this->registry, '   ' );
-			// If we get here, the SDK didn't throw. Test would need adjusting.
-			$result = $builder->generate_result();
-			$this->assertWPError( $result );
-		} catch ( InvalidArgumentException $e ) {
-			$this->assertStringContainsString( 'Cannot create a message from an empty string', $e->getMessage() );
-		}
+		$builder = new WP_AI_Client_Prompt_Builder( $this->registry, '   ' );
+		$result  = $builder->generate_result();
+
+		$this->assertWPError( $result );
+		$this->assertSame( 'prompt_builder_error', $result->get_error_code() );
+		$this->assertStringContainsString( 'Cannot create a message from an empty string', $result->get_error_message() );
 	}
 
 	/**
@@ -1371,13 +1364,12 @@ public function test_parse_message_empty_string_returns_wp_error() {
 	 * @ticket 64591
 	 */
 	public function test_parse_message_empty_array_returns_wp_error() {
-		try {
-			$builder = new WP_AI_Client_Prompt_Builder( $this->registry, array() );
-			$result  = $builder->generate_result();
-			$this->assertWPError( $result );
-		} catch ( InvalidArgumentException $e ) {
-			$this->assertStringContainsString( 'Cannot create a message from an empty array', $e->getMessage() );
-		}
+		$builder = new WP_AI_Client_Prompt_Builder( $this->registry, array() );
+		$result  = $builder->generate_result();
+
+		$this->assertWPError( $result );
+		$this->assertSame( 'prompt_builder_error', $result->get_error_code() );
+		$this->assertStringContainsString( 'Cannot create a message from an empty array', $result->get_error_message() );
 	}
 
 	/**
@@ -1386,13 +1378,31 @@ public function test_parse_message_empty_array_returns_wp_error() {
 	 * @ticket 64591
 	 */
 	public function test_parse_message_invalid_type_returns_wp_error() {
-		try {
-			$builder = new WP_AI_Client_Prompt_Builder( $this->registry, 123 );
-			$result  = $builder->generate_result();
-			$this->assertWPError( $result );
-		} catch ( InvalidArgumentException $e ) {
-			$this->assertStringContainsString( 'Input must be a string, MessagePart, MessagePartArrayShape', $e->getMessage() );
-		}
+		$builder = new WP_AI_Client_Prompt_Builder( $this->registry, 123 );
+		$result  = $builder->generate_result();
+
+		$this->assertWPError( $result );
+		$this->assertSame( 'prompt_builder_error', $result->get_error_code() );
+		$this->assertStringContainsString( 'Input must be a string, MessagePart, MessagePartArrayShape', $result->get_error_message() );
+	}
+
+	/**
+	 * Tests that wp_ai_client_prompt() with an empty string does not throw.
+	 *
+	 * Constructor exceptions are caught and surfaced as WP_Error from
+	 * generating methods, consistent with the __call() wrapping behavior.
+	 *
+	 * @ticket 64591
+	 */
+	public function test_wp_ai_client_prompt_empty_string_returns_wp_error() {
+		$builder = wp_ai_client_prompt( '   ' );
+
+		$this->assertInstanceOf( WP_AI_Client_Prompt_Builder::class, $builder );
+
+		$result = $builder->generate_text();
+
+		$this->assertWPError( $result );
+		$this->assertSame( 'prompt_builder_error', $result->get_error_code() );
 	}
 
 	/**