Fix misleading success message when version check API fails

features/core-check-update.feature

@@ -70,3 +70,19 @@ Feature: Check for more recent versions
       """
       ---
       """
+
+  Scenario: Check update shows warning when version check API fails
+    Given a WP install
+    And that HTTP requests to https://api.wordpress.org/core/version-check/1.7/ will respond with:
+      """
+      HTTP/1.1 500 Internal Server Error
+      Content-Type: text/plain
+
+      <Error body>
+      """
+
+    When I try `wp core check-update --force-check`
+    Then STDERR should contain:
+      """
+      Warning: Failed to check for updates
+      """

src/Core_Command.php

@@ -31,6 +31,13 @@
  */
 class Core_Command extends WP_CLI_Command {
 
+	/**
+	 * Stores HTTP API errors encountered during version check.
+	 *
+	 * @var \WP_Error|null
+	 */
+	private $version_check_error = null;
+
 	/**
 	 * Checks for WordPress updates via Version Check API.
 	 *
@@ -92,6 +99,14 @@ public function check_update( $args, $assoc_args ) {
 				[ 'version', 'update_type', 'package_url' ]
 			);
 			$formatter->display_items( $updates );
+		} elseif ( $this->version_check_error ) {
+			// If there was an HTTP error during version check, show a warning
+			WP_CLI::warning(
+				sprintf(
+					'Failed to check for updates: %s',
+					$this->version_check_error->get_error_message()
+				)
+			);
 		} else {
 			WP_CLI::success( 'WordPress is at the latest version.' );
 		}
@@ -1453,7 +1468,25 @@ private function get_download_url( $version, $locale = 'en_US', $file_type = 'zi
 	 */
 	private function get_updates( $assoc_args ) {
 		$force_check = Utils\get_flag_value( $assoc_args, 'force-check' );
-		wp_version_check( [], $force_check );
+
+		// Reset error tracking
+		$this->version_check_error = null;
+
+		// Hook into pre_http_request with max priority to capture errors during version check
+		// This is necessary because tests and plugins may use pre_http_request to mock responses
+		add_filter( 'pre_http_request', [ $this, 'capture_version_check_error' ], PHP_INT_MAX, 3 );
+
+		// Also hook into http_api_debug to capture errors from real HTTP requests
+		// This fires when pre_http_request doesn't short-circuit the request
+		add_action( 'http_api_debug', [ $this, 'capture_version_check_error_from_response' ], 10, 5 );
+
+		try {
+			wp_version_check( [], $force_check );
+		} finally {
+			// Ensure the hooks are always removed, even if wp_version_check() throws an exception
+			remove_filter( 'pre_http_request', [ $this, 'capture_version_check_error' ], PHP_INT_MAX );
+			remove_action( 'http_api_debug', [ $this, 'capture_version_check_error_from_response' ], 10 );
+		}
 
 		/**
 		 * @var object{updates: array<object{version: string, locale: string, packages: object{partial?: string, full: string}}>}|false $from_api
@@ -1510,6 +1543,81 @@ private function get_updates( $assoc_args ) {
 		return array_values( $updates );
 	}
 
+	/**
+	 * Sets or clears the version check error property based on an HTTP response.
+	 *
+	 * @param mixed $response The HTTP response (WP_Error, array, or other).
+	 */
+	private function set_version_check_error( $response ) {
+		if ( is_wp_error( $response ) ) {
+			$this->version_check_error = $response;
+		} elseif ( is_array( $response ) && isset( $response['response']['code'] ) && $response['response']['code'] >= 400 ) {
+			// HTTP error status code (4xx or 5xx) - convert to WP_Error for consistency
+			$this->version_check_error = new \WP_Error(
+				'http_request_failed',
+				sprintf(
+					'HTTP request failed with status %d: %s',
+					$response['response']['code'],
+					isset( $response['response']['message'] ) ? $response['response']['message'] : 'Unknown error'
+				)
+			);
+		} else {
+			// Clear any previous error if we got a successful response.
+			$this->version_check_error = null;
+		}
+	}
+
+	/**
+	 * Handles the pre_http_request filter to capture HTTP errors during version check.
+	 *
+	 * This method signature matches the pre_http_request filter signature.
+	 * Uses PHP_INT_MAX priority to run after test mocking and plugin modifications.
+	 *
+	 * @param false|array|WP_Error $response A preemptive return value of an HTTP request.
+	 * @param array                $args     HTTP request arguments.
+	 * @param string               $url      The request URL.
+	 * @return false|array|WP_Error The response, unmodified.
+	 */
+	public function capture_version_check_error( $response, $args, $url ) {
+		if ( false === strpos( $url, 'api.wordpress.org/core/version-check' ) ) {
+			return $response;
+		}
+
+		// A `false` response means the request is not being preempted.
+		// In this case, we don't want to change the error status, as the subsequent
+		// `http_api_debug` hook will handle the actual response.
+		if ( false !== $response ) {
+			$this->set_version_check_error( $response );
+		}
+
+		return $response;
+	}
+
+	/**
+	 * Handles the http_api_debug action to capture HTTP errors from real requests.
+	 *
+	 * This fires when pre_http_request doesn't short-circuit the request.
+	 * Uses the http_api_debug action hook signature.
+	 *
+	 * @param array|WP_Error $response HTTP response or WP_Error object.
+	 * @param string         $context  Context of the HTTP request.
+	 * @param string         $_class   HTTP transport class name (unused).
+	 * @param array          $_args    HTTP request arguments (unused).
+	 * @param string         $url      URL being requested.
+	 */
+	public function capture_version_check_error_from_response( $response, $context, $_class, $_args, $url ) {
+		if ( false === strpos( $url, 'api.wordpress.org/core/version-check' ) ) {
+			return;
+		}
+
+		// Only capture on response, not pre_response
+		if ( 'response' !== $context ) {
+			return;
+		}
+
+		$this->set_version_check_error( $response );
+	}
+
 	/**
 	 * Clean up extra files.
 	 *