Upgrades: Allow upgrades to proceed when a soft failure occurs on package signatures.

In particular, this allows downgrading from WordPress 5.2 to 5.1.1, if sites wish to opt out of the beta.

Props dd32.
See #46615.


Built from https://develop.svn.wordpress.org/trunk@45046


git-svn-id: http://core.svn.wordpress.org/trunk@44855 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-core-upgrader.php

@@ -122,6 +122,25 @@ class Core_Upgrader extends WP_Upgrader {
 		}
 
 		$download = $this->download_package( $current->packages->$to_download );
+
+		// Allow for signature soft-fail.
+		// WARNING: This may be removed in the future.
+		if ( is_wp_error( $download ) && $download->get_error_data( 'softfail-filename' ) ) {
+			// Outout the failure error as a normal feedback, and not as an error:
+			apply_filters( 'update_feedback', $download->get_error_message() );
+
+			// Report this failure back to WordPress.org for debugging purposes.
+			wp_version_check(
+				array(
+					'signature_failure_code' => $download->get_error_code(),
+					'signature_failure_data' => $download->get_error_data(),
+				)
+			);
+
+			// Pretend this error didn't happen.
+			$download = $download->get_error_data( 'softfail-filename' );
+		}
+
 		if ( is_wp_error( $download ) ) {
 			WP_Upgrader::release_lock( 'core_updater' );
 			return $download;

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.2-alpha-45045';
+$wp_version = '5.2-alpha-45046';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.