diff --git a/includes/api/ApiQueryImageInfo.php b/includes/api/ApiQueryImageInfo.php
index 626aef000d6..51b1e127e2d 100644
--- a/includes/api/ApiQueryImageInfo.php
+++ b/includes/api/ApiQueryImageInfo.php
@@ -196,7 +196,8 @@ class ApiQueryImageInfo extends ApiQueryBase {
 					$info['badfile'] = (bool)$this->badFileLookup->isBadFile( $title, $badFileContextTitle );
 				}
 
-				$fit = $result->addValue( [ 'query', 'pages' ], (int)$pageId, $info );
+				// Use ApiResult::IGNORE_CONFLICT_KEYS, the module is extended and the value can be set twice (T402438)
+				$fit = $result->addValue( [ 'query', 'pages' ], (int)$pageId, $info, ApiResult::IGNORE_CONFLICT_KEYS );
 				if ( !$fit ) {
 					if ( count( $pageIds[NS_FILE] ) == 1 ) {
 						// The user is screwed. imageinfo can't be solely
diff --git a/includes/api/ApiResult.php b/includes/api/ApiResult.php
index ff1c4b4cb62..7b85d12f594 100644
--- a/includes/api/ApiResult.php
+++ b/includes/api/ApiResult.php
@@ -73,6 +73,13 @@ class ApiResult implements ApiSerializable {
 	 */
 	public const NO_VALIDATE = self::NO_SIZE_CHECK | 8;
 
+	/**
+	 * For addValue(), setValue() and similar functions, do allow override
+	 * of conflicting keys.
+	 * @since 1.45 (also backported to 1.43.6, 1.44.3)
+	 */
+	public const IGNORE_CONFLICT_KEYS = 16;
+
 	/**
 	 * Key for the 'indexed tag name' metadata item. Value is string.
 	 * @since 1.25
@@ -309,7 +316,7 @@ class ApiResult implements ApiSerializable {
 			}
 		} elseif ( is_array( $arr[$name] ) && is_array( $value ) ) {
 			$conflicts = array_intersect_key( $arr[$name], $value );
-			if ( !$conflicts ) {
+			if ( !$conflicts || ( $flags & self::IGNORE_CONFLICT_KEYS ) ) {
 				$arr[$name] += $value;
 			} else {
 				$keys = implode( ', ', array_keys( $conflicts ) );