diff --git a/lib/manager/bundler/extract.ts b/lib/manager/bundler/extract.ts
index b5a5dbb99c049dda0e072b17f8fc40a8e43fc294..b6b502eba6b46f1b375d4b6bf128c558ce5a1c98 100644
--- a/lib/manager/bundler/extract.ts
+++ b/lib/manager/bundler/extract.ts
@@ -106,7 +106,7 @@ export async function extractPackageFile(
         const sourceLineNumber = lineNumber;
         let sourceContent = '';
         let sourceLine = '';
-        while (lineNumber < lines.length && sourceLine !== 'end') {
+        while (lineNumber < lines.length && sourceLine.trim() !== 'end') {
           lineNumber += 1;
           sourceLine = lines[lineNumber];
           // istanbul ignore if