- (overlay-put overlay 'bug-reference-url
- (format bug-reference-url-format
- (match-string-no-properties 1)))))))))
+ ;; Don't put a link if format is undefined
+ (when bug-reference-url-format
+ (overlay-put overlay 'bug-reference-url
+ (format bug-reference-url-format
+ (match-string-no-properties 1))))))))))