Merge pull request #1006 from github/fix-scanner-panic

skip scanner lines that are too short

lfs/scanner.go

@@ -370,20 +370,29 @@ func catFileBatchCheck(revs chan string) (chan string, error) {
 		scanner := bufio.NewScanner(cmd.Stdout)
 		for scanner.Scan() {
 			line := scanner.Text()
+			lineLen := len(line)
+
 			// Format is:
 			// <sha1> <type> <size>
 			// type is at a fixed spot, if we see that it's "blob", we can avoid
 			// splitting the line just to get the size.
-			if line[41:45] == "blob" {
-				size, err := strconv.Atoi(line[46:len(line)])
+			if lineLen < 46 {
+				continue
+			}
+
+			if line[41:45] != "blob" {
+				continue
+			}
+
+			size, err := strconv.Atoi(line[46:lineLen])
 			if err != nil {
 				continue
 			}
+
 			if size < blobSizeCutoff {
 				smallRevs <- line[0:40]
 			}
 		}
-		}
 
 		cmd.Wait()
 		close(smallRevs)