Merge pull request #41 from giuseppe/fix-empty-commit-range

git-validation: do not fail on an empty commit range

Author: vbatts

git/commits.go

@@ -13,6 +13,7 @@ import (
 // Commits returns a set of commits.
 // If commitrange is a git still range 12345...54321, then it will be isolated set of commits.
 // If commitrange is a single commit, all ancestor commits up through the hash provided.
+// If commitrange is an empty commit range, then nil is returned.
 func Commits(commitrange string) ([]CommitEntry, error) {
 	cmdArgs := []string{"git", "--no-pager", "log", `--pretty=format:%H`, commitrange}
 	if debug() {
@@ -23,6 +24,9 @@ func Commits(commitrange string) ([]CommitEntry, error) {
 		logrus.Errorf("mm[git] cmd: %q", strings.Join(cmdArgs, " "))
 		return nil, err
 	}
+	if len(output) == 0 {
+		return nil, nil
+	}
 	commitHashes := strings.Split(strings.TrimSpace(string(output)), "\n")
 	commits := make([]CommitEntry, len(commitHashes))
 	for i, commitHash := range commitHashes {