fix: the incorrect range generated when there are no parameters

1_parser/parser.go

@@ -131,7 +131,34 @@ func Parse(git *client.GitClient, ranges string) (*Scope, error) {
 		}
 
 		if latestTag != nil {
-			versions = append(versions, latestTag.Commit.Hash.String())
+			commit, err := git.GetPrevCommitOfTag(latestTag)
+
+			if err != nil {
+				return nil, errors.WithStack(err)
+			}
+
+			// if there is no prev tag
+			// tag is the HEAD
+			if commit == nil {
+				nextTag, err := git.NextTag(latestTag)
+
+				if err != nil {
+					return nil, errors.WithStack(err)
+				}
+
+				if nextTag != nil {
+					if commit, err := git.GetPrevCommitOfTag(nextTag); err != nil {
+						return nil, errors.WithStack(err)
+					} else {
+						versions = append(versions, commit.Hash.String())
+					}
+				} else {
+					versions = append(versions, "")
+				}
+			} else {
+				versions = append(versions, commit.Hash.String())
+			}
+
 		} else {
 			versions = append(versions, "")
 		}

cmd/whatchanged/main.go

@@ -58,7 +58,9 @@ OPTIONS:
                 --fmt=md.
 
 EXAMPLES:
-  # generate changelog from HEAD to <latest version>. equivalent to 'whatchanged HEAD~@0'
+  # generate changelog from HEAD to <latest version>.
+  # if HEAD is not the latest tag. then this should be a unreleased version
+  # otherwise it should be the latest version
   $ whatchanged
 
   # generate changelog of the specified version

internal/client/git.go

@@ -109,6 +109,27 @@ func (g *GitClient) TagN(offset int) (*Tag, error) {
 	return tag, nil
 }
 
+// Get next tag from the specified tag
+func (g *GitClient) PrevTag(target *Tag) (*Tag, error) {
+	tags, err := g.Tags()
+
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	for index, tag := range tags {
+		if tag.Hash == target.Hash {
+			i := index - 1
+			if i < 0 {
+				return nil, nil
+			}
+			return tags[i], nil
+		}
+	}
+
+	return nil, nil
+}
+
 // Get next tag from the specified tag
 func (g *GitClient) NextTag(target *Tag) (*Tag, error) {
 	tags, err := g.Tags()
@@ -478,6 +499,45 @@ func (g *GitClient) GetLastCommitOfTag(tag *Tag) (*object.Commit, error) {
 	}
 }
 
+func (g *GitClient) GetPrevCommitOfTag(tag *Tag) (*object.Commit, error) {
+	prevTag, err := g.PrevTag(tag)
+
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	options := git.LogOptions{}
+
+	if prevTag != nil {
+		options.From = prevTag.Commit.Hash
+	}
+
+	cIter, err := g.Repository.Log(&options)
+
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	var prevCommit *object.Commit
+
+	for {
+		if commit, err := cIter.Next(); err == io.EOF {
+			break
+		} else if err != nil {
+			return nil, errors.WithStack(err)
+		} else if commit == nil {
+			break
+		} else {
+			if commit.Hash.String() == tag.Commit.Hash.String() {
+				return prevCommit, nil
+			}
+			prevCommit = commit
+		}
+	}
+
+	return prevCommit, nil
+}
+
 func (g *GitClient) GetRemote() (*config.RemoteConfig, error) {
 	repoConfig, err := g.Repository.Config()