feat(changelog): support generating a changelog scoped to a directory (#11)

README.md

@@ -124,7 +124,8 @@ git-cliff [FLAGS] [OPTIONS] [RANGE]
 ```
 -c, --config <PATH>        Sets the configuration file [env: CONFIG=]  [default: cliff.toml]
 -w, --workdir <PATH>       Sets the working directory [env: WORKDIR=]
--r, --repository <PATH>    Sets the repository to parse commits from [env: REPOSITORY=]
+-r, --repository <PATH>    Sets the git repository [env: REPOSITORY=]
+    --commit-path <PATH>   Sets the directory to parse commits from [env: COMMIT_PATH=]
 -p, --prepend <PATH>       Prepends entries to the given changelog file [env: PREPEND=]
 -o, --output <PATH>        Writes output to the given file [env: OUTPUT=]
 -t, --tag <TAG>            Sets the tag for the latest version [env: TAG=]
@@ -161,7 +162,7 @@ Set a tag for the "unreleased" changes:
 git cliff --tag 1.0.0
 ```
 
-Create a changelog for a certain part of git history:
+Generate a changelog for a certain part of git history:
 
 ```sh
 # only takes the latest tag into account
@@ -178,6 +179,12 @@ git cliff 4c7b043..HEAD
 git cliff HEAD~2..
 ```
 
+Generate a changelog scoped to a specific directory (useful for monorepos):
+
+```sh
+git cliff --commit-path project1/
+```
+
 Save the changelog file to the specified file:
 
 ```sh

git-cliff-core/src/repo.rs

@@ -36,7 +36,11 @@ impl Repository {
 	/// Parses and returns the commits.
 	///
 	/// Sorts the commits by their time.
-	pub fn commits(&self, range: Option<String>) -> Result<Vec<Commit>> {
+	pub fn commits(
+		&self,
+		range: Option<String>,
+		path: Option<String>,
+	) -> Result<Vec<Commit>> {
 		let mut revwalk = self.inner.revwalk()?;
 		revwalk.set_sorting(Sort::TIME | Sort::TOPOLOGICAL)?;
 		if let Some(range) = range {
@@ -44,10 +48,32 @@ impl Repository {
 		} else {
 			revwalk.push_head()?;
 		}
-		Ok(revwalk
+		let mut commits: Vec<Commit> = revwalk
 			.filter_map(|id| id.ok())
 			.filter_map(|id| self.inner.find_commit(id).ok())
-			.collect())
+			.collect();
+		if let Some(commit_path) = path {
+			commits = commits
+				.into_iter()
+				.filter(|commit| {
+					if let Ok(prev_commit) = commit.parent(0) {
+						if let Ok(diff) = self.inner.diff_tree_to_tree(
+							commit.tree().ok().as_ref(),
+							prev_commit.tree().ok().as_ref(),
+							None,
+						) {
+							return diff.deltas().any(|delta| {
+								delta.new_file().path().map_or(false, |path| {
+									path.starts_with(&commit_path)
+								})
+							});
+						}
+					}
+					false
+				})
+				.collect()
+		}
+		Ok(commits)
 	}
 
 	/// Parses and returns a commit-tag map.
@@ -125,7 +151,7 @@ mod test {
 				.unwrap()
 				.to_path_buf(),
 		)?;
-		let commits = repository.commits(None)?;
+		let commits = repository.commits(None, None)?;
 		let last_commit = AppCommit::from(&commits.first().unwrap().clone());
 		assert_eq!(get_last_commit_hash()?, last_commit.id);
 		if let Err(e) = last_commit.into_conventional() {

git-cliff/src/args.rs

@@ -20,7 +20,7 @@ use structopt::StructOpt;
 pub struct Opt {
 	/// Increases the logging verbosity.
 	#[structopt(short, long, parse(from_occurrences), alias = "debug")]
-	pub verbose:    u8,
+	pub verbose:     u8,
 	/// Sets the configuration file.
 	#[structopt(
 		short,
@@ -29,22 +29,25 @@ pub struct Opt {
 		value_name = "PATH",
 		default_value = DEFAULT_CONFIG,
 	)]
-	pub config:     PathBuf,
+	pub config:      PathBuf,
 	/// Sets the working directory.
 	#[structopt(short, long, env, value_name = "PATH")]
-	pub workdir:    Option<PathBuf>,
-	/// Sets the repository to parse commits from.
+	pub workdir:     Option<PathBuf>,
+	/// Sets the git repository.
 	#[structopt(short, long, env, value_name = "PATH")]
-	pub repository: Option<PathBuf>,
+	pub repository:  Option<PathBuf>,
+	/// Sets the directory to parse commits from.
+	#[structopt(long, env, value_name = "PATH")]
+	pub commit_path: Option<String>,
 	/// Prepends entries to the given changelog file.
 	#[structopt(short, long, env, value_name = "PATH")]
-	pub prepend:    Option<PathBuf>,
+	pub prepend:     Option<PathBuf>,
 	/// Writes output to the given file.
 	#[structopt(short, long, env, value_name = "PATH")]
-	pub output:     Option<PathBuf>,
+	pub output:      Option<PathBuf>,
 	/// Sets the tag for the latest version.
 	#[structopt(short, long, env, value_name = "TAG", allow_hyphen_values = true)]
-	pub tag:        Option<String>,
+	pub tag:         Option<String>,
 	/// Sets the template for the changelog body.
 	#[structopt(
 		short,
@@ -53,16 +56,16 @@ pub struct Opt {
 		value_name = "TEMPLATE",
 		allow_hyphen_values = true
 	)]
-	pub body:       Option<String>,
+	pub body:        Option<String>,
 	/// Writes the default configuration file to cliff.toml
 	#[structopt(short, long)]
-	pub init:       bool,
+	pub init:        bool,
 	/// Processes the commits starting from the latest tag.
 	#[structopt(short, long)]
-	pub latest:     bool,
+	pub latest:      bool,
 	/// Processes the commits that do not belong to a tag.
 	#[structopt(short, long)]
-	pub unreleased: bool,
+	pub unreleased:  bool,
 	/// Strips the given parts from the changelog.
 	#[structopt(
 		short,
@@ -70,8 +73,8 @@ pub struct Opt {
 		value_name = "PART",
 		possible_values = &["header", "footer", "all"]
 	)]
-	pub strip:      Option<String>,
+	pub strip:       Option<String>,
 	/// Sets the commit range to process.
 	#[structopt(value_name = "RANGE")]
-	pub range:      Option<String>,
+	pub range:       Option<String>,
 }

git-cliff/src/lib.rs

@@ -122,7 +122,7 @@ pub fn run(mut args: Opt) -> Result<()> {
 			commit_range = Some(format!("{}..{}", tag1, tag2));
 		}
 	}
-	let commits = repository.commits(commit_range)?;
+	let commits = repository.commits(commit_range, args.commit_path)?;
 
 	// Update tags.
 	if let Some(tag) = args.tag {