feat(changelog): support generating changelog based on tagging status

Cargo.lock

@@ -304,6 +304,7 @@ dependencies = [
  "config",
  "git-conventional",
  "git2",
+ "indexmap",
  "pretty_assertions",
  "regex",
  "serde",
@@ -364,6 +365,12 @@ dependencies = [
  "walkdir",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
+
 [[package]]
 name = "heck"
 version = "0.3.2"
@@ -426,6 +433,16 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "indexmap"
+version = "1.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "824845a0bf897a9042383849b02c1bc219c2383772efcd5c6f9766fa4b81aef3"
+dependencies = [
+ "autocfg",
+ "hashbrown",
+]
+
 [[package]]
 name = "itoa"
 version = "0.4.7"

git-cliff-core/Cargo.toml

@@ -19,6 +19,7 @@ serde_derive = "1.0"
 tera = "1.9.0"
 regex = "1.5.4"
 serde_regex = "1.1.0"
+indexmap = "1.6.2"
 
 [dependencies.config]
 version = "0.11.0"

git-cliff-core/src/repo.rs

@@ -8,7 +8,7 @@ use git2::{
 	Repository as GitRepository,
 	Sort,
 };
-use std::collections::HashMap;
+use indexmap::IndexMap;
 use std::io;
 use std::path::PathBuf;
 
@@ -54,8 +54,8 @@ impl Repository {
 	/// Parses and returns a commit-tag map.
 	///
 	/// It collects lightweight and annotated tags.
-	pub fn tags(&self, pattern: &str) -> Result<HashMap<String, String>> {
-		let mut tags = HashMap::new();
+	pub fn tags(&self, pattern: &str) -> Result<IndexMap<String, String>> {
+		let mut tags = IndexMap::new();
 		let tag_names = self.inner.tag_names(Some(pattern))?;
 		for name in tag_names.iter().flatten().map(String::from) {
 			let obj = self.inner.revparse_single(&name)?;

git-cliff/src/args.rs

@@ -35,6 +35,12 @@ pub struct Opt {
 	/// Sets the tag for the latest version.
 	#[structopt(short, long, env, value_name = "TAG", allow_hyphen_values = true)]
 	pub tag:        Option<String>,
+	/// Processes the commits starting from the latest tag.
+	#[structopt(short, long)]
+	pub latest:     bool,
+	/// Processes the commits that do not belong to a tag.
+	#[structopt(short, long)]
+	pub unreleased: bool,
 	/// Sets the commit range to process.
 	pub range:      Option<String>,
 }

git-cliff/src/main.rs

@@ -27,7 +27,20 @@ fn main() -> Result<()> {
 	let repository =
 		Repository::init(args.repository.unwrap_or(env::current_dir()?))?;
 	let mut tags = repository.tags(&config.git.tag_pattern)?;
-	let commits = repository.commits(args.range)?;
+	let mut commit_range = args.range;
+	if args.unreleased {
+		if let Some(last_tag) = tags.last().map(|(k, _)| k) {
+			commit_range = Some(format!("{}..HEAD", last_tag));
+		}
+	} else if args.latest {
+		if let (Some(tag1), Some(tag2)) = (
+			tags.get_index(tags.len() - 2).map(|(k, _)| k),
+			tags.get_index(tags.len() - 1).map(|(k, _)| k),
+		) {
+			commit_range = Some(format!("{}..{}", tag1, tag2));
+		}
+	}
+	let commits = repository.commits(commit_range)?;
 
 	if let Some(tag) = args.tag {
 		if let Some(commit_id) = commits.first().map(|c| c.id().to_string()) {