feat(git): remove the include_root boolean flag

Use the fact that a range contains (or doesn't) contain
".." as a discriminant between the two cases:

- ".." means full (left-exclusive) range between two commits;
- no ".." means everything from the root commit (inclusive) to
the commit sha in the range

git-cliff-core/src/repo.rs

@@ -72,21 +72,18 @@ impl Repository {
 	pub fn commits(
 		&self,
 		range: Option<&str>,
-		include_root: bool,
 		include_path: Option<Vec<Pattern>>,
 		exclude_path: Option<Vec<Pattern>>,
 	) -> Result<Vec<Commit>> {
 		let mut revwalk = self.inner.revwalk()?;
 		revwalk.set_sorting(Sort::TOPOLOGICAL)?;
 		if let Some(range) = range {
-			// Push only the last range commit if we need to start at root.
-			if include_root {
-				if let Some(dots_index) = range.find("..") {
-					revwalk.push(Oid::from_str(&range[dots_index + 2..])?)?;
-				}
-			} else {
-				revwalk.push_range(range)?;
-			}
+            if range.contains("..") {
+                revwalk.push_range(range)?;
+            } else {
+                // when we get a single sha as our "range" => start at root.
+                revwalk.push(Oid::from_str(&range)?)?;
+            }
 		} else {
 			revwalk.push_head()?;
 		}
@@ -508,7 +505,7 @@ mod test {
 	#[test]
 	fn get_latest_commit() -> Result<()> {
 		let repository = get_repository()?;
-		let commits = repository.commits(None, false, None, None)?;
+		let commits = repository.commits(None, None, None)?;
 		let last_commit =
 			AppCommit::from(&commits.first().expect("no commits found").clone());
 		assert_eq!(get_last_commit_hash()?, last_commit.id);
@@ -609,7 +606,9 @@ mod test {
 	#[test]
 	fn includes_root_commit() -> Result<()> {
 		let repository = get_repository()?;
-		let commits = repository.commits(None, true, None, None)?;
+        // a close descendant of the root commit
+        let range = Some("eea3914c7ab07472841aa85c36d11bdb2589a234");
+        let commits = repository.commits(range, None, None)?;
 		let root_commit =
 			AppCommit::from(&commits.last().expect("no commits found").clone());
 		assert_eq!(get_root_commit_hash()?, root_commit.id);

git-cliff/src/lib.rs

@@ -160,20 +160,22 @@ fn process_repository<'a>(
 
 	// Parse commits.
 	let mut commit_range = args.range.clone();
-	let mut include_root = false;
 	if args.unreleased {
 		if let Some(last_tag) = tags.last().map(|(k, _)| k) {
 			commit_range = Some(format!("{last_tag}..HEAD"));
 		}
 	} else if args.latest || args.current {
 		if tags.len() < 2 {
-			let commits = repository.commits(None, false, None, None)?;
+			let commits = repository.commits(None, None, None)?;
 			if let (Some(tag1), Some(tag2)) = (
 				commits.last().map(|c| c.id().to_string()),
 				tags.get_index(0).map(|(k, _)| k),
 			) {
-				commit_range = Some(format!("{tag1}..{tag2}"));
-				include_root = true;
+                if tags.len() == 1 {
+                    commit_range = Some(tag2.to_owned());
+                } else {
+                    commit_range = Some(format!("{tag1}..{tag2}"));
+                }
 			}
 		} else {
 			let mut tag_index = tags.len() - 2;
@@ -210,7 +212,6 @@ fn process_repository<'a>(
 	}
 	let mut commits = repository.commits(
 		commit_range.as_deref(),
-		include_root,
 		args.include_path.clone(),
 		args.exclude_path.clone(),
 	)?;