.

crates/signed_git/src/lib.rs

@@ -309,6 +309,23 @@ pub fn worktree_all_commits(workdir: &Path) -> Result<Vec<FileCommit>> {
     all_commits(&gix::open(workdir)?)
 }
 
+/// The commit HEAD points to, like `git log -1`. Returns `Ok(None)` for a
+/// repository without commits yet (unborn HEAD).
+pub fn head_commit(repo: &gix::Repository) -> Result<Option<FileCommit>> {
+    let Some(head) = repo.head_id().ok() else {
+        return Ok(None);
+    };
+    let commit = head.object()?.into_commit();
+    let author = commit.author()?;
+    let message = commit.message()?;
+    Ok(Some(FileCommit {
+        id: commit.id().shorten_or_id().to_string(),
+        summary: String::from_utf8_lossy(message.title).trim().to_string(),
+        author: String::from_utf8_lossy(author.name).trim().to_string(),
+        time: author.time()?.seconds,
+    }))
+}
+
 /// Short names of local branches (`refs/heads/*`), sorted alphabetically.
 pub fn worktree_branches(workdir: &Path) -> Result<Vec<String>> {
     let repo = gix::open(workdir)?;
@@ -353,10 +370,12 @@ pub struct WorktreeSnapshot {
     pub readme: Option<Vec<u8>>,
     /// Branch HEAD points to (`None` when detached, e.g. on a tag).
     pub current_branch: Option<String>,
+    /// Commit HEAD points to, if any (see [`head_commit`]).
+    pub head_commit: Option<FileCommit>,
 }
 
-/// Snapshot the worktree after a branch/tag switch: entries, README and the
-/// branch HEAD points to, opening the repository once.
+/// Snapshot the worktree after a branch/tag switch: entries, README, the
+/// branch HEAD points to and its commit, opening the repository once.
 pub fn worktree_snapshot(workdir: &Path) -> Result<WorktreeSnapshot> {
     let repo = gix::open(workdir)?;
     let readme_path = find_readme(&repo)?;
@@ -369,6 +388,7 @@ pub fn worktree_snapshot(workdir: &Path) -> Result<WorktreeSnapshot> {
         readme_path,
         readme,
         current_branch: current_branch(&repo)?,
+        head_commit: head_commit(&repo)?,
     })
 }
 
@@ -672,6 +692,23 @@ mod tests {
         assert!(find_readme(&repo).expect("find").is_none());
     }
 
+    #[test]
+    fn head_commit_reports_head() {
+        let (_dir, repo) = fixture(&[("a.txt", b"one")]);
+
+        // Unborn HEAD: no commit yet.
+        assert!(head_commit(&repo).expect("head").is_none());
+
+        commit_all(&repo, "initial");
+        let head = head_commit(&repo).expect("head").expect("commit");
+        assert_eq!(
+            head.id,
+            repo.head_id().expect("head id").shorten_or_id().to_string()
+        );
+        assert_eq!(head.summary, "initial");
+        assert_eq!(head.author, "Test Author");
+    }
+
     #[test]
     fn worktree_branches_and_tags_list_short_names() {
         let (dir, repo) = fixture(&[("a.txt", b"one")]);
@@ -743,6 +780,10 @@ mod tests {
 
         let snapshot = worktree_snapshot(dir).expect("snapshot");
         assert_eq!(snapshot.current_branch.as_deref(), Some("feature"));
+        assert_eq!(
+            snapshot.head_commit.as_ref().expect("head commit").summary,
+            "feature work"
+        );
         assert_eq!(
             String::from_utf8(snapshot.readme.expect("readme")).expect("utf8"),
             "# feature"
@@ -763,6 +804,10 @@ mod tests {
 
         let snapshot = worktree_snapshot(dir).expect("snapshot");
         assert_eq!(snapshot.current_branch.as_deref(), Some(default.as_str()));
+        assert_eq!(
+            snapshot.head_commit.as_ref().expect("head commit").summary,
+            "initial"
+        );
         assert_eq!(
             String::from_utf8(snapshot.readme.expect("readme")).expect("utf8"),
             "# main"