Use gix for simple ref-walk that won't go past the merge-base.

Author: Byron

Cargo.lock

@@ -43,7 +43,7 @@ reqwest = { version = "0.12.4", features = ["json"] }
 once_cell = "1.19"
 pretty_assertions = "1.4"
 gitbutler-testsupport.workspace = true
-gix = { workspace = true, features = ["max-performance-safe"] }
+gix = { workspace = true, features = ["max-performance"] }
 gitbutler-git = { workspace = true, features = ["test-askpass-path"] }
 glob = "0.3.1"
 serial_test = "3.1.1"

crates/gitbutler-branch-actions/Cargo.toml

@@ -426,6 +426,8 @@ pub fn get_branch_listing_details(
         .filter_map(Result::ok)
         .collect();
     let repo = ctx.repository();
+    let mut repo2 = ctx.gix_repository_minimal()?;
+    repo2.object_cache_size_if_unset(4 * 1024);
     let branches = list_branches(ctx, None, Some(branch_names))?;
 
     let (default_target_current_upstream_commit_id, default_target_seen_at_last_update) = {
@@ -465,23 +467,29 @@ pub fn get_branch_listing_details(
 
         let head = branch.head;
 
-        let mut revwalk = repo.revwalk()?;
-        revwalk.push(head)?;
-        revwalk.hide(base)?;
-        let mut commits = Vec::new();
+        let gix_base = git2_to_gix_object_id(base);
+        // TODO: make this API nicer, maybe have one that is not based on `ancestors()` but
+        //       similar to revwalk because it's so common?
+        let revwalk = git2_to_gix_object_id(head)
+            .attach(&repo2)
+            .ancestors()
+            .selected(|id| id != gix_base)?;
+        let mut num_commits = 0;
         let mut authors = HashSet::new();
-        for oid in revwalk {
-            let commit = repo.find_commit(oid?)?;
-            authors.insert(commit.author().into());
-            commits.push(commit);
+        for commit_info in revwalk {
+            let commit_info = commit_info?;
+            // TODO: offer direct `find_<kind>` methods.
+            let commit = repo2.find_object(commit_info.id)?.try_into_commit()?;
+            authors.insert(commit.author()?.into());
+            num_commits += 1;
         }
         let branch_data = BranchListingDetails {
             name: branch.name,
             lines_added: diff_stats.insertions(),
             lines_removed: diff_stats.deletions(),
             number_of_files: diff_stats.files_changed(),
             authors: authors.into_iter().collect(),
-            number_of_commits: commits.len(),
+            number_of_commits: num_commits,
         };
         enriched_branches.push(branch_data);
     }

crates/gitbutler-branch-actions/src/branch.rs

@@ -10075,4 +10075,5 @@ git clone remote revwalk-repo
 
   # pretend the remote is at the same state as our local `main`
   git update-ref refs/remotes/origin/main main
+  git gc --aggressive
 )

crates/gitbutler-branch-actions/tests/fixtures/branch-details-benches.sh

@@ -71,7 +71,8 @@ impl CommandContext {
         &self.git_repository
     }
 
-    /// Return a currently newly opened `gitoxide` repository.
+    /// Return a newly opened `gitoxide` repository, with all configuration available
+    /// to correctly figure out author and committer names (i.e. with most global configuration loaded).
     ///
     /// ### Note
     ///
@@ -84,4 +85,16 @@ impl CommandContext {
     pub fn gix_repository(&self) -> Result<gix::Repository> {
         Ok(gix::open(self.repository().path())?)
     }
+
+    /// Return a newly opened `gitoxide` repository with only the repository-local configuration
+    /// available. This is a little faster as it has to open less files upon startup.
+    ///
+    /// Such repositories are only useful for reference and object-access, but *can't be used* to create
+    /// commits, fetch or push.
+    pub fn gix_repository_minimal(&self) -> Result<gix::Repository> {
+        Ok(gix::open_opts(
+            self.repository().path(),
+            gix::open::Options::isolated(),
+        )?)
+    }
 }