From 890a8e282f6edc589eead98a54c8137543135938 Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Sat, 23 Mar 2024 06:22:28 -0700
Subject: [PATCH] repo: update working copy to first divergent commit

---
 lib/src/repo.rs    | 12 +++++-------
 lib/src/rewrite.rs |  3 +--
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/lib/src/repo.rs b/lib/src/repo.rs
index 0162c700e..56a354ea8 100644
--- a/lib/src/repo.rs
+++ b/lib/src/repo.rs
@@ -732,7 +732,7 @@ pub struct MutableRepo {
     base_repo: Arc<ReadonlyRepo>,
     index: Box<dyn MutableIndex>,
     view: DirtyCell<View>,
-    rewritten_commits: HashMap<CommitId, HashSet<CommitId>>,
+    rewritten_commits: HashMap<CommitId, Vec<CommitId>>,
     abandoned_commits: HashSet<CommitId>,
 }
 
@@ -816,18 +816,16 @@ impl MutableRepo {
     /// docstring for `record_rewritten_commit` for details.
     pub fn set_rewritten_commit(&mut self, old_id: CommitId, new_id: CommitId) {
         assert_ne!(old_id, *self.store().root_commit_id());
-        self.rewritten_commits
-            .insert(old_id, std::iter::once(new_id).collect());
+        self.rewritten_commits.insert(old_id, vec![new_id]);
     }
 
     /// Record a commit as being rewritten into multiple other commits in this
     /// transaction.
     ///
     /// A later call to `rebase_descendants()` will update branches pointing to
-    /// `old_id` be conflicted and pointing to all pf `new_ids`. Working
-    /// copies pointing to `old_id` will be updated to point to an arbitrary
-    /// commit in `new_ids` (TODO: make it point to the first one). Descendants
-    /// of `old_id` will be left alone.
+    /// `old_id` be conflicted and pointing to all pf `new_ids`. Working copies
+    /// pointing to `old_id` will be updated to point to the first commit in
+    /// `new_ids``. Descendants of `old_id` will be left alone.
     pub fn set_divergent_rewrite(
         &mut self,
         old_id: CommitId,
diff --git a/lib/src/rewrite.rs b/lib/src/rewrite.rs
index 1d84d6aef..f3973ac9a 100644
--- a/lib/src/rewrite.rs
+++ b/lib/src/rewrite.rs
@@ -313,7 +313,7 @@ impl<'settings, 'repo> DescendantRebaser<'settings, 'repo> {
     pub fn new(
         settings: &'settings UserSettings,
         mut_repo: &'repo mut MutableRepo,
-        rewritten: HashMap<CommitId, HashSet<CommitId>>,
+        rewritten: HashMap<CommitId, Vec<CommitId>>,
         abandoned: HashSet<CommitId>,
     ) -> DescendantRebaser<'settings, 'repo> {
         let store = mut_repo.store();
@@ -372,7 +372,6 @@ impl<'settings, 'repo> DescendantRebaser<'settings, 'repo> {
             if new_commits.len() == 1 {
                 parent_mapping.insert(old_commit, vec![new_commits.into_iter().next().unwrap()]);
             } else {
-                // The call to index.heads() is mostly to get a predictable order
                 let new_commits = mut_repo.index().heads(&mut new_commits.iter());
                 parent_mapping.insert(old_commit.clone(), new_commits);
                 divergent.insert(old_commit);