From 3ddf9f43293552c2d0dad5e70eb29152e8a47e0b Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Sat, 23 Mar 2024 14:49:29 -0700
Subject: [PATCH] repo: add parents of abandoned commit to parent_mapping

By adding the abandoned commit's parents to `parent_mapping`, we can
remove a bit more of the special handling of abandoned commitsin
`DescendantRebaser`.
---
 lib/src/repo.rs    | 8 +++++++-
 lib/src/rewrite.rs | 7 -------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/lib/src/repo.rs b/lib/src/repo.rs
index 2d9344fe2..838a65d5b 100644
--- a/lib/src/repo.rs
+++ b/lib/src/repo.rs
@@ -857,9 +857,15 @@ impl MutableRepo {
     /// The `rebase_descendants` logic will rebase the descendants of `old_id`
     /// to become the descendants of parent(s) of `old_id`. Any branches at
     /// `old_id` would be moved to the parent(s) of `old_id` as well.
+    // TODO: Propagate errors from commit lookup or take a Commit as argument.
     pub fn record_abandoned_commit(&mut self, old_id: CommitId) {
         assert_ne!(old_id, *self.store().root_commit_id());
-        self.abandoned.insert(old_id);
+        self.divergent.remove(&old_id);
+        self.abandoned.insert(old_id.clone());
+        // Descendants should be rebased onto the commit's parents
+        let old_commit = self.store().get_commit(&old_id).unwrap();
+        self.parent_mapping
+            .insert(old_id, old_commit.parent_ids().to_vec());
     }
 
     fn clear_descendant_rebaser_plans(&mut self) {
diff --git a/lib/src/rewrite.rs b/lib/src/rewrite.rs
index b7403a992..740b807f8 100644
--- a/lib/src/rewrite.rs
+++ b/lib/src/rewrite.rs
@@ -540,13 +540,6 @@ impl<'settings, 'repo> DescendantRebaser<'settings, 'repo> {
         }
         let old_parent_ids = old_commit.parent_ids();
         let new_parent_ids = self.new_parents(old_parent_ids);
-        if self.mut_repo.abandoned.contains(&old_commit_id) {
-            // Update the `new_parents` map so descendants are rebased correctly.
-            self.mut_repo
-                .parent_mapping
-                .insert(old_commit_id.clone(), new_parent_ids.clone());
-            return Ok(());
-        }
         if new_parent_ids == old_parent_ids {
             // The commit is already in place.
             return Ok(());