git-review-rebase: interleave added commits based on their position in the rebased branch.

Added commits were showing as the first commits in the rebase table as they
were added last to the commit_matches dictionnary.  It is fine when said
commits are added on top of the branch, like when we're working on the
linux kernel and add commits neutralizing kABI changes, but when using
git-review-rebase on branches imported from XenServer SRPMs, XenServer
folks often add some patchsets in the middle of their patch-queue - it is
nice in those cases to see the extra added commits interleaved with the
other matched right commits.

Signed-off-by: Quentin Casasnovas <quentin.casasnovas@vates.tech>

Author: casasnovas

scripts/git-review-rebase/src/git_review_rebase/commit_matching.py

@@ -72,11 +72,33 @@ def init_matches(self) -> None:
             if right_commit is not None and right_commit.id in right_commit_keys:
                 del right_commit_keys[right_commit.id]
 
-        # Remainders commits on the right side
+        right_position = {oid: idx for idx, oid in enumerate(self.right_range._rebased_commits)}
+
+        added_commits: list[tuple[pygit2.Oid, RebasedCommitMatch]] = []
         for right_commit_id in right_commit_keys:
             right_commit = self.repo.get(right_commit_id)
             assert isinstance(right_commit, pygit2.Commit)
-            self.commit_matches[right_commit_id] = RebasedCommitMatch(
-                None, right_commit, CommitMatchInfoFlag.Added
+            added_commits.append(
+                (right_commit_id, RebasedCommitMatch(None, right_commit, CommitMatchInfoFlag.Added))
             )
-        self.commit_matches.update(left_commit_matches)
+
+        # Interleave Added commits with left commits based on right-branch position.
+        # For each matched left commit, flush Added commits whose right-branch position
+        # comes before it. Dropped/PresentInRebaseOnto left commits (no position in
+        # right_position) are passed through immediately without flushing.
+        added_idx = 0
+        for left_commit_oid, left_match in left_commit_matches.items():
+            if left_match.right_commit is not None and left_match.right_commit.id in right_position:
+                current_right_pos = right_position[left_match.right_commit.id]
+                while (
+                    added_idx < len(added_commits)
+                    and right_position[added_commits[added_idx][0]] < current_right_pos
+                ):
+                    added_commit_id, added_commit_match_info = added_commits[added_idx]
+                    self.commit_matches[added_commit_id] = added_commit_match_info
+                    added_idx += 1
+            self.commit_matches[left_commit_oid] = left_match
+
+        # Append remaining Added commits (those after all matched right commits)
+        for added_commit_id, added_commit_match_info in added_commits[added_idx:]:
+            self.commit_matches[added_commit_id] = added_commit_match_info