diff --git a/lib/src/repo.rs b/lib/src/repo.rs
index 14cfb6fcb..fabf34a62 100644
--- a/lib/src/repo.rs
+++ b/lib/src/repo.rs
@@ -518,6 +518,10 @@ impl MutableRepo {
         self.abandoned_commits.clear();
     }
 
+    pub fn has_rewrites(&self) -> bool {
+        !(self.rewritten_commits.is_empty() && self.abandoned_commits.is_empty())
+    }
+
     /// Creates a `DescendantRebaser` to rebase descendants of the recorded
     /// rewritten and abandoned commits.
     pub fn create_descendant_rebaser<'settings, 'repo>(
@@ -533,7 +537,7 @@ impl MutableRepo {
     }
 
     pub fn rebase_descendants(&mut self, settings: &UserSettings) -> usize {
-        if self.rewritten_commits.is_empty() && self.abandoned_commits.is_empty() {
+        if !self.has_rewrites() {
             // Optimization
             return 0;
         }
diff --git a/lib/src/transaction.rs b/lib/src/transaction.rs
index b1abec09b..4e9cd48b7 100644
--- a/lib/src/transaction.rs
+++ b/lib/src/transaction.rs
@@ -69,6 +69,11 @@ impl Transaction {
     /// operation will not be seen when loading the repo at head.
     pub fn write(mut self) -> UnpublishedOperation {
         let mut_repo = self.repo.take().unwrap();
+        // TODO: Should we instead just do the rebasing here if necessary?
+        assert!(
+            !mut_repo.has_rewrites(),
+            "BUG: Descendants have not been rebased after the last rewrites."
+        );
         let base_repo = mut_repo.base_repo().clone();
         let (mut_index, view) = mut_repo.consume();
         let index = base_repo.index_store().write_index(mut_index).unwrap();
diff --git a/lib/tests/test_commit_builder.rs b/lib/tests/test_commit_builder.rs
index f3d8e7790..e5f4cfff4 100644
--- a/lib/tests/test_commit_builder.rs
+++ b/lib/tests/test_commit_builder.rs
@@ -112,6 +112,7 @@ fn test_rewrite(use_git: bool) {
         CommitBuilder::for_rewrite_from(&rewrite_settings, &store, &initial_commit)
             .set_tree(rewritten_tree.id().clone())
             .write_to_repo(tx.mut_repo());
+    tx.mut_repo().rebase_descendants(&settings);
     tx.commit();
     assert_eq!(rewritten_commit.parents(), vec![store.root_commit()]);
     assert_eq!(
diff --git a/lib/tests/test_merge_trees.rs b/lib/tests/test_merge_trees.rs
index af281ee30..02bb6f125 100644
--- a/lib/tests/test_merge_trees.rs
+++ b/lib/tests/test_merge_trees.rs
@@ -620,6 +620,7 @@ fn test_simplify_conflict_after_resolving_parent(use_git: bool) {
         .set_tree(tree_b3.id().clone())
         .write_to_repo(tx.mut_repo());
     let commit_c3 = rebase_commit(&settings, tx.mut_repo(), &commit_c2, &[commit_b3]);
+    tx.mut_repo().rebase_descendants(&settings);
     let repo = tx.commit();
 
     // The conflict should now be resolved.
diff --git a/lib/tests/test_operations.rs b/lib/tests/test_operations.rs
index 5f68001ce..51a491d9b 100644
--- a/lib/tests/test_operations.rs
+++ b/lib/tests/test_operations.rs
@@ -154,28 +154,27 @@ fn test_isolation(use_git: bool) {
     let rewrite1 = CommitBuilder::for_rewrite_from(&settings, repo.store(), &initial)
         .set_description("rewrite1".to_string())
         .write_to_repo(mut_repo1);
+    mut_repo1.rebase_descendants(&settings);
     let rewrite2 = CommitBuilder::for_rewrite_from(&settings, repo.store(), &initial)
         .set_description("rewrite2".to_string())
         .write_to_repo(mut_repo2);
+    mut_repo2.rebase_descendants(&settings);
 
     // Neither transaction has committed yet, so each transaction sees its own
     // commit.
     assert_heads(repo.as_repo_ref(), vec![initial.id()]);
-    assert_heads(mut_repo1.as_repo_ref(), vec![initial.id(), rewrite1.id()]);
-    assert_heads(mut_repo2.as_repo_ref(), vec![initial.id(), rewrite2.id()]);
+    assert_heads(mut_repo1.as_repo_ref(), vec![rewrite1.id()]);
+    assert_heads(mut_repo2.as_repo_ref(), vec![rewrite2.id()]);
 
     // The base repo and tx2 don't see the commits from tx1.
     tx1.commit();
     assert_heads(repo.as_repo_ref(), vec![initial.id()]);
-    assert_heads(mut_repo2.as_repo_ref(), vec![initial.id(), rewrite2.id()]);
+    assert_heads(mut_repo2.as_repo_ref(), vec![rewrite2.id()]);
 
     // The base repo still doesn't see the commits after both transactions commit.
     tx2.commit();
     assert_heads(repo.as_repo_ref(), vec![initial.id()]);
     // After reload, the base repo sees both rewrites.
     let repo = repo.reload();
-    assert_heads(
-        repo.as_repo_ref(),
-        vec![initial.id(), rewrite1.id(), rewrite2.id()],
-    );
+    assert_heads(repo.as_repo_ref(), vec![rewrite1.id(), rewrite2.id()]);
 }