fix: shell

server/tests/revision_branch.rs

@@ -218,3 +218,95 @@ async fn editing_a_logical_input_discards_its_active_suffix() {
         vec![original, suffix]
     );
 }
+
+#[tokio::test]
+async fn retry_reuses_only_the_matching_initial_child_chain() {
+    let (_directory, store) = fixtures::temp_store().await;
+    let conversation_id = ConversationId::new("retry-conversation");
+    let root = store.ensure_conversation(&conversation_id).await.unwrap();
+    let first = prepared("first-run", &conversation_id, root);
+    store.claim_run(&first).await.unwrap();
+
+    let context = fixtures::user("request-context:event", "context");
+    let context_revision = store
+        .append_revision(
+            &conversation_id,
+            &first.run_id,
+            root,
+            std::slice::from_ref(&context),
+        )
+        .await
+        .unwrap();
+    let runtime = cursor_server::model::RuntimeEvent {
+        event_id: "cursor:user:stable-id:version".into(),
+        text: "query".into(),
+    }
+    .into_message();
+
+    let (partial_revision, partial_count) = store
+        .match_revision_prefix(&conversation_id, root, &[context.clone(), runtime.clone()])
+        .await
+        .unwrap();
+    assert_eq!(partial_revision, context_revision);
+    assert_eq!(partial_count, 1);
+
+    let runtime_revision = store
+        .append_revision(
+            &conversation_id,
+            &first.run_id,
+            context_revision,
+            std::slice::from_ref(&runtime),
+        )
+        .await
+        .unwrap();
+    let suffix = fixtures::user("old-answer", "old answer");
+    let old_head = store
+        .append_revision(
+            &conversation_id,
+            &first.run_id,
+            runtime_revision,
+            std::slice::from_ref(&suffix),
+        )
+        .await
+        .unwrap();
+
+    let (retry_base, reused) = store
+        .match_revision_prefix(&conversation_id, root, &[context.clone(), runtime.clone()])
+        .await
+        .unwrap();
+    assert_eq!(retry_base, runtime_revision);
+    assert_eq!(reused, 2);
+    assert_eq!(
+        store.load_revision_messages(retry_base).await.unwrap(),
+        vec![context.clone(), runtime.clone()]
+    );
+    let retry = prepared("retry-run", &conversation_id, retry_base);
+    let claimed = store.claim_run(&retry).await.unwrap();
+    assert_eq!(claimed.replaced_run_id.as_ref(), Some(&first.run_id));
+    let first_status: String = sqlx::query_scalar("SELECT status FROM runs WHERE run_id = ?")
+        .bind(first.run_id.as_str())
+        .fetch_one(store.pool())
+        .await
+        .unwrap();
+    assert_eq!(first_status, "cancelled");
+
+    let changed = cursor_server::model::RuntimeEvent {
+        event_id: "cursor:user:stable-id:changed-version".into(),
+        text: "edited query".into(),
+    }
+    .into_message();
+    let (changed_base, reused) = store
+        .match_revision_prefix(&conversation_id, root, &[context, changed])
+        .await
+        .unwrap();
+    assert_eq!(changed_base, context_revision);
+    assert_eq!(reused, 1);
+    assert_eq!(
+        store.load_revision_messages(old_head).await.unwrap(),
+        vec![
+            fixtures::user("request-context:event", "context"),
+            runtime,
+            suffix
+        ]
+    );
+}