fix: prevent placeholders from overwriting real checkpoints

eggfriedrice24 · eggfriedrice24 · commit 420c3fab7298 · 2026-03-10T23:31:56.000Z
ProviderRuntimeIngestion fires multiple turn.diff.updated events per
turn. Each dispatches a placeholder checkpoint that the projector would
blindly replace by turnId, clobbering the real git capture from
CheckpointReactor. Also, using thread.checkpoints.length + 1 for
checkpointTurnCount produced unstable values after dedup.

Two fixes:
1. Projector: skip incoming "missing" checkpoints when a non-placeholder
   entry already exists for that turnId
2. ProviderRuntimeIngestion: skip placeholder dispatch entirely if a
   checkpoint already exists for the turnId, and use max turnCount + 1
   instead of length + 1
diff --git a/apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.ts b/apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.ts
@@ -1064,22 +1064,34 @@ const make = Effect.gen(function* () {
       if (event.type === "turn.diff.updated") {
         const turnId = toTurnId(event.turnId);
         if (turnId && (yield* isGitRepoForThread(thread.id))) {
-          const assistantMessageId = MessageId.makeUnsafe(
-            `assistant:${event.itemId ?? event.turnId ?? event.eventId}`,
-          );
-          yield* orchestrationEngine.dispatch({
-            type: "thread.turn.diff.complete",
-            commandId: providerCommandId(event, "thread-turn-diff-complete"),
-            threadId: thread.id,
-            turnId,
-            completedAt: now,
-            checkpointRef: CheckpointRef.makeUnsafe(`provider-diff:${event.eventId}`),
-            status: "missing",
-            files: [],
-            assistantMessageId,
-            checkpointTurnCount: thread.checkpoints.length + 1,
-            createdAt: now,
-          });
+          // Skip if a checkpoint already exists for this turn. A real
+          // (non-placeholder) capture from CheckpointReactor should not
+          // be clobbered, and dispatching a duplicate placeholder for the
+          // same turnId would produce an unstable checkpointTurnCount.
+          if (thread.checkpoints.some((c) => c.turnId === turnId)) {
+            // Already tracked; no-op.
+          } else {
+            const assistantMessageId = MessageId.makeUnsafe(
+              `assistant:${event.itemId ?? event.turnId ?? event.eventId}`,
+            );
+            const maxTurnCount = thread.checkpoints.reduce(
+              (max, c) => Math.max(max, c.checkpointTurnCount),
+              0,
+            );
+            yield* orchestrationEngine.dispatch({
+              type: "thread.turn.diff.complete",
+              commandId: providerCommandId(event, "thread-turn-diff-complete"),
+              threadId: thread.id,
+              turnId,
+              completedAt: now,
+              checkpointRef: CheckpointRef.makeUnsafe(`provider-diff:${event.eventId}`),
+              status: "missing",
+              files: [],
+              assistantMessageId,
+              checkpointTurnCount: maxTurnCount + 1,
+              createdAt: now,
+            });
+          }
         }
       }
 
diff --git a/apps/server/src/orchestration/projector.ts b/apps/server/src/orchestration/projector.ts
@@ -500,6 +500,16 @@ export function projectEvent(
           "checkpoint",
         );
 
+        // Do not let a placeholder (status "missing") overwrite a checkpoint
+        // that has already been captured with a real git ref (status "ready").
+        // ProviderRuntimeIngestion may fire multiple turn.diff.updated events
+        // per turn; without this guard later placeholders would clobber the
+        // real capture dispatched by CheckpointReactor.
+        const existing = thread.checkpoints.find((entry) => entry.turnId === checkpoint.turnId);
+        if (existing && existing.status !== "missing" && checkpoint.status === "missing") {
+          return nextBase;
+        }
+
         const checkpoints = [
           ...thread.checkpoints.filter((entry) => entry.turnId !== checkpoint.turnId),
           checkpoint,
