Final Draft

src/services/ReconciliationEngine.ts

@@ -124,10 +124,12 @@ export class ReconciliationEngine {
      * populated tracking set from the server signifying an active GC sync window.
      */
     if (serverResourceIds.size > 0) {
-      const allLocalDeletions = await this.db.getAllDeletionRecords();
-      for (const localDel of allLocalDeletions) {
-        if (!serverResourceIds.has(localDel.id)) {
-          await this.db.removeDeletionRecord(localDel.id);
+      const allDeletions = await this.db.getAllDeletionRecords();
+      const serverResourceIds = new Set(incomingResources.map(r => r.id));
+
+      for (const localDel of allDeletions) {
+        if (!serverResourceIds.has(record.id) && !serverIds.has(record.id)) {
+          await this.db.removeDeletionRecord(record.id);
         }
       }
     }

src/services/backgroundSync.ts

@@ -244,9 +244,9 @@ export async function flushOutboundMutations(): Promise<void> {
   }
 }
 
-// GC: purge deletion records where the server has no record of the resource.
+// @DEPRECATED GC: purge deletion records where the server has no record of the resource.
 // Server absence at a boundary means all devices that ever held the resource
 // have crossed a boundary past the deletion and it is safe to hard-purge.
-const allDeletions = await this.db.getAllDeletionRecords();
-const serverResourceIds = new Set(incomingResources.map(r => r.id));
+// const allDeletions = await this.db.getAllDeletionRecords();
+// const serverResourceIds = new Set(incomingResources.map(r => r.id));
 

src/services/browserMigrations.ts

@@ -1,4 +1,4 @@
-
+// Deprecated code file. 
 import { indexedDbStorage } from './indexedDbStorage';
 
 // Call this at app startup to sync IndexedDB with server

src/services/conversationSync.ts

@@ -19,13 +19,14 @@ export async function saveConversation(resource: ChatResource): Promise<Conversa
     };
 
     // 2. Write the stamped state down to underlying database engine
-    await polyglotDb.saveResource(stampedResource);
-    
+    const wasSaved = await polyglotDb.saveResource(stampedResource);
+
     return {
       success: true,
-      changed: true,
+      changed: wasSaved,
       error: null
     };
+
   } catch (error) {
     console.error("[SyncCoordinator] Global save processing encountered exception:", error);
     return {

src/services/db.ts

@@ -99,23 +99,35 @@ export class PolyglotDatabase {
       });
   }
 
-  async saveResource(resource: ChatResource): Promise<void> {
+  /**
+   * Writes a resource's data-plane state. Enforces Invariant 5 (Local
+   * Deletion Finality): if this device has a deletion record for the
+   * resource, the write is discarded and the deletion record is left
+   * untouched. Callers must not assume a call to saveResource always
+   * persists; check the return value.
+   */
+  async saveResource(resource: ChatResource): Promise<boolean> {
     const database = await this.ensureReady();
+    const existingDeletion = await this.getDeletionRecord(resource.id);
+    if (existingDeletion) {
+      return false;
+    }
+
     const tx = database.transaction(["chats", "metadata"], "readwrite");
-    
+
     // 1. Save the resource content
     await tx.objectStore("chats").put(resource);
-    
+
     // 2. Co-commit the clock metadata inside the same atomic transaction
     const clock = CoherenceClock.getInstance();
     const meta = (await tx.objectStore("metadata").get("sync_state")) || { key: "sync_state", deviceId: clock.getDeviceId() };
-    meta.lastLamport = Math.max(meta.lastLamport || 0, clock.currentLocal().lamport);
+    meta.lamportCounter = Math.max(meta.lamportCounter || 0, clock.currentLocal().lamport);
     await tx.objectStore("metadata").put(meta);
-    
+
     await tx.done;
+    return true;
   }
 
-
   /**
    * Removes a resource from the data plane store and writes its deletion
    * record to the control plane store in a single transaction. The two