fix(sync): use stable dedup key and skip threads when head unresolved

packages/backend/convex/githubSync.ts

@@ -16,6 +16,7 @@ import {
   listPullRequests,
   syncForkBranch,
 } from './githubClient';
+import { maintenanceDedupKey } from './maintenanceDedup';
 import { shouldAutoSync, shouldCreateReviewThread } from './syncGating';
 
 const getRequiredUserId = async (ctx: ActionCtx) => {
@@ -244,6 +245,32 @@ const refreshOwnedSpoon = async (
       } catch (syncError) {
         const message =
           syncError instanceof Error ? syncError.message : String(syncError);
+        const dedupKey = maintenanceDedupKey({
+          mergeBaseSha: upstreamCompare.mergeBaseSha ?? forkCompare.mergeBaseSha,
+          headSha: upstreamCompare.headSha,
+        });
+        if (!dedupKey) {
+          console.warn(
+            'Skipping maintenance thread: upstream head SHA unresolvable for spoon',
+            spoonId,
+          );
+          await ctx.runMutation(internal.syncRuns.patchInternal, {
+            syncRunId,
+            status: 'failed',
+            error: `${message} (skipped maintenance thread: could not resolve upstream head SHA)`,
+          });
+          await ctx.runMutation(internal.spoons.patchSyncFields, {
+            spoonId,
+            syncStatus: 'conflict',
+            lastError: message,
+          });
+          return {
+            success: true,
+            status: 'unknown' as const,
+            upstreamAheadBy: upstreamCompare.aheadBy,
+            forkAheadBy: forkCompare.aheadBy,
+          };
+        }
         const threadId = await ctx.runMutation(
           internal.threads.createMaintenanceThread,
           {
@@ -253,7 +280,8 @@ const refreshOwnedSpoon = async (
             title: `Resolve upstream sync conflict for ${spoon.name}`,
             summary: `GitHub refused the automatic upstream sync: ${message}`,
             upstreamFrom: upstreamCompare.mergeBaseSha,
-            upstreamTo: upstreamCompare.headSha ?? `${Date.now()}`,
+            upstreamTo: upstreamCompare.headSha,
+            dedupKey,
             forkHeadAtCreation: forkCompare.headSha,
             mergeBaseAtCreation:
               upstreamCompare.mergeBaseSha ?? forkCompare.mergeBaseSha,
@@ -283,6 +311,22 @@ const refreshOwnedSpoon = async (
     }
 
     if (shouldCreateReviewThread({ autoReviewEnabled }, { status })) {
+      const dedupKey = maintenanceDedupKey({
+        mergeBaseSha: upstreamCompare.mergeBaseSha ?? forkCompare.mergeBaseSha,
+        headSha: upstreamCompare.headSha,
+      });
+      if (!dedupKey) {
+        console.warn(
+          'Skipping maintenance thread: upstream head SHA unresolvable for spoon',
+          spoonId,
+        );
+        await ctx.runMutation(internal.syncRuns.patchInternal, {
+          syncRunId,
+          status: 'failed',
+          error:
+            'Could not resolve upstream head SHA; skipping maintenance thread.',
+        });
+      } else {
         const threadId = await ctx.runMutation(
           internal.threads.createMaintenanceThread,
           {
@@ -292,7 +336,8 @@ const refreshOwnedSpoon = async (
             title: `Review upstream changes for ${spoon.name}`,
             summary: `Upstream has ${upstreamCompare.aheadBy} commit(s) and the fork has ${forkCompare.aheadBy} custom commit(s). Review whether upstream should be merged, ignored, or resolved in a draft PR.`,
             upstreamFrom: upstreamCompare.mergeBaseSha,
-          upstreamTo: upstreamCompare.headSha ?? `${Date.now()}`,
+            upstreamTo: upstreamCompare.headSha,
+            dedupKey,
             forkHeadAtCreation: forkCompare.headSha,
             mergeBaseAtCreation:
               upstreamCompare.mergeBaseSha ?? forkCompare.mergeBaseSha,
@@ -306,6 +351,7 @@ const refreshOwnedSpoon = async (
           decision: 'thread_created',
         });
       }
+    }
     return {
       success: true,
       status,
@@ -408,6 +454,16 @@ export const syncForkWithUpstream = action({
       const message = error instanceof Error ? error.message : String(error);
       const conflict = message.toLowerCase().includes('conflict');
       if (conflict) {
+        const dedupKey = maintenanceDedupKey({
+          mergeBaseSha: state.mergeBaseSha ?? spoon.lastMergeBaseCommit,
+          headSha: state.upstreamHeadSha ?? spoon.lastUpstreamCommit,
+        });
+        if (!dedupKey) {
+          console.warn(
+            'Skipping maintenance thread: upstream head SHA unresolvable for spoon',
+            spoonId,
+          );
+        } else {
           const threadId = await ctx.runMutation(
             internal.threads.createMaintenanceThread,
             {
@@ -416,10 +472,8 @@ export const syncForkWithUpstream = action({
               source: 'merge_conflict',
               title: `Resolve upstream sync conflict for ${spoon.name}`,
               summary: `GitHub reported a conflict while syncing upstream into this fork: ${message}`,
-            upstreamTo:
+              upstreamTo: state.upstreamHeadSha ?? spoon.lastUpstreamCommit,
-              state.upstreamHeadSha ??
+              dedupKey,
-              spoon.lastUpstreamCommit ??
-              `${Date.now()}`,
               forkHeadAtCreation: state.forkHeadSha ?? spoon.lastForkCommit,
               mergeBaseAtCreation:
                 state.mergeBaseSha ?? spoon.lastMergeBaseCommit,
@@ -433,6 +487,7 @@ export const syncForkWithUpstream = action({
             decision: 'thread_created',
           });
         }
+      }
       await ctx.runMutation(internal.syncRuns.patchInternal, {
         syncRunId,
         status: conflict ? 'conflict' : 'failed',