fix: serialize repository refreshes and recover stale downloads

src/core/Repository.ts

@@ -1,4 +1,5 @@
 import storage from "./storage";
+import { randomUUID } from "crypto";
 import { RepositoryStatus } from "./types";
 import { Readable } from "stream";
 import * as sha1 from "crypto-js/sha1";
@@ -298,11 +299,70 @@ export default class Repository {
     return true;
   }
 
-  /**
-   * Update the repository if a new commit exists
-   *
-   * @returns void
-   */
+  private refreshToken?: string;
+
+  private refreshFilter() {
+    return this.refreshToken ? {
+      refreshToken: this.refreshToken,
+      refreshUntil: { $gt: new Date() },
+      status: this.model.status,
+      statusDate: this.model.statusDate || { $exists: false },
+      "githubAccess.revision": this.model.githubAccess?.revision || { $exists: false },
+    } : {};
+  }
+
+  private checkRefreshWrite(result: { matchedCount: number }) {
+    if (this.refreshToken && !result.matchedCount) {
+      throw new AnonymousError("invalid_status", { httpStatus: 409 });
+    }
+  }
+
+  /** Serialize dashboard refreshes across server processes without hiding a ready snapshot. */
+  async refresh() {
+    this.assertNotArchived();
+    if (!isConnected) return this.updateIfNeeded({ force: true });
+    const token = randomUUID();
+    const now = new Date();
+    const claimed = await AnonymizedRepositoryModel.updateOne({
+      _id: this.model._id,
+      status: this.model.status,
+      statusDate: this.model.statusDate || { $exists: false },
+      "githubAccess.revision": this.model.githubAccess?.revision || { $exists: false },
+      $or: [{ refreshUntil: { $exists: false } }, { refreshUntil: { $lte: now } }],
+    }, { $set: { refreshToken: token, refreshUntil: new Date(now.getTime() + 5 * 60_000) } }).exec();
+    if (!claimed.matchedCount) throw new AnonymousError("invalid_status", { httpStatus: 409 });
+    this.refreshToken = token;
+    try {
+      // An old timestamp can still belong to a live worker. Reusing its job ID
+      // would discard the replacement and cancel the old worker's generation.
+      const job = await downloadQueue.getJob(`repo-${this.repoId}`);
+      if (job) {
+        const state = await job.getState();
+        if (state !== "completed" && state !== "failed") {
+          throw new AnonymousError("invalid_status", { httpStatus: 409 });
+        }
+        await job.remove();
+      }
+      await this.updateIfNeeded({ force: true });
+    } catch (error) {
+      if (this.status === RepositoryStatus.PREPARING) {
+        // A failed reset/enqueue must remain retryable, even if the lease
+        // expired. Never change a replacement lease or a concurrent removal.
+        await AnonymizedRepositoryModel.updateOne({
+          _id: this.model._id, refreshToken: token,
+          status: RepositoryStatus.PREPARING, statusDate: this.model.statusDate,
+        }, { $set: { status: RepositoryStatus.ERROR, statusDate: new Date(), statusMessage: "preparation_interrupted" } }).exec();
+      }
+      throw error;
+    } finally {
+      this.refreshToken = undefined;
+      // Only this lease may be released, including after a failed GitHub lookup.
+      await AnonymizedRepositoryModel.updateOne({ _id: this.model._id, refreshToken: token },
+        { $unset: { refreshToken: 1, refreshUntil: 1 } }).exec();
+    }
+  }
+
+  /** Update the repository if a new commit exists. */
   async updateIfNeeded(opt?: { force: boolean }): Promise<void> {
     this.assertNotArchived();
     if (
@@ -311,7 +371,6 @@ export default class Repository {
       this._model.options.expirationDate
     ) {
       if (this._model.options.expirationDate <= new Date()) {
-        this._model.status = RepositoryStatus.EXPIRED;
         await this.expire();
         throw new AnonymousError("repository_expired", {
           object: this,
@@ -345,10 +404,11 @@ export default class Repository {
         if (this.model.source.repositoryName !== ghRepo.fullName) {
           this.model.source.repositoryName = ghRepo.fullName;
           if (isConnected) {
-            await AnonymizedRepositoryModel.updateOne(
-              { _id: this._model._id },
+            const result = await AnonymizedRepositoryModel.updateOne(
+              { _id: this._model._id, ...this.refreshFilter() },
               { $set: { "source.repositoryName": ghRepo.fullName } }
             ).exec();
+            this.checkRefreshWrite(result);
           }
         }
         const branches = await ghRepo.branches({
@@ -401,19 +461,32 @@ export default class Repository {
           commit: newCommit,
         });
 
+        const statusDate = new Date();
         if (isConnected) {
-          await AnonymizedRepositoryModel.updateOne(
-            { _id: this._model._id },
+          const result = await AnonymizedRepositoryModel.updateOne(
+            { _id: this._model._id, ...this.refreshFilter() },
             {
               $set: {
                 "source.commit": newCommit,
                 "source.commitDate": this._model.source.commitDate,
                 anonymizeDate: this._model.anonymizeDate,
+                status: RepositoryStatus.PREPARING,
+                statusDate,
+                statusMessage: null,
               },
             }
           ).exec();
+          this.checkRefreshWrite(result);
+        }
+        this.model.status = RepositoryStatus.PREPARING;
+        this.model.statusDate = statusDate;
+        this.model.statusMessage = undefined;
+        await this.resetSate();
+        if (isConnected && this.refreshToken) {
+          // Removal or expiry may have started while deleting the old cache.
+          const current = await AnonymizedRepositoryModel.exists({ _id: this.model._id, ...this.refreshFilter() });
+          if (!current) throw new AnonymousError("invalid_status", { httpStatus: 409 });
         }
-        await this.resetSate(RepositoryStatus.PREPARING);
         await downloadQueue.add(this.repoId, { repoId: this.repoId }, {
           jobId: `repo-${this.repoId}`,
           attempts: 3,
@@ -481,6 +554,7 @@ export default class Repository {
       const result = await AnonymizedRepositoryModel.updateOne(
         {
           _id: this._model._id,
+          ...this.refreshFilter(),
           ...(this.protectLifecycle ? {
             status: { $nin: [RepositoryStatus.ARCHIVED, RepositoryStatus.REMOVING, RepositoryStatus.REMOVED,
               RepositoryStatus.EXPIRING, RepositoryStatus.EXPIRED] },
@@ -490,6 +564,7 @@ export default class Repository {
         },
         { $set: { status, statusDate, statusMessage, ...(publishedAt ? { publishedAt } : {}) } }
       ).exec();
+      this.checkRefreshWrite(result);
       if (this.protectLifecycle && result.matchedCount === 0) {
         throw new AnonymousError("repository_job_cancelled", { httpStatus: 410 });
       }

src/core/model/anonymizedRepositories/anonymizedRepositories.schema.ts

@@ -11,6 +11,8 @@ const AnonymizedRepositorySchema = new Schema({
     default: "preparing",
   },
   statusDate: Date,
+  refreshToken: { type: String, select: false },
+  refreshUntil: { type: Date, select: false },
   archivedAt: Date,
   archiveReason: String,
   archiveCachePending: Boolean,

src/server/routes/repository-private.ts

@@ -132,14 +132,15 @@ router.post(
       if (
         repo.status == RepositoryStatus.PREPARING ||
         repo.status == RepositoryStatus.QUEUE ||
-        repo.status == RepositoryStatus.DOWNLOAD ||
+        (repo.status == RepositoryStatus.DOWNLOAD &&
+          repo.model.statusDate > new Date(Date.now() - 5 * 60_000)) ||
         repo.status == RepositoryStatus.REMOVING ||
         repo.status == RepositoryStatus.EXPIRING
       ) {
         throw new AnonymousError("invalid_status", { httpStatus: 409 });
       }
 
-      await repo.updateIfNeeded({ force: true });
+      await repo.refresh();
       res.json({ status: repo.status });
     } catch (error) {
       handleError(error, res, req);