Merge pull request #25958 from overleaf/bg-history-redis-check-persisted-version-on-update

prevent setPersistedVersion from setting an out of bounds version

GitOrigin-RevId: 9561b7b96399bed901db5c2ac20a0cdbf4c67395

services/history-v1/storage/lib/chunk_store/redis.js

@@ -501,6 +501,11 @@ rclient.defineCommand('set_persisted_version', {
       return 'too_low'
     end
 
+    -- Refuse to set a persisted version that is higher than the head version
+    if newPersistedVersion > headVersion then
+      return 'too_high'
+    end
+
     -- Set the persisted version
     redis.call('SET', persistedVersionKey, newPersistedVersion)
 
@@ -541,6 +546,13 @@ async function setPersistedVersion(projectId, persistedVersion) {
       status,
     })
 
+    if (status === 'too_high') {
+      throw new VersionOutOfBoundsError(
+        'Persisted version cannot be higher than head version',
+        { projectId, persistedVersion }
+      )
+    }
+
     return status
   } catch (err) {
     metrics.inc('chunk_store.redis.set_persisted_version', 1, {

services/history-v1/test/acceptance/js/storage/chunk_store_redis_backend.test.js

@@ -714,10 +714,20 @@ describe('chunk buffer Redis backend', function () {
       })
 
       it('should set the persisted version', async function () {
-        await redisBackend.setPersistedVersion(projectId, 3)
+        const status = await redisBackend.setPersistedVersion(projectId, 3)
+        expect(status).to.equal('ok')
         const state = await redisBackend.getState(projectId)
         expect(state.persistedVersion).to.equal(3)
       })
+
+      it('should refuse to set a persisted version greater than the head version', async function () {
+        await expect(
+          redisBackend.setPersistedVersion(projectId, 10)
+        ).to.be.rejectedWith(VersionOutOfBoundsError)
+        // Ensure persisted version remains unchanged
+        const state = await redisBackend.getState(projectId)
+        expect(state.persistedVersion).to.be.null
+      })
     })
 
     describe('when the persisted version is set', function () {
@@ -730,13 +740,24 @@ describe('chunk buffer Redis backend', function () {
       })
 
       it('should set the persisted version', async function () {
-        await redisBackend.setPersistedVersion(projectId, 5)
+        const status = await redisBackend.setPersistedVersion(projectId, 5)
+        expect(status).to.equal('ok')
         const state = await redisBackend.getState(projectId)
         expect(state.persistedVersion).to.equal(5)
       })
 
       it('should not decrease the persisted version', async function () {
-        await redisBackend.setPersistedVersion(projectId, 2)
+        const status = await redisBackend.setPersistedVersion(projectId, 2)
+        expect(status).to.equal('too_low')
+        const state = await redisBackend.getState(projectId)
+        expect(state.persistedVersion).to.equal(3)
+      })
+
+      it('should refuse to set a persisted version greater than the head version', async function () {
+        await expect(
+          redisBackend.setPersistedVersion(projectId, 10)
+        ).to.be.rejectedWith(VersionOutOfBoundsError)
+        // Ensure persisted version remains unchanged
         const state = await redisBackend.getState(projectId)
         expect(state.persistedVersion).to.equal(3)
       })