Fix a panic related to batch GC

nomad/state/state_store.go

@@ -1126,6 +1126,9 @@ func (s *StateStore) deleteJobVersions(index uint64, job *structs.Job, txn *memd
 		return err
 	}
 
+	// Put them into a slice so there are no safety concerns while actually
+	// performing the deletes
+	jobs := []*structs.Job{}
 	for {
 		raw := iter.Next()
 		if raw == nil {
@@ -1138,7 +1141,12 @@ func (s *StateStore) deleteJobVersions(index uint64, job *structs.Job, txn *memd
 			continue
 		}
 
-		if _, err = txn.DeleteAll("job_version", "id", j.Namespace, j.ID, j.Version); err != nil {
+		jobs = append(jobs, j)
+	}
+
+	// Do the deletes
+	for _, j := range jobs {
+		if err := txn.Delete("job_version", j); err != nil {
 			return fmt.Errorf("deleting job versions failed: %v", err)
 		}
 	}

nomad/state/state_store_test.go

@@ -1661,6 +1661,70 @@ func TestStateStore_DeleteJob_Job(t *testing.T) {
 	}
 }
 
+func TestStateStore_DeleteJobTxn_BatchDeletes(t *testing.T) {
+	state := testStateStore(t)
+
+	const testJobCount = 10
+	const jobVersionCount = 4
+
+	jobs := make([]*structs.Job, testJobCount)
+	for i := 0; i < testJobCount; i++ {
+		job := mock.BatchJob()
+
+		err := state.UpsertJob(uint64(100+i), job)
+		require.NoError(t, err)
+
+		jobs[i] = job
+
+		// create some versions
+		for vi := 1; vi < jobVersionCount; vi++ {
+			job := job.Copy()
+			job.TaskGroups[0].Tasks[0].Env = map[string]string{
+				"Version": fmt.Sprintf("%d", vi),
+			}
+
+			require.NoError(t, state.UpsertJob(uint64(100+i+vi*10), job))
+		}
+	}
+
+	ws := memdb.NewWatchSet()
+
+	// sanity check that jobs are present in DB
+	job, err := state.JobByID(ws, jobs[0].Namespace, jobs[0].ID)
+	require.NoError(t, err)
+	require.Equal(t, jobs[0].ID, job.ID)
+
+	jobVersions, err := state.JobVersionsByID(ws, jobs[0].Namespace, jobs[0].ID)
+	require.NoError(t, err)
+	require.Equal(t, jobVersionCount, len(jobVersions))
+
+	// actually delete
+	const deletionIndex = uint64(10001)
+	err = state.WithWriteTransaction(func(txn Txn) error {
+		for i, job := range jobs {
+			err := state.DeleteJobTxn(deletionIndex, job.Namespace, job.ID, txn)
+			require.NoError(t, err, "failed at %d %e", i, err)
+		}
+		return nil
+	})
+	assert.NoError(t, err)
+
+	assert.True(t, watchFired(ws))
+
+	ws = memdb.NewWatchSet()
+	out, err := state.JobByID(ws, jobs[0].Namespace, jobs[0].ID)
+	require.NoError(t, err)
+	require.Nil(t, out)
+
+	jobVersions, err = state.JobVersionsByID(ws, jobs[0].Namespace, jobs[0].ID)
+	require.NoError(t, err)
+	require.Empty(t, jobVersions)
+
+	index, err := state.Index("jobs")
+	require.NoError(t, err)
+	require.Equal(t, deletionIndex, index)
+}
+
 func TestStateStore_DeleteJob_MultipleVersions(t *testing.T) {
 	state := testStateStore(t)
 	assert := assert.New(t)