refactor(task): enhance UpdateWithStatus for CAS updates and add integration tests

- Updated UpdateWithStatus method to use Model().Select("*").Updates() for conditional updates, preventing GORM's INSERT fallback.
- Introduced comprehensive integration tests for UpdateWithStatus, covering scenarios for winning and losing CAS updates, as well as concurrent updates.
- Added task_cas_test.go to validate the new behavior and ensure data integrity during concurrent state transitions.

model/midjourney.go

@@ -160,8 +160,10 @@ func (midjourney *Midjourney) Update() error {
 // UpdateWithStatus performs a conditional UPDATE guarded by fromStatus (CAS).
 // UpdateWithStatus performs a conditional UPDATE guarded by fromStatus (CAS).
 // Returns (true, nil) if this caller won the update, (false, nil) if
 // Returns (true, nil) if this caller won the update, (false, nil) if
 // another process already moved the task out of fromStatus.
 // another process already moved the task out of fromStatus.
+// UpdateWithStatus performs a conditional UPDATE guarded by fromStatus (CAS).
+// Uses Model().Select("*").Updates() to avoid GORM Save()'s INSERT fallback.
 func (midjourney *Midjourney) UpdateWithStatus(fromStatus string) (bool, error) {
 func (midjourney *Midjourney) UpdateWithStatus(fromStatus string) (bool, error) {
-	result := DB.Where("status = ?", fromStatus).Save(midjourney)
+	result := DB.Model(midjourney).Where("status = ?", fromStatus).Select("*").Updates(midjourney)
 	if result.Error != nil {
 	if result.Error != nil {
 		return false, result.Error
 		return false, result.Error
 	}
 	}

model/task.go

@@ -388,8 +388,12 @@ func (Task *Task) Update() error {
 // UpdateWithStatus performs a conditional UPDATE guarded by fromStatus (CAS).
 // UpdateWithStatus performs a conditional UPDATE guarded by fromStatus (CAS).
 // Returns (true, nil) if this caller won the update, (false, nil) if
 // Returns (true, nil) if this caller won the update, (false, nil) if
 // another process already moved the task out of fromStatus.
 // another process already moved the task out of fromStatus.
+//
+// Uses Model().Select("*").Updates() instead of Save() because GORM's Save
+// falls back to INSERT ON CONFLICT when the WHERE-guarded UPDATE matches
+// zero rows, which silently bypasses the CAS guard.
 func (t *Task) UpdateWithStatus(fromStatus TaskStatus) (bool, error) {
 func (t *Task) UpdateWithStatus(fromStatus TaskStatus) (bool, error) {
-	result := DB.Where("status = ?", fromStatus).Save(t)
+	result := DB.Model(t).Where("status = ?", fromStatus).Select("*").Updates(t)
 	if result.Error != nil {
 	if result.Error != nil {
 		return false, result.Error
 		return false, result.Error
 	}
 	}

model/task_cas_test.go

+package model
+
+import (
+	"encoding/json"
+	"os"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/QuantumNous/new-api/common"
+	"github.com/glebarez/sqlite"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/gorm"
+)
+
+func TestMain(m *testing.M) {
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		panic("failed to open test db: " + err.Error())
+	}
+	DB = db
+	LOG_DB = db
+
+	common.UsingSQLite = true
+	common.RedisEnabled = false
+	common.BatchUpdateEnabled = false
+	common.LogConsumeEnabled = true
+
+	sqlDB, err := db.DB()
+	if err != nil {
+		panic("failed to get sql.DB: " + err.Error())
+	}
+	sqlDB.SetMaxOpenConns(1)
+
+	if err := db.AutoMigrate(&Task{}, &User{}, &Token{}, &Log{}, &Channel{}); err != nil {
+		panic("failed to migrate: " + err.Error())
+	}
+
+	os.Exit(m.Run())
+}
+
+func truncateTables(t *testing.T) {
+	t.Helper()
+	t.Cleanup(func() {
+		DB.Exec("DELETE FROM tasks")
+		DB.Exec("DELETE FROM users")
+		DB.Exec("DELETE FROM tokens")
+		DB.Exec("DELETE FROM logs")
+		DB.Exec("DELETE FROM channels")
+	})
+}
+
+func insertTask(t *testing.T, task *Task) {
+	t.Helper()
+	task.CreatedAt = time.Now().Unix()
+	task.UpdatedAt = time.Now().Unix()
+	require.NoError(t, DB.Create(task).Error)
+}
+
+// ---------------------------------------------------------------------------
+// Snapshot / Equal — pure logic tests (no DB)
+// ---------------------------------------------------------------------------
+
+func TestSnapshotEqual_Same(t *testing.T) {
+	s := taskSnapshot{
+		Status:     TaskStatusInProgress,
+		Progress:   "50%",
+		StartTime:  1000,
+		FinishTime: 0,
+		FailReason: "",
+		ResultURL:  "",
+		Data:       json.RawMessage(`{"key":"value"}`),
+	}
+	assert.True(t, s.Equal(s))
+}
+
+func TestSnapshotEqual_DifferentStatus(t *testing.T) {
+	a := taskSnapshot{Status: TaskStatusInProgress, Data: json.RawMessage(`{}`)}
+	b := taskSnapshot{Status: TaskStatusSuccess, Data: json.RawMessage(`{}`)}
+	assert.False(t, a.Equal(b))
+}
+
+func TestSnapshotEqual_DifferentProgress(t *testing.T) {
+	a := taskSnapshot{Status: TaskStatusInProgress, Progress: "30%", Data: json.RawMessage(`{}`)}
+	b := taskSnapshot{Status: TaskStatusInProgress, Progress: "60%", Data: json.RawMessage(`{}`)}
+	assert.False(t, a.Equal(b))
+}
+
+func TestSnapshotEqual_DifferentData(t *testing.T) {
+	a := taskSnapshot{Status: TaskStatusInProgress, Data: json.RawMessage(`{"a":1}`)}
+	b := taskSnapshot{Status: TaskStatusInProgress, Data: json.RawMessage(`{"a":2}`)}
+	assert.False(t, a.Equal(b))
+}
+
+func TestSnapshotEqual_NilVsEmpty(t *testing.T) {
+	a := taskSnapshot{Status: TaskStatusInProgress, Data: nil}
+	b := taskSnapshot{Status: TaskStatusInProgress, Data: json.RawMessage{}}
+	// bytes.Equal(nil, []byte{}) == true
+	assert.True(t, a.Equal(b))
+}
+
+func TestSnapshot_Roundtrip(t *testing.T) {
+	task := &Task{
+		Status:     TaskStatusInProgress,
+		Progress:   "42%",
+		StartTime:  1234,
+		FinishTime: 5678,
+		FailReason: "timeout",
+		PrivateData: TaskPrivateData{
+			ResultURL: "https://example.com/result.mp4",
+		},
+		Data: json.RawMessage(`{"model":"test-model"}`),
+	}
+	snap := task.Snapshot()
+	assert.Equal(t, task.Status, snap.Status)
+	assert.Equal(t, task.Progress, snap.Progress)
+	assert.Equal(t, task.StartTime, snap.StartTime)
+	assert.Equal(t, task.FinishTime, snap.FinishTime)
+	assert.Equal(t, task.FailReason, snap.FailReason)
+	assert.Equal(t, task.PrivateData.ResultURL, snap.ResultURL)
+	assert.JSONEq(t, string(task.Data), string(snap.Data))
+}
+
+// ---------------------------------------------------------------------------
+// UpdateWithStatus CAS — DB integration tests
+// ---------------------------------------------------------------------------
+
+func TestUpdateWithStatus_Win(t *testing.T) {
+	truncateTables(t)
+
+	task := &Task{
+		TaskID:   "task_cas_win",
+		Status:   TaskStatusInProgress,
+		Progress: "50%",
+		Data:     json.RawMessage(`{}`),
+	}
+	insertTask(t, task)
+
+	task.Status = TaskStatusSuccess
+	task.Progress = "100%"
+	won, err := task.UpdateWithStatus(TaskStatusInProgress)
+	require.NoError(t, err)
+	assert.True(t, won)
+
+	var reloaded Task
+	require.NoError(t, DB.First(&reloaded, task.ID).Error)
+	assert.EqualValues(t, TaskStatusSuccess, reloaded.Status)
+	assert.Equal(t, "100%", reloaded.Progress)
+}
+
+func TestUpdateWithStatus_Lose(t *testing.T) {
+	truncateTables(t)
+
+	task := &Task{
+		TaskID: "task_cas_lose",
+		Status: TaskStatusFailure,
+		Data:   json.RawMessage(`{}`),
+	}
+	insertTask(t, task)
+
+	task.Status = TaskStatusSuccess
+	won, err := task.UpdateWithStatus(TaskStatusInProgress) // wrong fromStatus
+	require.NoError(t, err)
+	assert.False(t, won)
+
+	var reloaded Task
+	require.NoError(t, DB.First(&reloaded, task.ID).Error)
+	assert.EqualValues(t, TaskStatusFailure, reloaded.Status) // unchanged
+}
+
+func TestUpdateWithStatus_ConcurrentWinner(t *testing.T) {
+	truncateTables(t)
+
+	task := &Task{
+		TaskID: "task_cas_race",
+		Status: TaskStatusInProgress,
+		Quota:  1000,
+		Data:   json.RawMessage(`{}`),
+	}
+	insertTask(t, task)
+
+	const goroutines = 5
+	wins := make([]bool, goroutines)
+	var wg sync.WaitGroup
+	wg.Add(goroutines)
+
+	for i := 0; i < goroutines; i++ {
+		go func(idx int) {
+			defer wg.Done()
+			t := &Task{}
+			*t = Task{
+				ID:       task.ID,
+				TaskID:   task.TaskID,
+				Status:   TaskStatusSuccess,
+				Progress: "100%",
+				Quota:    task.Quota,
+				Data:     json.RawMessage(`{}`),
+			}
+			t.CreatedAt = task.CreatedAt
+			t.UpdatedAt = time.Now().Unix()
+			won, err := t.UpdateWithStatus(TaskStatusInProgress)
+			if err == nil {
+				wins[idx] = won
+			}
+		}(i)
+	}
+	wg.Wait()
+
+	winCount := 0
+	for _, w := range wins {
+		if w {
+			winCount++
+		}
+	}
+	assert.Equal(t, 1, winCount, "exactly one goroutine should win the CAS")
+}