H-60: harden Captain migration rollback and concurrency (#10)

Co-authored-by: Rogee <rogee@ipao.vip>

backend/internal/service/captain_binding_atomicity_test.go

@@ -3,13 +3,18 @@ package service
 import (
 	"context"
 	"errors"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/gochat/gochat/internal/model"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"gorm.io/driver/sqlite"
+	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
 	"gorm.io/gorm/logger"
 )
@@ -42,31 +47,74 @@ func TestWidgetConversationRollsBackCaptainBindingOnCreateFailure(t *testing.T)
 }
 
 func TestEnsureCaptainAgentBotBindingConcurrentCallsStayUnique(t *testing.T) {
-	db, err := gorm.Open(sqlite.Open("file:"+t.Name()+"?mode=memory&cache=shared"), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
+	if os.Getenv("GOCHAT_TEST_DB") == "sqlite" {
+		t.Skip("requires PostgreSQL conflict handling")
+	}
+	dsn := os.Getenv("GOCHAT_TEST_DB_URL")
+	if dsn == "" {
+		dsn = "host=localhost port=5432 user=postgres password=postgres dbname=gochat_test sslmode=disable"
+	}
+	admin, err := gorm.Open(postgres.Open(dsn), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
+	require.NoError(t, err)
+	schema := fmt.Sprintf("captain_binding_%d", time.Now().UnixNano())
+	require.NoError(t, admin.Exec("CREATE SCHEMA "+schema).Error)
+	t.Cleanup(func() {
+		_ = admin.Exec("DROP SCHEMA " + schema + " CASCADE").Error
+		if sqlDB, dbErr := admin.DB(); dbErr == nil {
+			_ = sqlDB.Close()
+		}
+	})
+	if strings.HasPrefix(dsn, "postgres://") || strings.HasPrefix(dsn, "postgresql://") {
+		dsnURL, parseErr := url.Parse(dsn)
+		require.NoError(t, parseErr)
+		query := dsnURL.Query()
+		query.Set("search_path", schema)
+		dsnURL.RawQuery = query.Encode()
+		dsn = dsnURL.String()
+	} else {
+		dsn += " search_path=" + schema
+	}
+	db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{
+		Logger:                                   logger.Default.LogMode(logger.Silent),
+		DisableForeignKeyConstraintWhenMigrating: true,
+	})
 	require.NoError(t, err)
 	require.NoError(t, db.AutoMigrate(&model.CaptainAssistant{}, &model.AgentBot{}, &model.AgentBotInbox{}))
 	sqlDB, err := db.DB()
 	require.NoError(t, err)
-	sqlDB.SetMaxOpenConns(1)
+	const calls = 8
+	sqlDB.SetMaxOpenConns(calls)
 	t.Cleanup(func() { _ = sqlDB.Close() })
 	assistant := &model.CaptainAssistant{AccountID: 1, Name: "Concurrent", Status: model.AssistantStatusActive}
 	require.NoError(t, db.Create(assistant).Error)
 
-	const calls = 8
 	errs := make(chan error, calls)
 	ids := make(chan uint, calls)
+	ready := make(chan struct{}, calls)
+	start := make(chan struct{})
 	var wg sync.WaitGroup
 	for range calls {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			bot, err := ensureCaptainAgentBotBinding(context.Background(), db, assistant, 42)
+			var bot *model.AgentBot
+			err := db.Transaction(func(tx *gorm.DB) error {
+				ready <- struct{}{}
+				<-start
+				var bindErr error
+				bot, bindErr = ensureCaptainAgentBotBinding(context.Background(), tx, assistant, 42)
+				return bindErr
+			})
 			errs <- err
 			if bot != nil {
 				ids <- bot.ID
 			}
 		}()
 	}
+	for range calls {
+		<-ready
+	}
+	close(start)
 	wg.Wait()
 	close(errs)
 	close(ids)