fix(conversations): 修复会话标识与解决后跳转

backend/internal/repository/conversation_repo.go

@@ -272,17 +272,29 @@ func (r *ConversationRepo) Search(ctx context.Context, accountID uint, query str
 
 // Create inserts a new conversation.
 func (r *ConversationRepo) Create(ctx context.Context, conversation *model.Conversation) error {
-	if conversation.DisplayID == nil || *conversation.DisplayID == 0 {
+	if conversation.DisplayID != nil && *conversation.DisplayID != 0 {
+		return r.db.WithContext(ctx).Create(conversation).Error
+	}
+
+	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		// PostgreSQL needs serialization because MAX(display_id)+1 is otherwise
+		// racy when a channel imports several conversations concurrently.
+		if tx.Dialector != nil && tx.Dialector.Name() == "postgres" {
+			if err := tx.Exec("SELECT pg_advisory_xact_lock(?)", int64(conversation.AccountID)).Error; err != nil {
+				return err
+			}
+		}
+
 		var next uint
-		if err := r.db.WithContext(ctx).Model(&model.Conversation{}).
+		if err := tx.Model(&model.Conversation{}).
 			Select("COALESCE(MAX(display_id), 0) + 1").
 			Where("account_id = ?", conversation.AccountID).
 			Scan(&next).Error; err != nil {
 			return err
 		}
 		conversation.DisplayID = &next
-	}
-	return r.db.WithContext(ctx).Create(conversation).Error
+		return tx.Create(conversation).Error
+	})
 }
 
 // Update modifies an existing conversation.

backend/internal/repository/coverage2_test.go

@@ -90,6 +90,21 @@ func TestConversationRepo_FindByAccountAndDisplayIDOrID_PrefersLegacyNullDisplay
 	assert.Nil(t, found.DisplayID)
 }
 
+func TestConversationRepo_Create_AssignsDistinctSequentialDisplayIDs(t *testing.T) {
+	db := setupTestDB(t)
+	repo := NewConversationRepo(db)
+	ctx := context.Background()
+	account, inbox, contact := createConvAccount(t, db)
+
+	first := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: "open", ChannelType: "web_widget", Channel: "web_widget"}
+	second := &model.Conversation{AccountID: account.ID, InboxID: inbox.ID, ContactID: contact.ID, Status: "open", ChannelType: "web_widget", Channel: "web_widget"}
+	require.NoError(t, repo.Create(ctx, first))
+	require.NoError(t, repo.Create(ctx, second))
+	require.NotNil(t, first.DisplayID)
+	require.NotNil(t, second.DisplayID)
+	assert.Equal(t, *first.DisplayID+1, *second.DisplayID)
+}
+
 func TestCov2_ConversationRepo_FindByContact(t *testing.T) {
 	db := setupTestDB(t)
 	repo := NewConversationRepo(db)

backend/migrations/000066_repair_conversation_display_ids.down.sql

@@ -0,0 +1,7 @@
+DROP INDEX IF EXISTS idx_conversations_account_display_id;
+CREATE INDEX idx_conversations_account_display_id
+    ON conversations(account_id, display_id)
+    WHERE deleted_at IS NULL;
+
+-- Repaired display IDs are intentionally retained: their previous duplicate
+-- values cannot be restored without reintroducing ambiguous conversation URLs.

backend/migrations/000066_repair_conversation_display_ids.up.sql

@@ -0,0 +1,57 @@
+-- Repair duplicate and missing account-scoped conversation display IDs before
+-- enforcing the Chatwoot routing invariant. Keep already-unique IDs stable so
+-- existing conversation URLs continue to resolve to the same records.
+WITH ranked AS (
+    SELECT
+        id,
+        account_id,
+        display_id,
+        ROW_NUMBER() OVER (
+            PARTITION BY account_id, display_id
+            ORDER BY id
+        ) AS duplicate_rank
+    FROM conversations
+    WHERE deleted_at IS NULL
+      AND display_id IS NOT NULL
+      AND display_id > 0
+),
+needs_repair AS (
+    SELECT id, account_id
+    FROM ranked
+    WHERE duplicate_rank > 1
+
+    UNION ALL
+
+    SELECT id, account_id
+    FROM conversations
+    WHERE deleted_at IS NULL
+      AND (display_id IS NULL OR display_id = 0)
+),
+account_max AS (
+    SELECT account_id, COALESCE(MAX(display_id), 0) AS max_display_id
+    FROM conversations
+    WHERE deleted_at IS NULL
+      AND display_id IS NOT NULL
+      AND display_id > 0
+    GROUP BY account_id
+),
+replacements AS (
+    SELECT
+        repair.id,
+        COALESCE(account_max.max_display_id, 0)
+            + ROW_NUMBER() OVER (
+                PARTITION BY repair.account_id
+                ORDER BY repair.id
+            ) AS display_id
+    FROM needs_repair AS repair
+    LEFT JOIN account_max ON account_max.account_id = repair.account_id
+)
+UPDATE conversations AS conversation
+SET display_id = replacements.display_id
+FROM replacements
+WHERE conversation.id = replacements.id;
+
+DROP INDEX IF EXISTS idx_conversations_account_display_id;
+CREATE UNIQUE INDEX idx_conversations_account_display_id
+    ON conversations(account_id, display_id)
+    WHERE deleted_at IS NULL;