fix(definitions): F05 定义库保存原子化并引入 revision 冲突检测

- FormulaDefinition 增加 revision 字段（迁移 0005）
- 保存接口在单事务内锁定用户所属行序列化并发：配额（50/数据集）检查与写入原子化，
  不再可能产生第 51 条；唯一约束竞争返回 409
- 同名更新必须携带匹配的 revision，两个窗口不再相互静默覆盖；
  GET 列表返回当前 revision；保存增加 30/小时限流
- 审计与定义变更（保存/删除）同一事务提交，审计失败一并回滚
- 前端保存同名定义时携带已知 revision，并明示“同名覆盖”行为
- 测试：revision 边界（缺失/过期/正确/再次过期）、配额拒绝与释放、
  审计失败回滚；PostgreSQL 并发配额用例独立门禁（本机 SQLite 跳过）

finance/formula_views.py

@@ -3,14 +3,17 @@ from pathlib import Path
 
 import httpx
 from django.conf import settings
+from django.db import IntegrityError, transaction
 from django.http import FileResponse, JsonResponse
 from django.utils import timezone
 
 from .analysis import METRICS, context, dimensions
 from .formula_columns import available_metrics, ensure_available_metrics, validate_column
-from .models import FormulaDefinition, FormulaExport
+from .models import FormulaDefinition, FormulaExport, Membership
 from .views import APIError, audit, body, dataset, endpoint, limit
 
+MAX_DEFINITIONS_PER_DATASET = 50
+
 
 def design_column(messages, ds, ctx):
     if not (settings.AI_ENABLED and settings.OPENAI_API_KEY and settings.OPENAI_MODEL):
@@ -198,6 +201,7 @@ def formula_definitions(request, dataset_id):
                     {
                         "id": str(item.pk),
                         "definition": item.definition,
+                        "revision": item.revision,
                         "updated_at": item.updated_at.isoformat(),
                     }
                     for item in items
@@ -205,28 +209,52 @@ def formula_definitions(request, dataset_id):
             }
         )
 
-    definition = validate_column(body(request).get("definition"))
+    data = body(request)
+    definition = validate_column(data.get("definition"))
     try:
         ensure_available_metrics(ds, definition)
     except ValueError as exc:
         raise APIError(str(exc)) from exc
     normalized_name = definition["name"].strip().casefold()
-    existing = FormulaDefinition.objects.filter(
-        dataset=ds, user=request.user, normalized_name=normalized_name
-    ).first()
-    if not existing and FormulaDefinition.objects.filter(dataset=ds, user=request.user).count() >= 50:
-        raise APIError("每个数据集最多保存 50 个公式定义")
-    item, created = FormulaDefinition.objects.update_or_create(
-        dataset=ds,
-        user=request.user,
-        normalized_name=normalized_name,
-        defaults={"definition": definition},
-    )
-    audit(request, "formula_definition.save", item.pk, {"dataset": str(ds.pk), "name": definition["name"]})
+    limit(f"formula-definition:{request.user.pk}", 30, 3600)
+    with transaction.atomic():
+        # 锁定稳定的用户所属行序列化同一用户的并发保存，使配额检查与写入原子化。
+        Membership.objects.select_for_update().get(pk=request.member.pk)
+        existing = (
+            FormulaDefinition.objects.select_for_update()
+            .filter(dataset=ds, user=request.user, normalized_name=normalized_name)
+            .first()
+        )
+        if existing:
+            # 同名更新按 revision 做乐观并发控制，避免两个窗口相互静默覆盖。
+            if data.get("revision") != existing.revision:
+                raise APIError("定义已在其他窗口更新，请刷新后重试", 409)
+            existing.definition, existing.revision = definition, existing.revision + 1
+            existing.save(update_fields=["definition", "revision", "updated_at"])
+            item, created = existing, False
+        else:
+            if (
+                FormulaDefinition.objects.filter(dataset=ds, user=request.user).count()
+                >= MAX_DEFINITIONS_PER_DATASET
+            ):
+                raise APIError(f"每个数据集最多保存 {MAX_DEFINITIONS_PER_DATASET} 个公式定义")
+            try:
+                item = FormulaDefinition.objects.create(
+                    dataset=ds,
+                    user=request.user,
+                    normalized_name=normalized_name,
+                    definition=definition,
+                )
+            except IntegrityError as exc:
+                raise APIError("定义保存发生并发冲突，请重试", 409) from exc
+            created = True
+        # 审计与定义变更在同一事务内提交；审计失败时变更一并回滚。
+        audit(request, "formula_definition.save", item.pk, {"dataset": str(ds.pk), "name": definition["name"]})
     return JsonResponse(
         {
             "id": str(item.pk),
             "definition": item.definition,
+            "revision": item.revision,
             "updated_at": item.updated_at.isoformat(),
         },
         status=201 if created else 200,
@@ -242,8 +270,9 @@ def formula_definition_delete(request, dataset_id, definition_id):
     if not item:
         raise APIError("公式定义不存在", 404)
     name = item.definition.get("name", "")
-    audit(request, "formula_definition.delete", item.pk, {"dataset": str(ds.pk), "name": name})
-    item.delete()
+    with transaction.atomic():
+        item.delete()
+        audit(request, "formula_definition.delete", item.pk, {"dataset": str(ds.pk), "name": name})
     return JsonResponse({"deleted": True})
 
 

finance/migrations/0005_formuladefinition_revision.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.2.17 on 2026-09-25 17:30
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('finance', '0004_formuladefinition'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='formuladefinition',
+            name='revision',
+            field=models.PositiveIntegerField(default=1),
+        ),
+    ]

finance/models.py

@@ -121,6 +121,7 @@ class FormulaDefinition(models.Model):
     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
     normalized_name = models.CharField(max_length=320)
     definition = models.JSONField()
+    revision = models.PositiveIntegerField(default=1)
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)