fix(db): keep filter type and cohort ids when loading saved reports

packages/db/src/services/reports.service.test.ts

@@ -5,7 +5,7 @@
  */
 import type { IChartEventFilter, IChartEventItem } from '@openpanel/validation';
 import { describe, expect, it } from 'vitest';
-import { mergeGlobalFilters } from './reports.service';
+import { mergeGlobalFilters, transformFilter } from './reports.service';
 
 const globalFilter: IChartEventFilter = {
   id: 'g1',
@@ -64,3 +64,48 @@ describe('mergeGlobalFilters', () => {
     expect(eventSeries.filters).toEqual([eventFilter]);
   });
 });
+
+describe('transformFilter', () => {
+  it('keeps the cast type so a saved date filter stays a date filter', () => {
+    const result = transformFilter(
+      {
+        id: 'f1',
+        name: 'profile.properties.subscription_expire',
+        operator: 'gte',
+        value: ['2026-09-27'],
+        type: 'date',
+      },
+      0,
+    );
+    expect(result.type).toBe('date');
+  });
+
+  it('keeps cohort ids', () => {
+    const result = transformFilter(
+      {
+        id: 'f1',
+        name: 'cohort',
+        operator: 'inCohort',
+        value: [],
+        cohortIds: ['c1', 'c2'],
+        cohortId: 'c0',
+      },
+      0,
+    );
+    expect(result.cohortIds).toEqual(['c1', 'c2']);
+    expect(result.cohortId).toBe('c0');
+  });
+
+  it('leaves the optional fields off legacy filters', () => {
+    const result = transformFilter(
+      { name: 'path', operator: 'is', value: '/pricing' as never },
+      1,
+    );
+    expect(result).toEqual({
+      id: 'B',
+      name: 'path',
+      operator: 'is',
+      value: ['/pricing'],
+    });
+  });
+});

packages/db/src/services/reports.service.ts

@@ -50,6 +50,11 @@ export function transformFilter(
     operator: filter.operator ?? 'is',
     value:
       typeof filter.value === 'string' ? [filter.value] : (filter.value ?? []),
+    // Pass the optional fields through so a saved report keeps its cast type
+    // and cohort selection after it is reloaded.
+    ...(filter.type ? { type: filter.type } : {}),
+    ...(filter.cohortId ? { cohortId: filter.cohortId } : {}),
+    ...(filter.cohortIds ? { cohortIds: filter.cohortIds } : {}),
   };
 }