fix(shared): log db error in feature-toggle override read (#1286)

packages/shared/src/services/FeatureToggleService.spec.ts

@@ -28,6 +28,12 @@ jest.mock('../config/featureToggles', () => ({
     }),
 }))
 
+const mockWarnLog = jest.fn()
+jest.mock('../utils/general/log', () => ({
+    ...jest.requireActual<object>('../utils/general/log'),
+    warnLog: (...args: unknown[]) => mockWarnLog(...args),
+}))
+
 describe('FeatureToggleService', () => {
     let service: InstanceType<
         (typeof import('./FeatureToggleService'))['featureToggleService'] extends infer S
@@ -43,6 +49,7 @@ describe('FeatureToggleService', () => {
         delete process.env.FLAGS
         mockFindUnique.mockReset()
         mockUpsert.mockReset()
+        mockWarnLog.mockReset()
 
         const mod = await import('./FeatureToggleService')
         service = mod.featureToggleService as unknown as typeof service
@@ -87,14 +94,22 @@ describe('FeatureToggleService', () => {
             expect(result).toBeNull()
         })
 
-        it('returns null when db throws', async () => {
+        it('returns null and logs a warning when db throws', async () => {
             mockFindUnique.mockRejectedValue(new Error('DB connection failed'))
             const result = await (
                 service as unknown as {
                     getDbGlobalOverride(name: string): Promise<boolean | null>
                 }
             ).getDbGlobalOverride('DOWNLOAD_AUDIO')
             expect(result).toBeNull()
+            // #1286 B3: the DB failure must be surfaced, not swallowed silently.
+            expect(mockWarnLog).toHaveBeenCalledTimes(1)
+            expect(mockWarnLog).toHaveBeenCalledWith(
+                expect.objectContaining({
+                    error: expect.any(Error),
+                    data: { name: 'DOWNLOAD_AUDIO' },
+                }),
+            )
         })
     })
 

packages/shared/src/services/FeatureToggleService.ts

@@ -5,6 +5,7 @@ import type {
 } from '../types/featureToggle'
 import { getFeatureToggleConfig } from '../config/featureToggles'
 import { getPrismaClient } from '../utils/database/prismaClient'
+import { warnLog } from '../utils/general/log'
 
 /** Manages feature toggles with multi-layer provider support (database, environment). */
 class FeatureToggleService {
@@ -39,7 +40,16 @@ class FeatureToggleService {
                 select: { enabled: true },
             })
             return row?.enabled ?? null
-        } catch {
+        } catch (error) {
+            // Fail open to the environment/config fallback, but surface the
+            // failure: a swallowed-to-null DB error here was indistinguishable
+            // from "no override set", hiding a persistent outage (#1286 B3).
+            warnLog({
+                message:
+                    'Failed to read global feature toggle override; falling back to config default',
+                error,
+                data: { name },
+            })
             return null
         }
     }