fix image model alias compatibility

tests/unit/api-config/model-selection-alias.test.ts

@@ -0,0 +1,88 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const prismaMock = vi.hoisted(() => ({
+  userPreference: {
+    findUnique: vi.fn<(...args: unknown[]) => Promise<{ customModels: string; customProviders: string | null } | null>>(async () => null),
+  },
+}))
+
+vi.mock('@/lib/prisma', () => ({
+  prisma: prismaMock,
+}))
+
+import { resolveModelSelection } from '@/lib/api-config'
+
+const compatImageTemplate = {
+  version: 1 as const,
+  mediaType: 'image' as const,
+  mode: 'sync' as const,
+  create: {
+    method: 'POST' as const,
+    path: '/images/generations',
+    contentType: 'application/json' as const,
+    bodyTemplate: {
+      model: '{{model}}',
+      prompt: '{{prompt}}',
+    },
+  },
+  response: {
+    outputUrlPath: '$.data[0].url',
+    errorPath: '$.error.message',
+  },
+}
+
+describe('api-config image model alias resolution', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('matches a preview image model when the caller still uses the legacy model id', async () => {
+    prismaMock.userPreference.findUnique.mockResolvedValueOnce({
+      customProviders: null,
+      customModels: JSON.stringify([
+        {
+          modelId: 'gemini-3.1-flash-image-preview',
+          modelKey: 'openai-compatible:oa-1::gemini-3.1-flash-image-preview',
+          name: 'Nano Banana 2',
+          type: 'image',
+          provider: 'openai-compatible:oa-1',
+          compatMediaTemplate: compatImageTemplate,
+        },
+      ]),
+    })
+
+    const selection = await resolveModelSelection(
+      'user-1',
+      'openai-compatible:oa-1::gemini-3.1-flash-image',
+      'image',
+    )
+
+    expect(selection.modelId).toBe('gemini-3.1-flash-image-preview')
+    expect(selection.modelKey).toBe('openai-compatible:oa-1::gemini-3.1-flash-image-preview')
+  })
+
+  it('matches a legacy image model when the caller already uses the preview model id', async () => {
+    prismaMock.userPreference.findUnique.mockResolvedValueOnce({
+      customProviders: null,
+      customModels: JSON.stringify([
+        {
+          modelId: 'gemini-3.1-flash-image',
+          modelKey: 'openai-compatible:oa-1::gemini-3.1-flash-image',
+          name: 'Nano Banana 2',
+          type: 'image',
+          provider: 'openai-compatible:oa-1',
+          compatMediaTemplate: compatImageTemplate,
+        },
+      ]),
+    })
+
+    const selection = await resolveModelSelection(
+      'user-1',
+      'openai-compatible:oa-1::gemini-3.1-flash-image-preview',
+      'image',
+    )
+
+    expect(selection.modelId).toBe('gemini-3.1-flash-image')
+    expect(selection.modelKey).toBe('openai-compatible:oa-1::gemini-3.1-flash-image')
+  })
+})

tests/unit/generator-api.test.ts

@@ -118,7 +118,7 @@ describe('generator-api gateway routing', () => {
     expect(result).toEqual({ success: true, imageUrl: 'compat-template-image' })
   })
 
-  it('normalizes legacy openai-compatible gemini image model ids before template gateway call', async () => {
+  it('prefers the resolved openai-compatible image model id before trying aliases', async () => {
     resolveModelSelectionMock.mockResolvedValueOnce({
       provider: 'openai-compatible:oa-1',
       modelId: 'gemini-3.1-flash-image',
@@ -137,6 +137,35 @@ describe('generator-api gateway routing', () => {
     await generateImage('user-1', 'openai-compatible:oa-1::gemini-3.1-flash-image', 'draw hero')
 
     expect(generateImageViaOpenAICompatTemplateMock).toHaveBeenCalledWith(expect.objectContaining({
+      modelId: 'gemini-3.1-flash-image',
+    }))
+  })
+
+  it('retries openai-compatible image generation with a compatible alias after a model-id rejection', async () => {
+    resolveModelSelectionMock.mockResolvedValueOnce({
+      provider: 'openai-compatible:oa-1',
+      modelId: 'gemini-3.1-flash-image',
+      modelKey: 'openai-compatible:oa-1::gemini-3.1-flash-image',
+      mediaType: 'image',
+      compatMediaTemplate: {
+        version: 1,
+        mediaType: 'image',
+        mode: 'sync',
+        create: { method: 'POST', path: '/v1/images/generations' },
+        response: { outputUrlPath: '$.data[0].url' },
+      },
+    })
+    resolveModelGatewayRouteMock.mockReturnValueOnce('openai-compat')
+    generateImageViaOpenAICompatTemplateMock
+      .mockRejectedValueOnce(new Error('Template request failed with status 400: invalid model'))
+      .mockResolvedValueOnce({ success: true, imageUrl: 'compat-template-image' })
+
+    await generateImage('user-1', 'openai-compatible:oa-1::gemini-3.1-flash-image', 'draw hero')
+
+    expect(generateImageViaOpenAICompatTemplateMock).toHaveBeenNthCalledWith(1, expect.objectContaining({
+      modelId: 'gemini-3.1-flash-image',
+    }))
+    expect(generateImageViaOpenAICompatTemplateMock).toHaveBeenNthCalledWith(2, expect.objectContaining({
       modelId: 'gemini-3.1-flash-image-preview',
     }))
   })