fix(registry): retry skills-raw tree outages

layers/registry/server/api/skills-raw/[...slug].get.ts

@@ -64,14 +64,22 @@ export default defineApiHandler({
     })
     const branch = repoMeta?.defaultBranch || 'main'
 
-    const treeRes = await $fetch<{ files?: { path: string }[] }>(
+    const treeResult = await $fetch<{ files?: { path: string }[] }>(
       `https://ungh.cc/repos/${source.owner}/${source.repo}/files/${branch}`,
-    ).catch(() => {
-      emitOperationalEvent(createWideEvent({ operation: 'skill-raw-tree-fetch', outcome: 'failed' }))
-      return null
-    })
+    ).then(
+      response => ({ _tag: 'available' as const, files: response.files ?? [] }),
+      () => {
+        emitOperationalEvent(createWideEvent({ operation: 'skill-raw-tree-fetch', outcome: 'failed' }))
+        return { _tag: 'unavailable' as const }
+      },
+    )
+
+    if (treeResult._tag === 'unavailable') {
+      setHeader(event, 'retry-after', RAW_RETRY_AFTER)
+      throw createError({ statusCode: 503, message: 'Skill source is unavailable upstream' })
+    }
 
-    const files = treeRes?.files ?? []
+    const files = treeResult.files
     const slugifiedName = skill.name.toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/^-+|-+$/g, '')
     const skillPath = files.find(f =>
       f.path.toLowerCase().endsWith(`/${slugifiedName}/skill.md`)

test/unit/skills-raw-tree-outage.test.ts

@@ -0,0 +1,60 @@
+import type { H3Event } from 'h3'
+import type { SqliteD1 } from './helpers/d1-sqlite'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { allMigrations, createSqliteD1 } from './helpers/d1-sqlite'
+
+let fixture: SqliteD1
+let cache: {
+  getItem: ReturnType<typeof vi.fn>
+  setItem: ReturnType<typeof vi.fn>
+}
+const responseHeaders = new Map<string, string | number>()
+
+beforeEach(() => {
+  vi.resetModules()
+  responseHeaders.clear()
+  fixture = createSqliteD1(allMigrations())
+  fixture.raw.prepare(`INSERT INTO repos (owner, repo) VALUES ('owner', 'repo')`).run()
+  fixture.raw.prepare(
+    `INSERT INTO skills (owner, repo, name, slug, display_name, source_resolved)
+     VALUES ('owner', 'repo', 'skill', 'owner/repo/skill', 'Skill', 1)`,
+  ).run()
+  cache = {
+    getItem: vi.fn().mockResolvedValue(null),
+    setItem: vi.fn().mockResolvedValue(undefined),
+  }
+
+  vi.stubGlobal('defineEventHandler', (handler: unknown) => handler)
+  vi.stubGlobal('getRouterParam', () => 'owner/repo/skill')
+  vi.stubGlobal('getUserSession', () => Promise.resolve({ user: { id: 1, login: 'tester' } }))
+  vi.stubGlobal('useStorage', () => cache)
+  vi.stubGlobal('setHeader', (_event: H3Event, name: string, value: string | number) => {
+    responseHeaders.set(name, value)
+  })
+  vi.stubGlobal('$fetch', vi.fn()
+    .mockResolvedValueOnce({ defaultBranch: 'main' })
+    .mockRejectedValueOnce(new Error('tree unavailable')))
+})
+
+afterEach(() => {
+  fixture.close()
+  vi.unstubAllGlobals()
+})
+
+describe('skills-raw tree outage', () => {
+  it('returns a retryable error without caching the Skill as missing', async () => {
+    const handler = (await import('../../layers/registry/server/api/skills-raw/[...slug].get')).default
+
+    await expect(handler(event())).rejects.toMatchObject({ statusCode: 503 })
+
+    expect(cache.setItem).not.toHaveBeenCalled()
+    expect(responseHeaders.get('retry-after')).toBe(30)
+  })
+})
+
+function event(): H3Event {
+  return {
+    method: 'GET',
+    context: { platform: { db: fixture.db } },
+  } as unknown as H3Event
+}