Preserve checks cache on refresh failures

Co-authored-by: Orca <help@stably.ai>

src/main/github/client-pr-checks.test.ts

@@ -103,4 +103,13 @@ describe('getPRChecks', () => {
       }
     ])
   })
+
+  it('throws when both check-runs and gh pr checks fail', async () => {
+    getOwnerRepoMock.mockResolvedValueOnce({ owner: 'acme', repo: 'widgets' })
+    ghExecFileAsyncMock
+      .mockRejectedValueOnce(new Error('gh: No commit found for SHA: stale-head (HTTP 422)'))
+      .mockRejectedValueOnce(new Error('rate limited'))
+
+    await expect(getPRChecks('/repo-root', 42, 'stale-head')).rejects.toThrow('rate limited')
+  })
 })

src/main/github/client.ts

@@ -1232,7 +1232,7 @@ export async function getPRChecks(
     }
   } catch (err) {
     console.warn('getPRChecks failed:', err)
-    return []
+    throw err
   }
 }
 

src/main/github/work-item-details.ts

@@ -579,9 +579,15 @@ export async function getWorkItemDetails(
     // Promise.all above, so there's no ordering requirement between them.
     const [mentionParticipants, checks] = await Promise.all([
       getMentionParticipants(repoPath, item, comments, participants),
-      shas?.headSha
+      (shas?.headSha
         ? getPRChecks(repoPath, item.number, shas.headSha)
         : getPRChecks(repoPath, item.number)
+      ).catch((err) => {
+        // Why: details can still render body/comments/files when check fetching
+        // is rate-limited or temporarily unavailable.
+        console.warn('Failed to fetch PR checks for work item details:', err)
+        return []
+      })
     ])
 
     return {

src/renderer/src/store/slices/github.test.ts

@@ -227,6 +227,62 @@ describe('createGitHubSlice.fetchPRChecks', () => {
       noCache: true
     })
   })
+
+  it('preserves cached checks when the checks IPC fails', async () => {
+    const store = createTestStore()
+    const repoPath = '/repo'
+    const branch = 'feature/test'
+    const checksCacheKey = `${repoPath}::pr-checks::12`
+    const cachedChecks = [
+      { name: 'build', status: 'completed', conclusion: 'failure', url: null } as const
+    ]
+
+    store.setState({
+      checksCache: {
+        [checksCacheKey]: {
+          data: cachedChecks,
+          fetchedAt: 1,
+          headSha: 'abc123head'
+        }
+      }
+    } as unknown as Partial<AppState>)
+    mockApi.gh.prChecks.mockRejectedValueOnce(new Error('rate limited'))
+
+    await expect(
+      store.getState().fetchPRChecks(repoPath, 12, branch, 'abc123head', { force: true })
+    ).resolves.toEqual(cachedChecks)
+
+    expect(store.getState().checksCache[checksCacheKey]?.data).toEqual(cachedChecks)
+    expect(store.getState().checksCache[checksCacheKey]?.fetchedAt).toBe(1)
+  })
+
+  it('does not return cached checks for a different requested head SHA after IPC failure', async () => {
+    const store = createTestStore()
+    const repoPath = '/repo'
+    const branch = 'feature/test'
+    const checksCacheKey = `${repoPath}::pr-checks::12`
+    const oldHeadChecks = [
+      { name: 'build', status: 'completed', conclusion: 'success', url: null } as const
+    ]
+
+    store.setState({
+      checksCache: {
+        [checksCacheKey]: {
+          data: oldHeadChecks,
+          fetchedAt: 1,
+          headSha: 'old-head'
+        }
+      }
+    } as unknown as Partial<AppState>)
+    mockApi.gh.prChecks.mockRejectedValueOnce(new Error('rate limited'))
+
+    await expect(
+      store.getState().fetchPRChecks(repoPath, 12, branch, 'new-head', { force: true })
+    ).resolves.toEqual([])
+
+    expect(store.getState().checksCache[checksCacheKey]?.data).toEqual(oldHeadChecks)
+    expect(store.getState().checksCache[checksCacheKey]?.headSha).toBe('old-head')
+  })
 })
 
 describe('createGitHubSlice.fetchPRForBranch', () => {

src/renderer/src/store/slices/github.ts

@@ -1430,7 +1430,11 @@ export const createGitHubSlice: StateCreator<AppState, [], [], GitHubSlice> = (s
         return checks
       } catch (err) {
         console.error('Failed to fetch PR checks:', err)
-        return get().checksCache[cacheKey]?.data ?? []
+        const latestCached = get().checksCache[cacheKey]
+        if (latestCached?.data && (!headSha || latestCached.headSha === headSha)) {
+          return latestCached.data
+        }
+        return []
       } finally {
         inflightChecksRequests.delete(inflightKey)
       }