fix: show merged PR for current branch head (#5877)

src/main/github/client.test.ts

@@ -635,7 +635,7 @@ describe('getPRForBranch', () => {
     })
   })
 
-  it('ignores merged PRs discovered only by branch lookup', async () => {
+  it('ignores merged PRs discovered only by branch lookup when the branch moved on', async () => {
     getOwnerRepoMock.mockResolvedValueOnce({ owner: 'acme', repo: 'widgets' })
     ghExecFileAsyncMock
       .mockResolvedValueOnce({
@@ -670,12 +670,69 @@ describe('getPRForBranch', () => {
           headRefOid: 'head-oid'
         })
       })
+    gitExecFileAsyncMock.mockResolvedValueOnce({
+      stdout: 'new-local-head-oid\n',
+      stderr: ''
+    })
 
     const pr = await getPRForBranch('/repo-root', 'add-guide-for-mobile-emulator-use')
 
     expect(pr).toBeNull()
   })
 
+  it('shows a merged branch PR when it still matches the current HEAD', async () => {
+    getOwnerRepoMock.mockResolvedValueOnce({ owner: 'acme', repo: 'widgets' })
+    ghExecFileAsyncMock
+      .mockResolvedValueOnce({
+        stdout: JSON.stringify([
+          {
+            number: 5875,
+            title: 'Merged current branch PR',
+            state: 'closed',
+            merged_at: '2026-06-20T04:53:05Z',
+            html_url: 'https://github.com/acme/widgets/pull/5875',
+            updated_at: '2026-06-20T04:53:05Z',
+            draft: false,
+            mergeable_state: 'clean',
+            head: { ref: 'fix-tab-strip-layout-test', sha: 'current-head-oid' },
+            base: { ref: 'main', sha: 'base-oid' }
+          }
+        ])
+      })
+      .mockResolvedValueOnce({
+        stdout: JSON.stringify({
+          number: 5875,
+          title: 'Merged current branch PR',
+          state: 'MERGED',
+          url: 'https://github.com/acme/widgets/pull/5875',
+          statusCheckRollup: [],
+          updatedAt: '2026-06-20T04:53:05Z',
+          isDraft: false,
+          mergeable: 'MERGEABLE',
+          baseRefName: 'main',
+          headRefName: 'fix-tab-strip-layout-test',
+          baseRefOid: 'base-oid',
+          headRefOid: 'current-head-oid'
+        })
+      })
+    gitExecFileAsyncMock.mockResolvedValueOnce({
+      stdout: 'current-head-oid\n',
+      stderr: ''
+    })
+
+    const pr = await getPRForBranch('/repo-root', 'fix-tab-strip-layout-test')
+
+    expect(gitExecFileAsyncMock).toHaveBeenCalledWith(['rev-parse', 'HEAD'], {
+      cwd: '/repo-root'
+    })
+    expect(pr).toMatchObject({
+      number: 5875,
+      title: 'Merged current branch PR',
+      state: 'merged',
+      headSha: 'current-head-oid'
+    })
+  })
+
   it('prefers branch lookup over a fallback PR number', async () => {
     getOwnerRepoMock.mockResolvedValueOnce({ owner: 'acme', repo: 'widgets' })
     ghExecFileAsyncMock

src/main/github/client.ts

@@ -2036,6 +2036,38 @@ function isMergedImplicitPR(data: PullRequestLookupData, linkedPRNumber?: number
   return typeof linkedPRNumber !== 'number' && mapPRState(data.state, data.isDraft) === 'merged'
 }
 
+async function getCurrentHeadOid(
+  repoPath: string,
+  connectionId?: string | null,
+  localGitOptions: { wslDistro?: string } = {}
+): Promise<string | null> {
+  try {
+    const provider = connectionId ? getSshGitProvider(connectionId) : null
+    const result = provider
+      ? await provider.exec(['rev-parse', 'HEAD'], repoPath)
+      : await gitExecFileAsync(['rev-parse', 'HEAD'], {
+          cwd: repoPath,
+          ...(localGitOptions.wslDistro ? { wslDistro: localGitOptions.wslDistro } : {})
+        })
+    return result.stdout.trim() || null
+  } catch {
+    return null
+  }
+}
+
+function shouldHideMergedImplicitPR(
+  data: PullRequestLookupData | null,
+  linkedPRNumber: number | null | undefined,
+  currentHeadOid: string | null
+): boolean {
+  if (!data || !isMergedImplicitPR(data, linkedPRNumber)) {
+    return false
+  }
+  // Why: keep hiding historical merged branch matches, but preserve the merged
+  // PR for the exact commit currently checked out in the sidebar.
+  return !currentHeadOid || data.headRefOid !== currentHeadOid
+}
+
 function normalizePullRequestLookupData(data: PullRequestLookupData): PullRequestLookupData {
   return {
     ...data,
@@ -2502,6 +2534,19 @@ export async function getPRForBranchOutcome(
     let data: PullRequestLookupData | null = null
     let dataRepo: OwnerRepo | null = null
     let dataHeadRepo: OwnerRepo | null = headRepo
+    let currentHeadOidForMergedImplicit: string | null | undefined
+
+    const hideMergedImplicitPR = async (candidate: PullRequestLookupData | null) => {
+      if (!candidate || !isMergedImplicitPR(candidate, linkedPRNumber)) {
+        return false
+      }
+      currentHeadOidForMergedImplicit ??= await getCurrentHeadOid(
+        repoPath,
+        connectionId,
+        localGitOptions
+      )
+      return shouldHideMergedImplicitPR(candidate, linkedPRNumber, currentHeadOidForMergedImplicit)
+    }
 
     if (typeof linkedPRNumber === 'number') {
       const exactLookup = await lookupPRByNumber({
@@ -2554,8 +2599,8 @@ export async function getPRForBranchOutcome(
       }
     }
     let mergedBranchLookupNumber: number | null = null
-    if (data && isMergedImplicitPR(data, linkedPRNumber)) {
-      mergedBranchLookupNumber = data.number
+    if (await hideMergedImplicitPR(data)) {
+      mergedBranchLookupNumber = data?.number ?? null
       data = null
       dataRepo = null
       dataHeadRepo = headRepo
@@ -2580,7 +2625,7 @@ export async function getPRForBranchOutcome(
     // marks the fallback as visible review state, keep its lifecycle fresh even
     // if GitHub no longer reports it by branch (for example deleted heads).
     if (
-      isMergedImplicitPR(data, linkedPRNumber) &&
+      (await hideMergedImplicitPR(data)) &&
       !fallbackConfirmedMergedBranch &&
       options.acceptMergedFallbackPR !== true
     ) {