fix: harden reused PTY lifecycle ordering

config/reliability-gates.jsonc

@@ -3264,7 +3264,7 @@
           "file": "src/renderer/src/components/terminal-pane/pty-pre-handler-buffer.test.ts",
           "assertions": [
             "65 exit-before-handler identities evict the oldest and retain the newest",
-            "a reused PTY id refreshes recency, delivers only its latest exit once, and filters older-lifecycle data and exits by cursor",
+            "a reused PTY id refreshes both data and exit recency, delivers only its latest exit once, and filters older-lifecycle data and exits by cursor",
             "warning identities are released with exact data-map eviction so warning state cannot grow independently"
           ]
         },
@@ -3272,7 +3272,7 @@
           "file": "src/renderer/src/components/terminal-pane/pty-dispatcher-pi-routing.test.ts",
           "assertions": [
             "pre-handler data drains before its exit",
-            "fresh PTY-id reuse filters old lifecycle events while explicit daemon reattach preserves pre-connect backlog",
+            "fresh PTY-id reuse and failed-reattach fresh fallback filter old lifecycle events while explicit daemon reattach preserves pre-connect backlog",
             "a registered exit handler remains authoritative while 65 orphan exits churn through the bounded buffer"
           ]
         },
@@ -3291,7 +3291,7 @@
           "command": "pnpm exec vitest run --config config/vitest.config.ts src/renderer/src/components/terminal-pane/pty-pre-handler-buffer.test.ts src/renderer/src/components/terminal-pane/pty-transport.test.ts src/renderer/src/components/terminal-pane/pty-dispatcher-pi-routing.test.ts src/renderer/src/lib/launch-agent-background-session.test.ts src/renderer/src/lib/launch-worktree-background-terminals.test.ts",
           "result": "passed",
           "durationSeconds": 1,
-          "summary": "5 test files passed, 112 tests passed on main@20ebe858af plus the #7695 candidate. The current-main repro retained the 65th oldest exit (received code 0 instead of eviction); the bounded candidate evicts it and preserves all ordering/reuse cases."
+          "summary": "5 test files passed, 114 tests passed on main@20ebe858af plus the #7695 candidate. Main@20ebe858af retained the 65th oldest exit (received code 0 instead of eviction); the bounded candidate evicts it and preserves all ordering/reuse cases."
         }
       ],
       "runtimeBudget": {

src/renderer/src/components/terminal-pane/pty-dispatcher-pi-routing.test.ts

@@ -368,6 +368,38 @@ describe('dispatcher → transport → onTitleChange for Pi spinner', () => {
     expect(events).toEqual(['data:new-data', 'exit:2'])
   })
 
+  it('filters an older lifecycle when a failed reattach spawns fresh with the same id', async () => {
+    const { createIpcPtyTransport } = await import('./pty-transport')
+    const { ensurePtyDispatcher } = await import('./pty-dispatcher')
+    const events: string[] = []
+    let resolveSpawn: (value: { id: string }) => void = () => {}
+
+    ensurePtyDispatcher()
+    dispatcherCallback?.({ id: 'pty-reattach-fallback', data: 'old-data' })
+    exitDispatcherCallback?.({ id: 'pty-reattach-fallback', code: 1 })
+    ;(window.api.pty.spawn as ReturnType<typeof vi.fn>).mockReturnValueOnce(
+      new Promise((resolve) => {
+        resolveSpawn = resolve
+      })
+    )
+
+    const transport = createIpcPtyTransport()
+    const connectPromise = transport.connect({
+      url: '',
+      sessionId: 'pty-reattach-fallback',
+      callbacks: {
+        onData: (data) => events.push(`data:${data}`),
+        onExit: (code) => events.push(`exit:${code}`)
+      }
+    })
+    dispatcherCallback?.({ id: 'pty-reattach-fallback', data: 'fresh-data' })
+    exitDispatcherCallback?.({ id: 'pty-reattach-fallback', code: 2 })
+    resolveSpawn({ id: 'pty-reattach-fallback' })
+    await connectPromise
+
+    expect(events).toEqual(['data:fresh-data', 'exit:2'])
+  })
+
   it('preserves pre-connect backlog for an explicit daemon reattach', async () => {
     const { createIpcPtyTransport } = await import('./pty-transport')
     const { ensurePtyDispatcher } = await import('./pty-dispatcher')

src/renderer/src/components/terminal-pane/pty-pre-handler-buffer.test.ts

@@ -20,6 +20,10 @@ const WARN_PTY_IDS = Array.from(
   { length: PRE_HANDLER_PTY_MAX_PTYS + 1 },
   (_, index) => `pty-pre-handler-warn-${index}`
 )
+const DATA_PTY_IDS = Array.from(
+  { length: PRE_HANDLER_PTY_MAX_PTYS + 1 },
+  (_, index) => `pty-pre-handler-data-${index}`
+)
 
 describe('pre-handler PTY buffer', () => {
   afterEach(() => {
@@ -32,6 +36,9 @@ describe('pre-handler PTY buffer', () => {
     for (const ptyId of WARN_PTY_IDS) {
       clearPreHandlerPtyState(ptyId)
     }
+    for (const ptyId of DATA_PTY_IDS) {
+      clearPreHandlerPtyState(ptyId)
+    }
   })
 
   it('does not rescan historical chunks while buffering small startup output', () => {
@@ -128,6 +135,26 @@ describe('pre-handler PTY buffer', () => {
     expect(reusedHandler).toHaveBeenCalledWith(99)
   })
 
+  it('refreshes data recency when a reused PTY id receives current lifecycle output', () => {
+    bufferPreHandlerPtyData(DATA_PTY_IDS[0], 'old-data')
+    for (let index = 1; index < PRE_HANDLER_PTY_MAX_PTYS; index += 1) {
+      bufferPreHandlerPtyData(DATA_PTY_IDS[index], `data-${index}`)
+    }
+
+    bufferPreHandlerPtyData(DATA_PTY_IDS[0], 'current-data')
+    bufferPreHandlerPtyData(DATA_PTY_IDS.at(-1)!, 'newest-data')
+
+    const oldestHandler = vi.fn()
+    drainPreHandlerPtyData(DATA_PTY_IDS[1], oldestHandler)
+    expect(oldestHandler).not.toHaveBeenCalled()
+    const reusedHandler = vi.fn()
+    drainPreHandlerPtyData(DATA_PTY_IDS[0], reusedHandler)
+    expect(reusedHandler.mock.calls).toEqual([
+      ['old-data', undefined],
+      ['current-data', undefined]
+    ])
+  })
+
   it('clears an old lifecycle before a PTY id is reused and drains the new exit once', () => {
     const ptyId = EXIT_PTY_IDS[0]
     bufferPreHandlerPtyExit(ptyId, 1)

src/renderer/src/components/terminal-pane/pty-pre-handler-buffer.ts

@@ -58,6 +58,11 @@ export function bufferPreHandlerPtyData(ptyId: string, data: string, meta?: PtyD
   if (!state) {
     state = { chunks: [], head: 0, bytes: 0 }
     preHandlerPtyData.set(ptyId, state)
+  } else {
+    // Why: relay-style providers can reuse ids. New output makes this identity
+    // current, so later churn must evict an actually older buffered PTY.
+    preHandlerPtyData.delete(ptyId)
+    preHandlerPtyData.set(ptyId, state)
   }
   state.chunks.push({
     data: chunk.data,

src/renderer/src/components/terminal-pane/pty-transport.ts

@@ -691,7 +691,9 @@ export function createIpcPtyTransport(opts: IpcPtyTransportOptions = {}): PtyTra
       }
 
       try {
-        const freshSpawnCursor = options.sessionId ? undefined : capturePreHandlerPtyEventCursor()
+        // Why: a requested reattach can fall back to a fresh PTY with the same
+        // id. Keep the cursor unless the provider confirms an actual restore.
+        const freshSpawnCursor = capturePreHandlerPtyEventCursor()
         // Why: missing-cwd recovery is only valid for fresh local spawns —
         // reattach must keep the session's exact cwd and SSH-tagged transports
         // resolve cwd on the remote host.