fix(terminal): scope pre-handler state to admission

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

@@ -137,6 +137,52 @@ describe('pre-handler PTY buffer', () => {
     expect(handler).toHaveBeenCalledWith(-1)
   })
 
+  it('keeps a replacement probe owned when an older same-id probe settles', async () => {
+    const target = 'pty-reused-probe-owner'
+    const oldPrefix = 'pty-reused-probe-old-'
+    const newPrefix = 'pty-reused-probe-new-'
+    const resolvers: ((alive: boolean | null) => void)[] = []
+    const hasPty = vi.fn(
+      () =>
+        new Promise<boolean | null>((resolve) => {
+          resolvers.push(resolve)
+        })
+    )
+    const handler = vi.fn()
+    try {
+      bufferPreHandlerPtyExit(target, 1)
+      for (let index = 0; index < 64; index += 1) {
+        bufferPreHandlerPtyExit(`${oldPrefix}${index}`, index)
+      }
+      reconcilePreHandlerPtyExitAfterOverflow(target, hasPty, handler, () => true)
+
+      clearPreHandlerPtyState(target)
+      bufferPreHandlerPtyExit(target, 2)
+      for (let index = 0; index < 64; index += 1) {
+        bufferPreHandlerPtyExit(`${newPrefix}${index}`, index)
+      }
+      reconcilePreHandlerPtyExitAfterOverflow(target, hasPty, handler, () => true)
+      expect(hasPty).toHaveBeenCalledTimes(2)
+
+      resolvers[0]?.(true)
+      await Promise.resolve()
+      await Promise.resolve()
+      await Promise.resolve()
+      reconcilePreHandlerPtyExitAfterOverflow(target, hasPty, handler, () => true)
+
+      expect(hasPty).toHaveBeenCalledTimes(2)
+      expect(handler).not.toHaveBeenCalled()
+      resolvers[1]?.(true)
+      await Promise.resolve()
+    } finally {
+      clearPreHandlerPtyState(target)
+      for (let index = 0; index < 64; index += 1) {
+        clearPreHandlerPtyState(`${oldPrefix}${index}`)
+        clearPreHandlerPtyState(`${newPrefix}${index}`)
+      }
+    }
+  })
+
   it('caps eviction tombstones at exactly 1024 ids without probing unrelated PTYs', async () => {
     const prefix = 'pty-exact-tombstone-cap-'
     const hasPty = vi.fn(async () => false)

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

@@ -26,7 +26,7 @@ const PRE_HANDLER_PTY_EXIT_MAX_PTYS = 64
 // window avoids turning one overflow into liveness IPC for unrelated panes.
 const PRE_HANDLER_PTY_EVICTED_EXIT_MAX_PTYS = 1_024
 const preHandlerPtyEvictedExitIds = new Set<string>()
-const preHandlerPtyEvictedExitProbes = new Set<string>()
+const preHandlerPtyEvictedExitProbes = new Map<string, symbol>()
 // Why: legit pre-attach windows drain within milliseconds and hold little
 // data. Sustained accumulation means a pane lost its data handler (the
 // frozen-pane detach/attach race) — leave a breadcrumb for trace capture.
@@ -137,12 +137,18 @@ export function reconcilePreHandlerPtyExitAfterOverflow(
   ) {
     return
   }
-  preHandlerPtyEvictedExitProbes.add(ptyId)
+  const probeToken = Symbol(ptyId)
+  preHandlerPtyEvictedExitProbes.set(ptyId, probeToken)
   // Why: the bounded exit buffer may evict a legitimate pre-registration exit.
   // Keep its tombstone through unknown liveness so reconnect can retry proof.
   void hasPty(ptyId)
     .then((alive) => {
-      if (!isCurrent() || !preHandlerPtyEvictedExitIds.has(ptyId) || alive === null) {
+      if (
+        preHandlerPtyEvictedExitProbes.get(ptyId) !== probeToken ||
+        !isCurrent() ||
+        !preHandlerPtyEvictedExitIds.has(ptyId) ||
+        alive === null
+      ) {
         return
       }
       preHandlerPtyEvictedExitIds.delete(ptyId)
@@ -152,7 +158,10 @@ export function reconcilePreHandlerPtyExitAfterOverflow(
     })
     .catch(() => {})
     .finally(() => {
-      preHandlerPtyEvictedExitProbes.delete(ptyId)
+      // Why: a stale probe must not clear a newer same-ID generation's owner.
+      if (preHandlerPtyEvictedExitProbes.get(ptyId) === probeToken) {
+        preHandlerPtyEvictedExitProbes.delete(ptyId)
+      }
     })
 }
 

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

@@ -147,6 +147,27 @@ describe('createIpcPtyTransport', () => {
     expect(onDataCallback).not.toHaveBeenCalledWith('dead generation output')
   })
 
+  it('does not drain an exit buffered before a same-id admission starts', async () => {
+    const { createIpcPtyTransport, ensurePtyDispatcher } = await import('./pty-transport')
+    const spawn = window.api.pty.spawn as unknown as ReturnType<typeof vi.fn>
+    spawn.mockResolvedValueOnce({ id: 'same-id' })
+    ensurePtyDispatcher()
+    onExit?.({ id: 'same-id', code: 17 })
+    const observedExit = vi.fn()
+    const transport = createIpcPtyTransport()
+
+    await transport.connect({
+      url: '',
+      sessionId: 'same-id',
+      callbacks: { onExit: observedExit }
+    })
+
+    expect(transport.isConnected()).toBe(true)
+    expect(transport.getPtyId()).toBe('same-id')
+    expect(observedExit).not.toHaveBeenCalled()
+    transport.disconnect()
+  })
+
   it('preserves replacement startup events while an older same-id admission rejects', async () => {
     const { createIpcPtyTransport } = await import('./pty-transport')
     const spawn = window.api.pty.spawn as unknown as ReturnType<typeof vi.fn>

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

@@ -708,6 +708,11 @@ export function createIpcPtyTransport(opts: IpcPtyTransportOptions = {}): PtyTra
         ? await acquirePtySessionConnectAdmission(options.sessionId)
         : undefined
       try {
+        if (options.sessionId) {
+          // Why: admission starts a new renderer generation; buffered events
+          // that predate this boundary belong to the previous same-ID owner.
+          clearPreHandlerPtyState(options.sessionId)
+        }
         storedCallbacks = options.callbacks
         if (destroyed) {
           return