fix(runtime): close lifecycle teardown races

packages/pty/pty-local/src/index.ts

@@ -101,15 +101,30 @@ export class LocalPtyBackend implements PtyBackend {
     ensureSandboxModeFence(this.ctx, spec.owner)
     const argv = spawnArgv(this.ctx, this.config, spec)
     if (argv[0] === undefined) throw new Error('pty-local: sandbox returned empty argv')
-    const terminal = await this.spawnTerminal({
-      argv,
-      cwd: spec.cwd ?? this.ctx.sandboxPolicy.workspaceRoot,
-      env: childEnvironment(spec),
-      rows: this.config.rows,
-      cols: this.config.cols,
-      graceMs: this.config.disposeGraceMs,
-      signal: spec.signal,
-    })
+    let terminalSignal: AbortSignal | undefined
+    let detachSetupSignal: (() => void) | undefined
+    if (spec.signal !== undefined) {
+      const source = spec.signal
+      const controller = new AbortController()
+      const onAbort = (): void => { controller.abort(source.reason) }
+      source.addEventListener('abort', onAbort, { once: true })
+      detachSetupSignal = () => { source.removeEventListener('abort', onAbort) }
+      terminalSignal = controller.signal
+    }
+    let terminal: SubprocessTerminalHandle
+    try {
+      terminal = await this.spawnTerminal({
+        argv,
+        cwd: spec.cwd ?? this.ctx.sandboxPolicy.workspaceRoot,
+        env: childEnvironment(spec),
+        rows: this.config.rows,
+        cols: this.config.cols,
+        graceMs: this.config.disposeGraceMs,
+        signal: terminalSignal,
+      })
+    } finally {
+      detachSetupSignal?.()
+    }
     const session = this.createSession(terminal, this.config)
     try {
       await session.initialize(spec.signal)

packages/pty/pty-local/src/session.ts

@@ -473,17 +473,23 @@ export class LocalPtySession implements PtyBackendSession {
     this.active = undefined
   }
 
-  private failActive(error: unknown): void {
+  private failActive(error: unknown, retainOwnership = false): void {
     const operation = this.active
     if (operation === undefined) return
-    this.clearActive()
+    if (retainOwnership) {
+      this.stopPolling()
+      this.activeAbort?.()
+      this.activeAbort = undefined
+    } else {
+      this.clearActive()
+    }
     operation.fail(error)
   }
 
   private interrupt(operation: LocalSendOperation): void {
     if (this.active !== operation) return
     void this.terminal.signalForeground('SIGINT').catch((error: unknown) => {
-      if (this.active === operation) this.failActive(error)
+      if (this.active === operation) this.failActive(error, this.writing === operation)
     })
   }