Add detachable SSH PTY daemon persistence

.github/workflows/ci.yml

@@ -398,12 +398,9 @@ jobs:
     runs-on: ${{ vars.MACOS_RUNNER_15 || 'warp-macos-15-arm64-6x' }}
     # A cold DerivedData cache (any project.pbxproj or Package.resolved change
     # mints a new cache key with no restore-keys fallback) forces a full
-    # cmux build whose Swift codegen alone runs ~18-20 min, so 20 was right at
-    # the edge and got guillotined mid-build (the post-cache step never ran, so
-    # the cache stayed cold and every retry timed out the same way). 35 gives a
-    # cold build enough room to finish and populate the cache. Extension project
-    # and package graph changes can still spend more than 35 minutes in the
-    # build step before the lag regression starts.
+    # cmux build whose Swift codegen alone can run 20+ min. Project/package
+    # changes from the sidebar extension kit pushed this full build plus the
+    # CA and lag regressions beyond 35 min before the cache could repopulate.
     timeout-minutes: 55
     steps:
       - name: Checkout

.github/workflows/tmux-corpus.yml

@@ -1,6 +1,10 @@
 name: tmux corpus
 
 on:
+  pull_request:
+    paths:
+      - ".github/workflows/tmux-corpus.yml"
+      - "daemon/remote/**"
   workflow_dispatch:
     inputs:
       fuzztime:
@@ -41,7 +45,7 @@ jobs:
       - name: Run tmux corpus fuzz targets
         working-directory: daemon/remote
         env:
-          FUZZTIME: ${{ github.event.inputs.fuzztime || '2m' }}
+          FUZZTIME: ${{ github.event_name == 'pull_request' && '30s' || github.event.inputs.fuzztime || '2m' }}
         run: |
           set -euo pipefail
           for target in \

CLI/cmux.swift

@@ -7461,6 +7461,9 @@ struct CMUXCLI {
             sshOptions.extraArguments.isEmpty &&
             remoteTerminalBootstrapScript?.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == false &&
             deferredRemoteReconnectCommandScript != nil
+        let persistentDaemonSlot = usesPersistentSSHPTY
+            ? "ssh-\(UUID().uuidString.lowercased())"
+            : nil
         let startupInitialSSHCommand = buildSSHCommandText(
             sshOptions,
             localCommandScript: combinedLocalCommandScript
@@ -7612,8 +7615,9 @@ struct CMUXCLI {
             if sshOptions.skipDaemonBootstrap {
                 configureParams["skip_daemon_bootstrap"] = true
             }
-            if usesPersistentSSHPTY {
+            if let persistentDaemonSlot {
                 configureParams["preserve_after_terminal_exit"] = true
+                configureParams["persistent_daemon_slot"] = persistentDaemonSlot
             }
 
             cliDebugLog(
@@ -7682,6 +7686,9 @@ struct CMUXCLI {
         if usesPersistentSSHPTY, let workspaceInitialSurfaceId {
             payload["ssh_pty_session_id"] = "ssh-\(workspaceId)-\(workspaceInitialSurfaceId)"
         }
+        if let persistentDaemonSlot {
+            payload["persistent_daemon_slot"] = persistentDaemonSlot
+        }
         logSSHTiming("complete", extra: "workspace=\(String(workspaceId.prefix(8)))")
         if jsonOutput {
             print(jsonString(formatIDs(payload, mode: idFormat)))
@@ -9779,14 +9786,15 @@ struct CMUXCLI {
         let quotedSessionID = shellQuote(sessionID)
         let currentExecutable = shellQuote(resolvedExecutableURL()?.path ?? (args.first ?? "cmux"))
         let attachCommand = "\"$cmux_ssh_attach_cli\" --socket \"$CMUX_SOCKET_PATH\" ssh-pty-attach --wait --require-existing --workspace \"$CMUX_WORKSPACE_ID\" --session-id \(quotedSessionID) --attachment-id \"${CMUX_SURFACE_ID:-}\""
-        return ([
+        let script = ([
             "cmux_ssh_attach_cli=\"${CMUX_BUNDLED_CLI_PATH:-}\"",
             "if [ -z \"$cmux_ssh_attach_cli\" ] || [ ! -x \"$cmux_ssh_attach_cli\" ]; then cmux_ssh_attach_cli=\(currentExecutable); fi",
             "if [ -z \"$cmux_ssh_attach_cli\" ] || [ ! -x \"$cmux_ssh_attach_cli\" ]; then cmux_ssh_attach_cli=\"$(command -v cmux 2>/dev/null || true)\"; fi",
             "if [ -z \"$cmux_ssh_attach_cli\" ]; then printf '%s\\n' '[cmux] bundled CLI not found for SSH PTY attach.' >&2; exit 127; fi",
             "if [ -z \"${CMUX_SOCKET_PATH:-}\" ]; then printf '%s\\n' '[cmux] required configuration missing for SSH PTY attach.' >&2; exit 1; fi",
             "if [ -z \"${CMUX_WORKSPACE_ID:-}\" ]; then printf '%s\\n' '[cmux] required workspace context missing for SSH PTY attach.' >&2; exit 1; fi",
         ] + sshPTYAttachRetryLoopLines(command: attachCommand)).joined(separator: "\n")
+        return "/bin/sh -c \(shellQuote(script))"
     }
 
     private func sshPTYAttachRetryLoopLines(command: String) -> [String] {