fix(remote): hand remote/docker launch commands to bash verbatim

respawn-pane runs `bash -c "<ssh …>"` through the local sh, so every `$` in
the remote command is expanded on the Codeman host. withRemoteTmuxPath
(`export PATH="$HOME/.local/bin:…:$PATH"; tmux …`, 5b9445de) therefore sends
the Codeman host's home and PATH to the remote host: a remote user with a
different home (tmux in ~/.nix-profile/bin) gets "tmux: command not found" and
every new remote pane exits 127. `${SHELL:-/bin/sh}` in the remote launch was
the local shell for the same reason.

Remote and docker commands are already quoted for the far end, so they now go
to `bash -c` single-quoted (bashCArg); local commands keep the double-quoted
form. Two tests run the captured respawn-pane line (create and respawn)
through a real sh with a foreign HOME/PATH and check that ssh gets `$HOME` and
`$PATH` unexpanded.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(cherry picked from commit 2818e9455489b9acd65841258df4cd035609954c)

src/tmux-manager.ts

@@ -2661,7 +2661,7 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
       // pane launch in /tmp, then cd inside bash against the current mount table.
       const launchCmd = remote || docker ? fullCmd : `cd ${JSON.stringify(workingDir)} && ${fullCmd}`;
       execSync(
-        `${this.tmux()} respawn-pane -k -c ${TMUX_LAUNCH_CWD} -t "${muxName}" bash -c ${JSON.stringify(launchCmd)}`,
+        `${this.tmux()} respawn-pane -k -c ${TMUX_LAUNCH_CWD} -t "${muxName}" bash -c ${bashCArg(launchCmd, !!(remote || docker))}`,
         {
           timeout: EXEC_TIMEOUT_MS,
           stdio: 'ignore',
@@ -2914,7 +2914,7 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
       // -c /tmp + cd bounce — see createSession() for rationale (stale FUSE state).
       const launchCmd = remote || docker ? fullCmd : `cd ${JSON.stringify(workingDir)} && ${fullCmd}`;
       await execAsync(
-        `${this.tmux()} respawn-pane -k -c ${TMUX_LAUNCH_CWD} -t "${muxName}" bash -c ${JSON.stringify(launchCmd)}`,
+        `${this.tmux()} respawn-pane -k -c ${TMUX_LAUNCH_CWD} -t "${muxName}" bash -c ${bashCArg(launchCmd, !!(remote || docker))}`,
         {
           timeout: EXEC_TIMEOUT_MS,
         }
@@ -4663,6 +4663,20 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
   }
 }
 
+/**
+ * The `bash -c` argument of a pane launch (`respawn-pane … bash -c <arg>`, run through the
+ * local sh). A remote or docker command is already quoted for the shell at the far end and
+ * must reach bash verbatim, so it goes in single quotes. Double quotes (JSON.stringify) let
+ * the local sh expand every `$` first: the PATH bootstrap of `withRemoteTmuxPath`
+ * (`$HOME/.local/bin:…:$PATH`) arrived on the remote host as this host's home and PATH, so
+ * a remote user with another home found no tmux and every new remote pane exited 127.
+ * `${SHELL:-/bin/sh}` in the remote launch was the local shell for the same reason.
+ * Local commands keep their double-quoted form.
+ */
+function bashCArg(launchCmd: string, verbatim: boolean): string {
+  return verbatim ? shellescape(launchCmd) : JSON.stringify(launchCmd);
+}
+
 /**
  * Shell-escape a string for use as a single argument.
  * Wraps in single quotes, escaping any embedded single quotes.

test/tmux-manager.test.ts

@@ -28,6 +28,20 @@ import type { MuxSession } from '../src/mux-interface.js';
 // ============================================================================
 
 // Mock child_process
+/**
+ * Runs a captured `… respawn-pane … bash -c <arg>` line through a real local sh (with a
+ * foreign HOME/PATH) and returns the string bash would get, i.e. what ssh sends on.
+ */
+async function bashArgAfterLocalShell(respawnCmd: string): Promise<string> {
+  const real = await vi.importActual<typeof import('node:child_process')>('node:child_process');
+  const at = respawnCmd.indexOf(' bash -c ');
+  expect(at).toBeGreaterThan(0);
+  return real.execFileSync('/bin/sh', ['-c', `printf '%s' ${respawnCmd.slice(at + ' bash -c '.length)}`], {
+    env: { HOME: '/local-home-xyz', PATH: '/local-path-xyz:/usr/bin:/bin' },
+    encoding: 'utf8',
+  });
+}
+
 vi.mock('node:child_process', async () => {
   const actual = await vi.importActual('node:child_process');
   return {
@@ -865,6 +879,66 @@ describe('TmuxManager (unit)', () => {
       }
     });
 
+    it('hands a remote launch to ssh with $HOME and $PATH unexpanded', async () => {
+      // respawn-pane runs `bash -c <arg>` through the local sh. In double quotes that sh
+      // expanded withRemoteTmuxPath's `$HOME/…:$PATH` to the Codeman host's values, so a
+      // remote user with another home found no tmux and the pane exited 127.
+      const NonTestTmuxManager = await importWithTmuxCommandsEnabled();
+      const nonTestManager = new NonTestTmuxManager();
+
+      try {
+        await nonTestManager.createSession({
+          sessionId: 'abc12345-1234-5678-90ab-cdef12345679',
+          workingDir: '/w',
+          mode: 'shell',
+          remote: { hostId: 'gpu-box', label: 'GPU Box', host: '10.0.0.42', username: 'ubuntu', remotePath: '/w' },
+        });
+        const launch = [...mockedExecSync.mock.calls, ...vi.mocked(exec).mock.calls]
+          .map(([cmd]) => cmd)
+          .find((cmd) => typeof cmd === 'string' && cmd.includes(' respawn-pane '));
+        const sent = await bashArgAfterLocalShell(launch as string);
+        expect(sent).toContain('ssh ');
+        expect(sent).toContain('export PATH="$HOME/');
+        expect(sent).toContain(':$PATH"; tmux ');
+        expect(sent).not.toContain('local-home-xyz');
+        expect(sent).not.toContain('local-path-xyz');
+      } finally {
+        nonTestManager.destroy();
+      }
+    });
+
+    it('respawns a remote pane with $HOME unexpanded as well', async () => {
+      const NonTestTmuxManager = await importWithTmuxCommandsEnabled();
+      const nonTestManager = new NonTestTmuxManager();
+      nonTestManager.registerSession({
+        sessionId: 'respawnremote2',
+        muxName: 'codeman-abcd8888',
+        pid: 1000,
+        createdAt: Date.now(),
+        workingDir: '/w',
+        mode: 'shell',
+        attached: false,
+      });
+
+      try {
+        await nonTestManager.respawnPane({
+          sessionId: 'respawnremote2',
+          workingDir: '/w',
+          mode: 'shell',
+          remote: { hostId: 'gpu-box', label: 'GPU Box', host: '10.0.0.42', username: 'ubuntu', remotePath: '/w' },
+        });
+        const { exec: currentExec } = await import('node:child_process');
+        const respawnCall = vi
+          .mocked(currentExec)
+          .mock.calls.find(([cmd]) => typeof cmd === 'string' && cmd.includes(' respawn-pane '));
+        const sent = await bashArgAfterLocalShell(respawnCall?.[0] as string);
+        expect(sent).toContain('export PATH="$HOME/');
+        expect(sent).not.toContain('local-home-xyz');
+      } finally {
+        nonTestManager.destroy();
+      }
+    });
+
     it('changes the global history default on tmux versions that cannot resize panes', async () => {
       const NonTestTmuxManager = await importWithTmuxCommandsEnabled();
       const nonTestManager = new NonTestTmuxManager();