fix(terminal): fall back to usable shell for nologin and false (#12242)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

app/Services/TerminalSessionService.php

@@ -109,7 +109,8 @@ class TerminalSessionService
     {
         return 'PATH=$PATH:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin && '.
             'if [ -f ~/.profile ]; then . ~/.profile; fi && '.
-            'if [ -n "$SHELL" ] && [ -x "$SHELL" ]; then exec $SHELL; else sh; fi';
+            'if [ -n "$SHELL" ] && [ -x "$SHELL" ] && [ "${SHELL##*/}" != nologin ] && [ "${SHELL##*/}" != false ]; then exec $SHELL; '.
+            'elif command -v bash >/dev/null 2>&1; then exec bash; else sh; fi';
     }
 
     private function cacheKey(string $token): string

tests/Unit/TerminalShellCommandTest.php

@@ -0,0 +1,36 @@
+<?php
+
+use App\Services\TerminalSessionService;
+use Symfony\Component\Process\Process;
+
+function runTerminalShellCommand(string $shellName, int $exitCode = 1): Process
+{
+    $home = sys_get_temp_dir().'/terminal-shell-'.uniqid();
+    mkdir($home);
+    $shell = "{$home}/{$shellName}";
+    file_put_contents($shell, "#!/bin/sh\necho {$shellName}-ran\nexit {$exitCode}\n");
+    chmod($shell, 0755);
+
+    $command = (fn () => $this->shellCommand())->call(new TerminalSessionService);
+
+    $process = new Process(['sh', '-c', $command], null, ['HOME' => $home, 'SHELL' => $shell]);
+    $process->setInput("echo fallback-ran\n");
+    $process->run();
+
+    return $process;
+}
+
+it('falls back to a usable shell when $SHELL is a login-disabling shell', function (string $shellName) {
+    $process = runTerminalShellCommand($shellName);
+
+    expect($process->getOutput())->toContain('fallback-ran')
+        ->not->toContain("{$shellName}-ran");
+    expect($process->getExitCode())->toBe(0);
+})->with(['nologin', 'false']);
+
+it('starts $SHELL when it is a usable shell', function () {
+    $process = runTerminalShellCommand('zsh', exitCode: 0);
+
+    expect($process->getOutput())->toContain('zsh-ran');
+    expect($process->getExitCode())->toBe(0);
+});