fix: harden ssh script shell compatibility

scripts/src/ssh.ts

@@ -88,6 +88,7 @@ const windowsCmdExeNativePath = "C:\\Windows\\System32\\cmd.exe";
 const defaultSshSlowWarningMs = 10_000;
 const defaultSshRuntimeTimeoutMs = 60_000;
 const maxSshRuntimeTimeoutMs = 60_000;
+export const sshShellCompatibilityPrelude = 'printf(){ if [ "${1+x}" = x ] && [ "$1" = "-v" ] && [ -n "${BASH_VERSION:-}" ]; then command printf "$@"; return $?; fi; if [ "${1+x}" = x ] && [ "$1" = "--" ]; then shift; fi; command printf -- "$@"; }';
 const k3sResourceKindAliases = new Set(["pod", "po", "pods", "deployment", "deploy", "deployments", "statefulset", "sts", "daemonset", "ds", "job", "jobs"]);
 const legacyK3sOperationRouteSegments = new Set([
   "guard",
@@ -1326,7 +1327,7 @@ function parseK3sControlPlaneOperation(route: ParsedSshRoute, args: string[]): P
   }
   if (operation === "shell") {
     const parsed = parseShellStringOperationArgs(args.slice(1), `ssh ${route.providerId}:k3s shell`);
-    return { remoteCommand: shellArgv(["env", `KUBECONFIG=${nativeK3sKubeconfig}`, parsed.shell, "-c", parsed.command]), requiresStdin: false, invocationKind: "helper" };
+    return { remoteCommand: shellArgv(["env", `KUBECONFIG=${nativeK3sKubeconfig}`, parsed.shell, "-c", shellScriptWithCompatibility(parsed.command)]), requiresStdin: false, invocationKind: "helper" };
   }
   if (operation === "guard") {
     if (args.length > 1) throw new Error(`ssh ${route.providerId}:k3s guard does not accept extra arguments`);
@@ -1362,7 +1363,7 @@ function parseK3sTargetOperation(route: ParsedSshRoute, args: string[]): ParsedS
   if (operation === "script") return buildK3sScriptOperation([...targetArgs, ...operationArgs]);
   if (operation === "shell") {
     const parsed = parseShellStringOperationArgs(operationArgs, `ssh ${route.raw} shell`);
-    return { remoteCommand: buildK3sExecCommand([...targetArgs, "--", parsed.shell, "-c", parsed.command]), requiresStdin: false, invocationKind: "helper" };
+    return { remoteCommand: buildK3sExecCommand([...targetArgs, "--", parsed.shell, "-c", shellScriptWithCompatibility(parsed.command)]), requiresStdin: false, invocationKind: "helper" };
   }
   if (operation === "logs") return { remoteCommand: buildK3sLogsCommand([...targetArgs, ...operationArgs]), requiresStdin: false, invocationKind: "helper" };
   if (operation === "argv") return { remoteCommand: buildK3sExecCommand([...targetArgs, ...k3sRouteCommandArgs(operationArgs)]), requiresStdin: false, invocationKind: "argv" };
@@ -1520,7 +1521,7 @@ function buildK3sScriptOperation(args: string[]): ParsedSshArgs {
   if (parsed.shell === null && parsed.command.length > 0) {
     return { remoteCommand: buildK3sInlineScriptCommand(parsed), requiresStdin: false, invocationKind: "helper" };
   }
-  return { remoteCommand: buildK3sStdinScriptCommand(parsed), requiresStdin: true, invocationKind: "helper" };
+  return { remoteCommand: buildK3sStdinScriptCommand(parsed), requiresStdin: true, invocationKind: "helper", stdinPrefix: shellScriptStdinPrefix() };
 }
 
 function buildK3sStdinScriptCommand(parsed: K3sTargetOptions): string {
@@ -1546,7 +1547,7 @@ function buildK3sInlineScriptCommand(parsed: K3sTargetOptions): string {
   if (parsed.command.length === 0) throw new Error("ssh k3s script -- requires a command");
   if (parsed.tty) throw new Error("ssh k3s script does not support --tty; stdin is reserved for the script body");
   if (parsed.stdin) throw new Error("ssh k3s script -- does not accept --stdin");
-  const command = parsed.command.length === 1 ? ["sh", "-c", parsed.command[0] ?? ""] : parsed.command;
+  const command = parsed.command.length === 1 ? ["sh", "-c", shellScriptWithCompatibility(parsed.command[0] ?? "")] : parsed.command;
   if (parsed.namespace === null && parsed.resource === null) {
     if (parsed.container !== null) throw new Error("ssh k3s script without a workload does not accept --container");
     if (parsed.workspace !== null) throw new Error("ssh k3s script without a workload does not accept --workdir");
@@ -1770,6 +1771,14 @@ function k3sScriptShell(value: string, option: string): string {
   return value;
 }
 
+function shellScriptWithCompatibility(command: string): string {
+  return `${sshShellCompatibilityPrelude}\n${command}`;
+}
+
+function shellScriptStdinPrefix(): string {
+  return `${sshShellCompatibilityPrelude}\n`;
+}
+
 function buildShellCommand(args: string[]): ParsedSshArgs {
   let shell = "sh";
   const scriptArgs: string[] = [];
@@ -1802,15 +1811,15 @@ function buildShellCommand(args: string[]): ParsedSshArgs {
   }
   if (directArgvMode) {
     if (scriptArgs.length === 0) throw new Error("ssh script -- requires a command");
-    if (scriptArgs.length === 1) return { remoteCommand: shellArgv([shell, "-c", scriptArgs[0] ?? ""]), requiresStdin: false, invocationKind: "helper" };
+    if (scriptArgs.length === 1) return { remoteCommand: shellArgv([shell, "-c", shellScriptWithCompatibility(scriptArgs[0] ?? "")]), requiresStdin: false, invocationKind: "helper" };
     return { remoteCommand: shellArgv(scriptArgs), requiresStdin: false, invocationKind: "argv" };
   }
-  return { remoteCommand: shellArgv([shell, "-s", "--", ...scriptArgs]), requiresStdin: true, invocationKind: "helper" };
+  return { remoteCommand: shellArgv([shell, "-s", "--", ...scriptArgs]), requiresStdin: true, invocationKind: "helper", stdinPrefix: shellScriptStdinPrefix() };
 }
 
 function buildShellStringCommand(args: string[]): ParsedSshArgs {
   const parsed = parseShellStringOperationArgs(args, "ssh shell");
-  return { remoteCommand: shellArgv([parsed.shell, "-c", parsed.command]), requiresStdin: false, invocationKind: "helper" };
+  return { remoteCommand: shellArgv([parsed.shell, "-c", shellScriptWithCompatibility(parsed.command)]), requiresStdin: false, invocationKind: "helper" };
 }
 
 function podApplyPatchStdinWrapper(): { prefix: string; suffix: string } {