fix(coding-agent): run legacy WSL bash commands via stdin

closes #5893

packages/coding-agent/src/core/resolve-config-value.ts

@@ -152,11 +152,13 @@ export function resolveConfigValue(config: string, env?: Record<string, string>)
 
 function executeWithConfiguredShell(command: string): { executed: boolean; value: string | undefined } {
 	try {
-		const { shell, args } = getShellConfig();
-		const result = spawnSync(shell, [...args, command], {
+		const { shell, args, commandTransport } = getShellConfig();
+		const commandFromStdin = commandTransport === "stdin";
+		const result = spawnSync(shell, commandFromStdin ? args : [...args, command], {
 			encoding: "utf-8",
+			input: commandFromStdin ? command : undefined,
 			timeout: 10000,
-			stdio: ["ignore", "pipe", "ignore"],
+			stdio: [commandFromStdin ? "pipe" : "ignore", "pipe", "ignore"],
 			shell: false,
 			windowsHide: true,
 		});

packages/coding-agent/src/core/tools/bash.ts

@@ -66,7 +66,7 @@ export interface BashOperations {
 export function createLocalBashOperations(options?: { shellPath?: string }): BashOperations {
 	return {
 		exec: async (command, cwd, { onData, signal, timeout, env }) => {
-			const { shell, args } = getShellConfig(options?.shellPath);
+			const shellConfig = getShellConfig(options?.shellPath);
 			try {
 				await fsAccess(cwd, constants.F_OK);
 			} catch {
@@ -76,13 +76,18 @@ export function createLocalBashOperations(options?: { shellPath?: string }): Bas
 				throw new Error("aborted");
 			}
 
-			const child = spawn(shell, [...args, command], {
+			const commandFromStdin = shellConfig.commandTransport === "stdin";
+			const child = spawn(shellConfig.shell, commandFromStdin ? shellConfig.args : [...shellConfig.args, command], {
 				cwd,
 				detached: process.platform !== "win32",
 				env: env ?? getShellEnv(),
-				stdio: ["ignore", "pipe", "pipe"],
+				stdio: [commandFromStdin ? "pipe" : "ignore", "pipe", "pipe"],
 				windowsHide: true,
 			});
+			if (commandFromStdin) {
+				child.stdin?.on("error", () => {});
+				child.stdin?.end(command);
+			}
 			if (child.pid) trackDetachedChildPid(child.pid);
 			let timedOut = false;
 			let timeoutHandle: NodeJS.Timeout | undefined;

packages/coding-agent/src/utils/shell.ts

@@ -6,11 +6,21 @@ import { getBinDir } from "../config.ts";
 export interface ShellConfig {
 	shell: string;
 	args: string[];
+	commandTransport?: "argv" | "stdin";
 }
 
 /**
  * Find bash executable on PATH (cross-platform)
  */
+function isLegacyWslBashPath(path: string): boolean {
+	const normalized = path.replace(/\//g, "\\").toLowerCase();
+	return /^[a-z]:\\windows\\(?:system32|sysnative)\\bash\.exe$/.test(normalized);
+}
+
+function getBashShellConfig(shell: string): ShellConfig {
+	return isLegacyWslBashPath(shell) ? { shell, args: ["-s"], commandTransport: "stdin" } : { shell, args: ["-c"] };
+}
+
 function findBashOnPath(): string | null {
 	if (process.platform === "win32") {
 		// Windows: Use 'where' and verify file exists (where can return non-existent paths)
@@ -58,7 +68,7 @@ export function getShellConfig(customShellPath?: string): ShellConfig {
 	// 1. Check user-specified shell path
 	if (customShellPath) {
 		if (existsSync(customShellPath)) {
-			return { shell: customShellPath, args: ["-c"] };
+			return getBashShellConfig(customShellPath);
 		}
 		throw new Error(`Custom shell path not found: ${customShellPath}`);
 	}
@@ -77,14 +87,14 @@ export function getShellConfig(customShellPath?: string): ShellConfig {
 
 		for (const path of paths) {
 			if (existsSync(path)) {
-				return { shell: path, args: ["-c"] };
+				return getBashShellConfig(path);
 			}
 		}
 
 		// 3. Fallback: search bash.exe on PATH (Cygwin, MSYS2, WSL, etc.)
 		const bashOnPath = findBashOnPath();
 		if (bashOnPath) {
-			return { shell: bashOnPath, args: ["-c"] };
+			return getBashShellConfig(bashOnPath);
 		}
 
 		throw new Error(
@@ -98,12 +108,12 @@ export function getShellConfig(customShellPath?: string): ShellConfig {
 
 	// Unix: try /bin/bash, then bash on PATH, then fallback to sh
 	if (existsSync("/bin/bash")) {
-		return { shell: "/bin/bash", args: ["-c"] };
+		return getBashShellConfig("/bin/bash");
 	}
 
 	const bashOnPath = findBashOnPath();
 	if (bashOnPath) {
-		return { shell: bashOnPath, args: ["-c"] };
+		return getBashShellConfig(bashOnPath);
 	}
 
 	return { shell: "sh", args: ["-c"] };