fix(dlx): print help message when no arguments are provided (#10690)

* fix(dlx): print help message on calling pnpm dlx without arguments

Running `pnpm dlx` with no arguments would crash Node.js with a
TypeError as it attempted to call `.indexOf()` on an undefined variable.
This commit adds a guard clause and displays the help message instead
and exits gracefully.

Fixes #10633

* refactor: dlx

---------

Co-authored-by: Zoltan Kochan <z@kochan.io>

.changeset/twenty-parks-end.md

@@ -0,0 +1,6 @@
+---
+"@pnpm/plugin-commands-script-runners": patch
+"pnpm": patch
+---
+
+Print help message on running pnpm dlx without arguments and exit.

exec/plugin-commands-script-runners/src/dlx.ts

@@ -87,7 +87,10 @@ export type DlxCommandOptions = {
 export async function handler (
   opts: DlxCommandOptions,
   [command, ...args]: string[]
-): Promise<{ exitCode: number }> {
+): Promise<{ exitCode: number, output?: string }> {
+  if (!command && (!opts.package || opts.package.length === 0)) {
+    return { exitCode: 1, output: help() }
+  }
   const pkgs = opts.package ?? [command]
   const fullMetadata = (
     (

pnpm/test/dlx.ts

@@ -299,6 +299,17 @@ test('dlx uses the node version specified by --package=node@runtime:<version>',
   }
 })
 
+test('dlx without arguments prints help text and exits with 1', () => {
+  prepareEmpty()
+
+  const result = execPnpmSync(['dlx'])
+
+  expect(result.status).toBe(1)
+
+  const output = result.stdout.toString()
+  expect(output).toMatch(/Run a package in a temporary environment\./)
+})
+
 describeOnLinuxOnly('dlx with supportedArchitectures CLI options', () => {
   type CPU = 'arm64' | 'x64'
   type LibC = 'glibc' | 'musl'