chore: warn against using globally scoped install (#13196)

packages/playwright-core/src/cli/cli.ts

@@ -32,7 +32,7 @@ import { BrowserType } from '../client/browserType';
 import { BrowserContextOptions, LaunchOptions } from '../client/types';
 import { spawn } from 'child_process';
 import { registry, Executable } from '../utils/registry';
-import { spawnAsync, getPlaywrightVersion } from '../utils/utils';
+import { spawnAsync, getPlaywrightVersion, wrapInASCIIBox } from '../utils/utils';
 import { writeDockerVersion } from '../utils/dependencies';
 import { launchGridAgent } from '../grid/gridAgent';
 import { GridServer, GridFactory } from '../grid/gridServer';
@@ -115,6 +115,27 @@ program
     .option('--with-deps', 'install system dependencies for browsers')
     .option('--force', 'force reinstall of stable browser channels')
     .action(async function(args: string[], options: { withDeps?: boolean, force?: boolean }) {
+      const isLikelyNpxGlobal = process.argv.length >= 2 && process.argv[1].includes('_npx');
+      if (isLikelyNpxGlobal) {
+        console.error(wrapInASCIIBox([
+          `WARNING: It looks like you are running 'npx playwright install' without first`,
+          `installing your project's dependencies.`,
+          ``,
+          `To avoid unexpected behavior, please install your dependencies first, and`,
+          `then run Playwright's install command:`,
+          ``,
+          `    npm install`,
+          `    npx playwright install`,
+          ``,
+          `If your project does not yet depend on Playwright, first install the`,
+          `applicable npm package (most commonly @playwright/test), and`,
+          `then run Playwright's install command to download the browsers:`,
+          ``,
+          `    npm install @playwright/test`,
+          `    npx playwright install`,
+          ``,
+        ].join('\n'), 1));
+      }
       try {
         if (!args.length) {
           const executables = registry.defaultExecutables();