inspector: warn when a file shadows node inspect

lib/internal/debugger/inspect.js

@@ -317,6 +317,34 @@ function parseInspectMode(args) {
   return { mode: 'interactive' };
 }
 
+// `node inspect` runs the debugger. If a file named after the command
+// (e.g. `inspect.js`) also exists in the current directory, the user may have
+// meant to run that file instead. That shadowing is otherwise silent, so emit
+// a warning. Refs: https://github.com/nodejs/node/issues/64111
+function warnIfShadowedByLocalFile() {
+  const command = process.argv[1];
+  if (typeof command !== 'string' || command.length === 0) return;
+
+  const { existsSync } = require('fs');
+  const { resolve } = require('path');
+  const cwd = process.cwd();
+
+  let candidate;
+  if (existsSync(resolve(cwd, `${command}.js`))) {
+    candidate = `${command}.js`;
+  } else if (existsSync(resolve(cwd, command))) {
+    candidate = command;
+  } else {
+    return;
+  }
+
+  process.emitWarning(
+    `'${process.argv0} ${command}' started the debugger; the file ` +
+    `'${candidate}' in the current directory was not run. To run it instead, ` +
+    `use '${process.argv0} ./${candidate}'.`,
+  );
+}
+
 function startInspect(argv = ArrayPrototypeSlice(process.argv, 2),
                       stdin = process.stdin,
                       stdout = process.stdout) {
@@ -343,6 +371,8 @@ function startInspect(argv = ArrayPrototypeSlice(process.argv, 2),
     return;
   }
 
+  warnIfShadowedByLocalFile();
+
   const options = parseInteractiveArgs(argv);
   const inspector = new NodeInspector(options, stdin, stdout);
 

test/parallel/test-debugger-shadowed-by-local-file.js

@@ -0,0 +1,35 @@
+'use strict';
+const common = require('../common');
+
+common.skipIfInspectorDisabled();
+
+const assert = require('assert');
+const fs = require('fs');
+
+const fixtures = require('../common/fixtures');
+const startCLI = require('../common/debugger');
+const tmpdir = require('../common/tmpdir');
+
+// When `node inspect` starts the debugger and a file named after the command
+// (e.g. `inspect.js`) exists in the current directory, a warning is emitted so
+// the shadowing is not silent.
+// Refs: https://github.com/nodejs/node/issues/64111
+tmpdir.refresh();
+fs.writeFileSync(tmpdir.resolve('inspect.js'), '// not run\n');
+
+const script = fixtures.path('debugger', 'three-lines.js');
+const cli = startCLI([script], [], { cwd: tmpdir.path });
+
+(async function() {
+  try {
+    await cli.waitForInitialBreak();
+    await cli.waitForPrompt();
+    assert.match(
+      cli.output,
+      /started the debugger; the file 'inspect\.js' in the current directory was not run/,
+    );
+  } finally {
+    const code = await cli.quit();
+    assert.strictEqual(code, 0);
+  }
+})().then(common.mustCall());