debugger, errors: migrate to use internal/errors.js

doc/api/errors.md

@@ -575,9 +575,19 @@ found [here][online].
 [domains]: domain.html
 [event emitter-based]: events.html#events_class_eventemitter
 [file descriptors]: https://en.wikipedia.org/wiki/File_descriptor
+[Node.js Error Codes]: #nodejs-error-codes
 [online]: http://man7.org/linux/man-pages/man3/errno.3.html
 [stream-based]: stream.html
 [syscall]: http://man7.org/linux/man-pages/man2/syscall.2.html
 [try-catch]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch
 [V8's stack trace API]: https://github.com/v8/v8/wiki/Stack-Trace-API
 [vm]: vm.html
+
+<a id="nodejs-error-codes"></a>
+## Node.js Error Codes
+
+<a id="ERR_UNKNOWN_DEBUGGER_STATE"></a>
+### ERR_UNKNOWN_DEBUGGER_STATE
+
+The `'ERR_UNKNOWN_DEBUGGER_STATE'` error code is used to identify that the state
+of the debugger is not known, possibly set by code outside the debugger module.

lib/_debugger.js

@@ -11,6 +11,7 @@ const inherits = util.inherits;
 const assert = require('assert');
 const spawn = require('child_process').spawn;
 const Buffer = require('buffer').Buffer;
+const errors = require('internal/errors');
 
 exports.start = function(argv, stdin, stdout) {
   argv || (argv = process.argv.slice(2));
@@ -126,7 +127,7 @@ Protocol.prototype.execute = function(d) {
       break;
 
     default:
-      throw new Error('Unknown state');
+      throw new errors.Error('ERR_UNKNOWN_DEBUGGER_STATE');
   }
 };
 

lib/internal/errors.js

@@ -86,3 +86,4 @@ module.exports = exports = {
 // Note: Please try to keep these in alphabetical order
 E('ERR_ASSERTION', (msg) => msg);
 // Add new errors from here...
+E('ERR_UNKNOWN_DEBUGGER_STATE', 'Unknown state');

test/parallel/test-debug-protocol-execute.js

@@ -1,6 +1,6 @@
 'use strict';
 
-require('../common');
+const common = require('../common');
 const assert = require('assert');
 const debug = require('_debugger');
 
@@ -16,5 +16,5 @@ assert.strictEqual(protocol.res.body, undefined);
 protocol.state = 'sterrance';
 assert.throws(
   () => { protocol.execute('grumblecakes'); },
-  /^Error: Unknown state$/
+  common.expectsError('ERR_UNKNOWN_DEBUGGER_STATE', Error)
 );