repl: avoid crashing from null and undefined errors

When `throw undefined` or `throw null` is executed, the REPL crashes. This change does a check for `null|undefined` before accessing an error's properties to prevent crashing. Fixes: #16545Fixes: #16607 PR-URL: #16574 Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Lance Ball <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Sakthipriyan Vairamani <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Jeremiah Senkpiel <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Gireesh Punathil <[email protected]>

Author: priyank-p

lib/repl.js

@@ -257,12 +257,13 @@ function REPLServer(prompt,
 }
 }catch(e){
 err=e;
-if(err.message==='Script execution interrupted.'){
+
+if(err&&err.message==='Script execution interrupted.'){
 // The stack trace for this case is not very useful anyway.
 Object.defineProperty(err,'stack',{value: ''});
 }
 
-if(err&&process.domain){
+if(process.domain){
 debug('not recoverable, send to domain');
 process.domain.emit('error',err);
 process.domain.exit();

test/parallel/test-repl-throw-null-or-undefined.js

@@ -0,0 +1,18 @@
+'use strict';
+require('../common');
+
+// This test ensures that the repl does not
+// crash or emit error when throwing `null|undefined`
+// ie `throw null` or `throw undefined`
+
+constassert=require('assert');
+constrepl=require('repl');
+
+constr=repl.start();
+
+assert.doesNotThrow(()=>{
+r.write('throw null\n');
+r.write('throw undefined\n');
+},TypeError,'repl crashes/throw error on `throw null|undefined`');
+
+r.write('.exit\n');