repl: don't terminate on null thrown

Previous behavior was to assume an error is a proper error in the repl module. A check was added to not terminate the process on thrown repl errors that are `null` or `undefined`. PR-URL: #14306Fixes: #12373 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Timothy Gu <[email protected]> Reviewed-By: Jeremiah Senkpiel <[email protected]> Reviewed-By: Colin Ihrig <[email protected]

Author: Benjamin Gruenbaum

lib/repl.js

@@ -282,17 +282,23 @@ function REPLServer(prompt,
 self._domain.on('error',functiondebugDomainError(e){
 debug('domain error');
 consttop=replMap.get(self);
+
 internalUtil.decorateErrorStack(e);
+constisError=internalUtil.isError(e);
 if(einstanceofSyntaxError&&e.stack){
 // remove repl:line-number and stack trace
 e.stack=e.stack
 .replace(/^repl:\d+\r?\n/,'')
 .replace(/^\s+at\s.*\n?/gm,'');
-}elseif(e.stack&&self.replMode===exports.REPL_MODE_STRICT){
+}elseif(isError&&self.replMode===exports.REPL_MODE_STRICT){
 e.stack=e.stack.replace(/(\s+at\s+repl:)(\d+)/,
 (_,pre,line)=>pre+(line-1));
 }
-top.outputStream.write((e.stack||e)+'\n');
+if(isError&&e.stack){
+top.outputStream.write(`${e.stack}\n`);
+}else{
+top.outputStream.write(`Thrown: ${String(e)}\n`);
+}
 top.bufferedCommand='';
 top.lines.level=[];
 top.displayPrompt();

test/parallel/test-repl-null-thrown.js

@@ -0,0 +1,24 @@
+'use strict';
+require('../common');
+constrepl=require('repl');
+constassert=require('assert');
+constStream=require('stream');
+
+constoutput=newStream();
+lettext='';
+output.write=output.pause=output.resume=function(buf){
+text+=buf.toString();
+};
+
+constreplserver=repl.start({
+output: output,
+input: process.stdin
+});
+
+replserver.emit('line','process.nextTick(() =>{throw null})');
+replserver.emit('line','.exit');
+
+setTimeout(()=>{
+console.log(text);
+assert(text.includes('Thrown: null'));
+},0);