repl: processTopLevelAwait fallback error handling

PR-URL: #39290 Reviewed-By: Guy Bedford <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: ejose19

lib/internal/repl/await.js

@@ -184,7 +184,10 @@ function processTopLevelAwait(src){
 '^\n\n'+RegExpPrototypeSymbolReplace(/\([^)]+\)/,e.message,'');
 // V8 unexpected token errors include the token string.
 if(StringPrototypeEndsWith(message,'Unexpected token'))
-message+=" '"+src[e.pos-wrapPrefix.length]+"'";
+message+=" '"+
+// Wrapper end may cause acorn to report error position after the source
+(src[e.pos-wrapPrefix.length]??src[src.length-1])+
+"'";
 // eslint-disable-next-line no-restricted-syntax
 thrownewSyntaxError(message);
 }

lib/repl.js

@@ -78,6 +78,7 @@ const{
  ReflectApply,
  RegExp,
  RegExpPrototypeExec,
+ RegExpPrototypeSymbolReplace,
  RegExpPrototypeTest,
  SafeSet,
  SafeWeakSet,
@@ -434,8 +435,39 @@ function REPLServer(prompt,
 awaitPromise=true;
 }
 }catch(e){
-decorateErrorStack(e);
-err=e;
+letrecoverableError=false;
+if(e.name==='SyntaxError'){
+letparentURL;
+try{
+const{ pathToFileURL }=require('url');
+// Adding `/repl` prevents dynamic imports from loading relative
+// to the parent of `process.cwd()`.
+parentURL=pathToFileURL(path.join(process.cwd(),'repl')).href;
+}catch{
+}
+
+// Remove all "await"s and attempt running the script
+// in order to detect if error is truly non recoverable
+constfallbackCode=RegExpPrototypeSymbolReplace(/\bawait\b/g,code,'');
+try{
+vm.createScript(fallbackCode,{
+filename: file,
+displayErrors: true,
+importModuleDynamically: async(specifier)=>{
+returnasyncESM.ESMLoader.import(specifier,parentURL);
+}
+});
+}catch(fallbackError){
+if(isRecoverableError(fallbackError,fallbackCode)){
+recoverableError=true;
+err=newRecoverable(e);
+}
+}
+}
+if(!recoverableError){
+decorateErrorStack(e);
+err=e;
+}
 }
 }
 

test/parallel/test-repl-top-level-await.js

@@ -152,6 +152,36 @@ async function ordinaryTests(){
 'Unexpected token \'.\'',
 ],
 ],
+['for (const x of [1,2,3]){\nawait x\n}',[
+'for (const x of [1,2,3]){\r',
+'... await x\r',
+'... }\r',
+'undefined',
+]],
+['for (const x of [1,2,3]){\nawait x;\n}',[
+'for (const x of [1,2,3]){\r',
+'... await x;\r',
+'... }\r',
+'undefined',
+]],
+['for await (const x of [1,2,3]){\nconsole.log(x)\n}',[
+'for await (const x of [1,2,3]){\r',
+'... console.log(x)\r',
+'... }\r',
+'1',
+'2',
+'3',
+'undefined',
+]],
+['for await (const x of [1,2,3]){\nconsole.log(x);\n}',[
+'for await (const x of [1,2,3]){\r',
+'... console.log(x);\r',
+'... }\r',
+'1',
+'2',
+'3',
+'undefined',
+]],
 ];
 
 for(const[input,expected=[`${input}\r`],options={}]oftestCases){