repl: fix error message printing

addaleax · richardlau · commit 70e094a26b54 · 2021-12-14T15:32:15.000Z
The REPL implementation would strip away the first and last character of a formatted error message if it ended with `]` (but with the obviously missing check for a starting `]`), leading to things like `Uncaught rror: foo[a` being printed for input like `Error: foo[a]`. Refs: #22436 PR-URL: #38209 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
diff --git a/lib/repl.js b/lib/repl.js
@@ -566,7 +566,7 @@ function REPLServer(prompt,
         errStack = self.writer(e);
 
         // Remove one line error braces to keep the old style in place.
-        if (errStack[errStack.length - 1] === ']') {
+        if (errStack[0] === '[' && errStack[errStack.length - 1] === ']') {
           errStack = errStack.slice(1, -1);
         }
       }
diff --git a/test/parallel/test-repl-pretty-stack-custom-writer.js b/test/parallel/test-repl-pretty-stack-custom-writer.js
@@ -0,0 +1,23 @@
+'use strict';
+require('../common');
+const { PassThrough } = require('stream');
+const assert = require('assert');
+const repl = require('repl');
+
+{
+  const input = new PassThrough();
+  const output = new PassThrough();
+
+  const r = repl.start({
+    prompt: '',
+    input,
+    output,
+    writer: String,
+    terminal: false,
+    useColors: false
+  });
+
+  r.write('throw new Error("foo[a]")\n');
+  r.close();
+  assert.strictEqual(output.read().toString(), 'Uncaught Error: foo[a]\n');
+}

Original file line number	Diff line number	Diff line change
`@@ -566,7 +566,7 @@ function REPLServer(prompt,`
`566`	`566`	`errStack = self.writer(e);`
`567`	`567`
`568`	`568`	`// Remove one line error braces to keep the old style in place.`
`569`		`- if (errStack[errStack.length - 1] === ']') {`
	`569`	`+ if (errStack[0] === '[' && errStack[errStack.length - 1] === ']') {`
`570`	`570`	`errStack = errStack.slice(1, -1);`
`571`	`571`	`}`
`572`	`572`	`}`