From 4df365256f54aa2cbc418c9386e4c24a61237ffd Mon Sep 17 00:00:00 2001
From: Ruben Bridgewater <ruben@bridgewater.de>
Date: Mon, 23 Sep 2019 08:14:35 +0200
Subject: [PATCH] buffer: improve .from() error details

This makes sure the original input is passed to the error in case
no matching inputs are found. Instead of passing along all values,
only valid or possibliy valid values are passed through. That way
invalid values end up in the error case with the original input.

PR-URL: https://github.com/nodejs/node/pull/29675
Reviewed-By: Rich Trott <rtrott@gmail.com>
---
 lib/buffer.js | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/lib/buffer.js b/lib/buffer.js
index 74d6511b35f59c..2bed199f5744dc 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -291,17 +291,21 @@ Buffer.from = function from(value, encodingOrOffset, length) {
       return fromArrayBuffer(value, encodingOrOffset, length);
 
     const valueOf = value.valueOf && value.valueOf();
-    if (valueOf !== null && valueOf !== undefined && valueOf !== value)
-      return Buffer.from(valueOf, encodingOrOffset, length);
+    if (valueOf != null &&
+        valueOf !== value &&
+        (typeof valueOf === 'string' || typeof valueOf === 'object')) {
+      return from(valueOf, encodingOrOffset, length);
+    }
 
     const b = fromObject(value);
     if (b)
       return b;
 
     if (typeof value[SymbolToPrimitive] === 'function') {
-      return Buffer.from(value[SymbolToPrimitive]('string'),
-                         encodingOrOffset,
-                         length);
+      const primitive = value[SymbolToPrimitive]('string');
+      if (typeof primitive === 'string') {
+        return fromString(primitive, encodingOrOffset);
+      }
     }
   }