From a2a824ed01dc1bd817d753d7df9a84503d10204f Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 27 Mar 2019 00:00:13 +0100
Subject: [PATCH] Don't accidentally use an empty `hash` value when comparing
 `preEvaluatedFonts` in `PartialEvaluator.loadFont`

Note that `PartialEvaluator.preEvaluateFont` will return an empty string when no hash was computed. This will complete short-circuit the `fontAlias` comparison in `PartialEvaluator.loadFont`, since fonts which are totally different will then match if their `hash`es are empty.
---
 src/core/evaluator.js | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/core/evaluator.js b/src/core/evaluator.js
index 06951cdee..df5b1c1d7 100644
--- a/src/core/evaluator.js
+++ b/src/core/evaluator.js
@@ -695,20 +695,19 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       var fontCapability = createPromiseCapability();
 
       var preEvaluatedFont = this.preEvaluateFont(font);
-      var descriptor = preEvaluatedFont.descriptor;
+      const { descriptor, hash, } = preEvaluatedFont;
 
       var fontRefIsRef = isRef(fontRef), fontID;
       if (fontRefIsRef) {
         fontID = fontRef.toString();
       }
 
-      if (isDict(descriptor)) {
+      if (hash && isDict(descriptor)) {
         if (!descriptor.fontAliases) {
           descriptor.fontAliases = Object.create(null);
         }
-
         var fontAliases = descriptor.fontAliases;
-        var hash = preEvaluatedFont.hash;
+
         if (fontAliases[hash]) {
           var aliasFontRef = fontAliases[hash].aliasRef;
           if (fontRefIsRef && aliasFontRef &&
@@ -785,7 +784,6 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
 
         try {
           // error, but it's still nice to have font type reported
-          var descriptor = preEvaluatedFont.descriptor;
           var fontFile3 = descriptor && descriptor.get('FontFile3');
           var subtype = fontFile3 && fontFile3.get('Subtype');
           var fontType = getFontType(preEvaluatedFont.type,