From 12d60e0acf1d1fe3130df971b397555df4003136 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sat, 3 Sep 2022 22:55:24 +0200
Subject: [PATCH] Don't allow `adjustToUnicode` to extend a built-in /ToUnicode
 map (issue 15352)

Given that the change in PR 13393 was slightly speculative, given the lack of test-cases, let's just revert part of that to fix the referenced issue.
Based on a quick look at old issues and existing test-cases, it seems that most (if not all) PDF documents that benefit from using the font-data in this way lack any /ToUnicode maps which should mean that they're unaffected by these changes.
---
 src/core/fonts.js             | 9 ++++-----
 test/pdfs/issue15352.pdf.link | 1 +
 test/test_manifest.json       | 8 ++++++++
 3 files changed, 13 insertions(+), 5 deletions(-)
 create mode 100644 test/pdfs/issue15352.pdf.link

diff --git a/src/core/fonts.js b/src/core/fonts.js
index 9fac0c727..372fc81ea 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -137,6 +137,9 @@ function adjustToUnicode(properties, builtInEncoding) {
   if (properties.isInternalFont) {
     return;
   }
+  if (properties.hasIncludedToUnicodeMap) {
+    return; // The font dictionary has a `ToUnicode` entry.
+  }
   if (builtInEncoding === properties.defaultEncoding) {
     return; // No point in trying to adjust `toUnicode` if the encodings match.
   }
@@ -146,11 +149,7 @@ function adjustToUnicode(properties, builtInEncoding) {
   const toUnicode = [],
     glyphsUnicodeMap = getGlyphsUnicode();
   for (const charCode in builtInEncoding) {
-    if (properties.hasIncludedToUnicodeMap) {
-      if (properties.toUnicode.has(charCode)) {
-        continue; // The font dictionary has a `ToUnicode` entry.
-      }
-    } else if (properties.hasEncoding) {
+    if (properties.hasEncoding) {
       if (
         properties.differences.length === 0 ||
         properties.differences[charCode] !== undefined
diff --git a/test/pdfs/issue15352.pdf.link b/test/pdfs/issue15352.pdf.link
new file mode 100644
index 000000000..eba137591
--- /dev/null
+++ b/test/pdfs/issue15352.pdf.link
@@ -0,0 +1 @@
+https://web.archive.org/web/20220903205442/https://pdf.cdn.readpaper.com/aiKnowledge/pdf/2022-05-06/d55ec560f4c142c3973abc66397d1822-/userUpload/d0edf452a85821acf41cbfa0a6f2f2ac.pdf
diff --git a/test/test_manifest.json b/test/test_manifest.json
index 0318eb54f..186bfae2a 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -2860,6 +2860,14 @@
        "link": false,
        "type": "text"
     },
+    {  "id": "issue15352",
+       "file": "pdfs/issue15352.pdf",
+       "md5": "d0edf452a85821acf41cbfa0a6f2f2ac",
+       "rounds": 1,
+       "link": true,
+       "lastPage": 1,
+       "type": "text"
+    },
     {  "id": "issue6962",
        "file": "pdfs/issue6962.pdf",
        "md5": "d40e871ecca68baf93114bd28c782148",