Unicode conversion bibtexkey (#2720)

* Avoid unicode conversion for the key field in the main table

* Avoid unicode conversion for key field internally

* Fix changelog entry

CHANGELOG.md

@@ -65,6 +65,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - Improved author handling in MS-Office Import/Export
 - The `day` part of the biblatex `date` field is now exported to the corresponding `day` field in MS-Office XML. [#2691](https://github.com/JabRef/jabref/issues/2691)
 - Single underscores are not converted during the LaTeX to unicode conversion, which does not follow the rules of LaTeX, but is what users require. [#2664](https://github.com/JabRef/jabref/issues/2664)
+- The bibtexkey field is not converted to unicode 
 
 ### Fixed
  - We fixed an issue of duplicate keys after using a fetcher, e.g., DOI or ISBN [#2867](https://github.com/JabRef/jabref/issues/2687)

src/main/java/org/jabref/gui/maintable/MainTableColumn.java

@@ -107,7 +107,7 @@ public Object getColumnValue(BibEntry entry) {
             result = toUnicode.format(MainTableNameFormatter.formatName(result));
         }
 
-        if (result != null) {
+        if (result != null && !BibEntry.KEY_FIELD.equals(columnName)) {
             result = toUnicode.format(result).trim();
         }
 

src/main/java/org/jabref/model/entry/BibEntry.java

@@ -824,6 +824,11 @@ public Optional<String> getLatexFreeField(String name) {
             return Optional.empty();
         } else if (latexFreeFields.containsKey(name)) {
             return Optional.ofNullable(latexFreeFields.get(toLowerCase(name)));
+        } else if (KEY_FIELD.equals(name)) {
+            // the key field should not be converted
+            Optional<String> citeKey = getCiteKeyOptional();
+            latexFreeFields.put(name, citeKey.get());
+            return citeKey;
         } else {
             String latexFreeField = LatexToUnicodeAdapter.format(getField(name).get()).intern();
             latexFreeFields.put(name, latexFreeField);