Fix #5603 - account for file extension in file name length

CHANGELOG.md

@@ -71,6 +71,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We fixed an issue where the side pane was not remembering its position. [#5615](https://github.com/JabRef/jabref/issues/5615)
 - We fixed an issue where JabRef could not interact with [Oracle XE](https://www.oracle.com/de/database/technologies/appdev/xe.html) in the [shared SQL database setup](https://docs.jabref.org/collaborative-work/sqldatabase).
 - We fixed an issue where the toolbar icons were hidden on smaller screens.
+- We fixed an issue where renaming referenced files for bib entries with long titles was not possible. [#5603](https://github.com/JabRef/jabref/issues/5603)
 
 ### Removed
 

src/main/java/org/jabref/logic/util/io/FileUtil.java

@@ -79,7 +79,7 @@ public static String getValidFileName(String fileName) {
 
         if (nameWithoutExtension.length() > MAXIMUM_FILE_NAME_LENGTH) {
             Optional<String> extension = getFileExtension(fileName);
-            String shortName = nameWithoutExtension.substring(0, MAXIMUM_FILE_NAME_LENGTH);
+            String shortName = nameWithoutExtension.substring(0, MAXIMUM_FILE_NAME_LENGTH - extension.map(s -> s.length() + 1).orElse(0));
             LOGGER.info(String.format("Truncated the too long filename '%s' (%d characters) to '%s'.", fileName, fileName.length(), shortName));
             return extension.map(s -> shortName + "." + s).orElse(shortName);
         }

src/test/java/org/jabref/logic/util/io/FileUtilTest.java

@@ -343,7 +343,7 @@ void validFilenameWithoutExtension() {
 
     @Test
     void validFilenameShouldBeMaximum255Chars() {
-        String longestValidFilename = Stream.generate(() -> String.valueOf('1')).limit(FileUtil.MAXIMUM_FILE_NAME_LENGTH).collect(Collectors.joining()) + ".pdf";
+        String longestValidFilename = Stream.generate(() -> String.valueOf('1')).limit(FileUtil.MAXIMUM_FILE_NAME_LENGTH - 4).collect(Collectors.joining()) + ".pdf";
         String longerFilename = Stream.generate(() -> String.valueOf('1')).limit(260).collect(Collectors.joining()) + ".pdf";
         assertEquals(longestValidFilename, FileUtil.getValidFileName(longerFilename));
     }