Mark OOSTyle as invalid if no defaultStyle

CHANGELOG.md

@@ -16,6 +16,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We added a short DOI field formatter which shortens DOI to more human-readable form. [koppor#343](https://github.com/koppor/jabref/issues/343)
 - We improved the display of group memberships by adding multiple colored bars if the entry belongs to more than one group. [#4574](https://github.com/JabRef/jabref/issues/4574)
 - We added an option to show the preview as an extra tab in the entry editor (instead of in a split view). [#5244](https://github.com/JabRef/jabref/issues/5244)
+- A custom Open/LibreOffice jstyle file now requires a layout line for the entry type `default` [#5452](https://github.com/JabRef/jabref/issues/5452)
 
 ### Fixed
 
@@ -43,6 +44,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We fixed some display errors in the preferences dialog and replaced some of the controls [#5033](https://github.com/JabRef/jabref/pull/5033) [#5047](https://github.com/JabRef/jabref/pull/5047) [#5062](https://github.com/JabRef/jabref/pull/5062) [#5141](https://github.com/JabRef/jabref/pull/5141) [#5185](https://github.com/JabRef/jabref/pull/5185) [#5265](https://github.com/JabRef/jabref/pull/5265) [#5315](https://github.com/JabRef/jabref/pull/5315) [#5360](https://github.com/JabRef/jabref/pull/5360)
 - We fixed an exception which occurred when trying to import entries without an open library. [#5447](https://github.com/JabRef/jabref/issues/5447) 
 - After successful import of one or multiple bib entries the main table scrolls to the first imported entry [#5383](https://github.com/JabRef/jabref/issues/5383)
+- We fixed an exception which occurred when an invalid jstyle was loaded. [#5452](https://github.com/JabRef/jabref/issues/5452)
 
 
 ### Removed

src/main/java/org/jabref/gui/openoffice/StyleSelectDialogView.java

@@ -24,6 +24,7 @@
 import org.jabref.logic.openoffice.StyleLoader;
 import org.jabref.logic.util.TestEntry;
 import org.jabref.model.database.BibDatabaseContext;
+import org.jabref.model.entry.types.StandardEntryType;
 import org.jabref.preferences.PreferencesService;
 
 import com.airhacks.afterburner.views.ViewLoader;
@@ -118,8 +119,8 @@ private void initialize() {
 
         EasyBind.subscribe(viewModel.selectedItemProperty(), style -> {
             tvStyles.getSelectionModel().select(style);
-            previewArticle.setLayout(new TextBasedPreviewLayout(style.getStyle().getDefaultBibLayout()));
-            previewBook.setLayout(new TextBasedPreviewLayout(style.getStyle().getDefaultBibLayout()));
+            previewArticle.setLayout(new TextBasedPreviewLayout(style.getStyle().getReferenceFormat(StandardEntryType.Article)));
+            previewBook.setLayout(new TextBasedPreviewLayout(style.getStyle().getReferenceFormat(StandardEntryType.Book)));
         });
     }
 

src/main/java/org/jabref/logic/openoffice/OOBibStyle.java

@@ -122,6 +122,7 @@ public class OOBibStyle implements Comparable<OOBibStyle> {
     private File styleFile;
     private long styleFileModificationTime = Long.MIN_VALUE;
     private String localCopy;
+    private boolean isDefaultLayoutPresent;
     public OOBibStyle(File styleFile, LayoutFormatterPreferences prefs,
             Charset encoding) throws IOException {
         this.prefs = Objects.requireNonNull(prefs);
@@ -321,13 +322,11 @@ private void readFormatFile(Reader in) throws IOException {
             }
 
         }
-
         // Set validity boolean based on whether we found anything interesting
         // in the file:
-        if (mode != BibStyleMode.NONE) {
+        if ((mode != BibStyleMode.NONE) && isDefaultLayoutPresent) {
             valid = true;
         }
-
     }
 
     /**
@@ -350,11 +349,11 @@ private void handleStructureLine(String line) {
         int index = line.indexOf('=');
         if ((index > 0) && (index < (line.length() - 1))) {
             String formatString = line.substring(index + 1);
-            boolean setDefault = line.substring(0, index).equals(OOBibStyle.DEFAULT_MARK);
+            isDefaultLayoutPresent = line.substring(0, index).equals(OOBibStyle.DEFAULT_MARK);
             EntryType type = EntryTypeFactory.parse(line.substring(0, index));
             try {
                 Layout layout = new LayoutHelper(new StringReader(formatString), this.prefs).getLayoutFromText();
-                if (setDefault) {
+                if (isDefaultLayoutPresent) {
                     defaultBibLayout = layout;
                 } else {
                     bibLayout.put(type, layout);