Add fallback

CHANGELOG.md

@@ -41,6 +41,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - After importing, now all imported entries are marked. [#13535](https://github.com/JabRef/jabref/pull/13535)
 - The URL integrity check now checks the complete URL syntax. [#14370](https://github.com/JabRef/jabref/pull/14370)
 - <kbd>Tab</kbd> in the last text field of a tab moves the focus to the next tab in the entry editor. [#11937](https://github.com/JabRef/jabref/issues/11937)
+- When pasting invalid BibTeX data, the content is now pasted as `@Misc` with the raw data in the `note` field. [#14520](https://github.com/JabRef/jabref/pull/14520)
 - We changed fixed-value ComboBoxes to SearchableComboBox for better usability. [#14083](https://github.com/JabRef/jabref/issues/14083)
 
 ### Fixed

jabgui/src/main/java/org/jabref/gui/LibraryTab.java

@@ -92,6 +92,8 @@
 import org.jabref.model.entry.event.EntriesEventSource;
 import org.jabref.model.entry.event.FieldChangedEvent;
 import org.jabref.model.entry.field.FieldFactory;
+import org.jabref.model.entry.field.StandardField;
+import org.jabref.model.entry.types.StandardEntryType;
 import org.jabref.model.groups.GroupTreeNode;
 import org.jabref.model.search.query.SearchQuery;
 import org.jabref.model.util.FileUpdateMonitor;
@@ -894,7 +896,10 @@ private List<BibEntry> handleNonBibTeXStringData(String data) {
             } else {
                 dialogService.showErrorDialogAndWait(exception);
             }
-            return List.of();
+            BibEntry fallBack = new BibEntry(StandardEntryType.Misc)
+                    .withField(StandardField.COMMENT, data)
+                    .withChanged(true);
+            return List.of(fallBack);
         }
     }
 

jabgui/src/main/java/org/jabref/gui/externalfiles/ImportHandler.java

@@ -64,6 +64,7 @@
 
 import com.airhacks.afterburner.injection.Injector;
 import com.google.common.annotations.VisibleForTesting;
+import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -391,15 +392,20 @@ private void generateKeys(List<BibEntry> entries) {
         entries.forEach(keyGenerator::generateAndSetKey);
     }
 
-    public List<BibEntry> handleBibTeXData(String entries) {
+    public @NonNull List<@NonNull BibEntry> handleBibTeXData(@NonNull String entries) {
+        if (!entries.contains("@")) {
+            LOGGER.debug("Seems not to be BibTeX data: {}", entries);
+            return List.of();
+        }
         BibtexParser parser = new BibtexParser(preferences.getImportFormatPreferences(), fileUpdateMonitor);
         try {
             List<BibEntry> result = parser.parseEntries(new ByteArrayInputStream(entries.getBytes(StandardCharsets.UTF_8)));
             Collection<BibtexString> stringConstants = parser.getStringValues();
             importStringConstantsWithDuplicateCheck(stringConstants);
             return result;
         } catch (ParseException ex) {
-            LOGGER.error("Could not paste", ex);
+            LOGGER.info("Data could not be interpreted as Bib(La)TeX", ex);
+            dialogService.notify(Localization.lang("Failed to parse Bib(La)TeX: %0", ex.getLocalizedMessage()));
             return List.of();
         }
     }