JabRef · koppor · Jul 13, 2026 · Jul 13, 2026 · Jul 13, 2026 · Jul 14, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 
 ### Added
 
+- Directory libraries now stay in sync with external file changes: creating, editing, deleting, or renaming `.yml`/`.md`/`.pdf` files in the opened folder updates the open library live, and renames keep the affected entries (selection and undo history survive). [#738](https://github.com/JabRef/jabref-koppor/pull/738)
 - We added "Open folder as library" (File menu): a folder of PDFs and Hayagriva sidecar files (`.yml`, or `.md` notes with a Hayagriva frontmatter) opens as a library, and it is reopened on the next start. PDFs without a sidecar appear right away and get their metadata extracted in the background. Edits are not yet written back to the files. [#737](https://github.com/JabRef/jabref-koppor/pull/737)
 - We added `jabkit git merge-driver`, a Git merge driver that merges `.bib` files semantically. [#16838](https://github.com/JabRef/jabref/pull/16838)
 

diff --git a/docs/requirements/directory-library.md b/docs/requirements/directory-library.md
@@ -34,4 +34,17 @@ the last-opened list and routed back through the directory-library opener.
 
 Needs: impl
 
+## External file changes appear live in an open directory library
+`req~directory-library.inbound-sync~2`
+
+While a directory library is open, external creation, modification, deletion, and renaming of
+`.yml`/`.yaml`/`.md`/`.pdf` files under its root must be reflected in the open library. Changed
+entries are updated in place (the entry identity is preserved), renames are detected via a
+grace window over the monitor's delete + create events and keep the affected entries, and files
+written by JabRef itself are recognized by fingerprint and not re-imported. All resulting
+database mutations carry a non-local event source so the future write-back direction can ignore
+them.
+
+Needs: impl
+
 <!-- markdownlint-disable-file MD022 -->
diff --git a/jabgui/src/main/java/org/jabref/gui/JabRefGUI.java b/jabgui/src/main/java/org/jabref/gui/JabRefGUI.java
@@ -34,7 +34,6 @@
 import org.jabref.gui.remote.CLIMessageHandler;
 import org.jabref.gui.theme.ThemeManager;
 import org.jabref.gui.util.DefaultFileUpdateMonitor;
-import org.jabref.gui.util.DirectoryMonitor;
 import org.jabref.gui.util.UiTaskExecutor;
 import org.jabref.gui.walkthrough.WalkthroughPane;
 import org.jabref.http.manager.HttpServerManager;
@@ -55,6 +54,7 @@
 import org.jabref.logic.search.sqlbased.IndexManager;
 import org.jabref.logic.search.sqlbased.PostgresServer;
 import org.jabref.logic.util.BuildInfo;
+import org.jabref.logic.util.DirectoryMonitor;
 import org.jabref.logic.util.FallbackExceptionHandler;
 import org.jabref.logic.util.HeadlessExecutorService;
 import org.jabref.logic.util.TaskExecutor;

diff --git a/jabgui/src/main/java/org/jabref/gui/LibraryTab.java b/jabgui/src/main/java/org/jabref/gui/LibraryTab.java
@@ -940,6 +940,10 @@ private void onClosed(Event event) {
         if (dataLoadingTask != null) {
             dataLoadingTask.cancel();
         }
+        if (bibDatabaseContext.getLocation() == DatabaseLocation.DIRECTORY) {
+            // Stops the directory watcher and shuts the synchronizer down
+            bibDatabaseContext.convertToLocalDatabase();
+        }
         if (bibDatabaseContext.getLocation() == DatabaseLocation.SHARED) {
             closeSharedDatabase(bibDatabaseContext);
         }

diff --git a/jabgui/src/main/java/org/jabref/gui/entryeditor/EntryEditor.java b/jabgui/src/main/java/org/jabref/gui/entryeditor/EntryEditor.java
@@ -36,14 +36,14 @@
 import org.jabref.gui.undo.RedoAction;
 import org.jabref.gui.undo.UndoAction;
 import org.jabref.gui.util.BaseDialog;
-import org.jabref.gui.util.DirectoryMonitor;
 import org.jabref.gui.util.DragDrop;
 import org.jabref.logic.ai.AiService;
 import org.jabref.logic.citation.SearchCitationsRelationsService;
 import org.jabref.logic.help.HelpFile;
 import org.jabref.logic.importer.EntryBasedFetcher;
 import org.jabref.logic.journals.JournalAbbreviationRepository;
 import org.jabref.logic.util.BuildInfo;
+import org.jabref.logic.util.DirectoryMonitor;
 import org.jabref.logic.util.TaskExecutor;
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.BibEntryTypesManager;

diff --git a/jabgui/src/main/java/org/jabref/gui/entryeditor/EntryEditorTabFactory.java b/jabgui/src/main/java/org/jabref/gui/entryeditor/EntryEditorTabFactory.java
@@ -13,10 +13,10 @@
 import org.jabref.gui.preview.PreviewPanel;
 import org.jabref.gui.undo.RedoAction;
 import org.jabref.gui.undo.UndoAction;
-import org.jabref.gui.util.DirectoryMonitor;
 import org.jabref.logic.citation.SearchCitationsRelationsService;
 import org.jabref.logic.journals.JournalAbbreviationRepository;
 import org.jabref.logic.util.BuildInfo;
+import org.jabref.logic.util.DirectoryMonitor;
 import org.jabref.logic.util.TaskExecutor;
 import org.jabref.model.entry.BibEntryTypesManager;
 import org.jabref.model.util.FileUpdateMonitor;

diff --git a/jabgui/src/main/java/org/jabref/gui/entryeditor/LatexCitationsTab.java b/jabgui/src/main/java/org/jabref/gui/entryeditor/LatexCitationsTab.java
@@ -20,8 +20,8 @@
 import org.jabref.gui.icon.IconTheme;
 import org.jabref.gui.preferences.GuiPreferences;
 import org.jabref.gui.texparser.CitationsDisplay;
-import org.jabref.gui.util.DirectoryMonitor;
 import org.jabref.logic.l10n.Localization;
+import org.jabref.logic.util.DirectoryMonitor;
 import org.jabref.model.entry.BibEntry;
 
 import com.tobiasdiez.easybind.EasyBind;

diff --git a/jabgui/src/main/java/org/jabref/gui/entryeditor/LatexCitationsTabViewModel.java b/jabgui/src/main/java/org/jabref/gui/entryeditor/LatexCitationsTabViewModel.java
@@ -27,10 +27,10 @@
 import org.jabref.gui.push.GuiPushToTeXstudio;
 import org.jabref.gui.texparser.CitationsDisplay;
 import org.jabref.gui.util.DirectoryDialogConfiguration;
-import org.jabref.gui.util.DirectoryMonitor;
 import org.jabref.gui.util.UiTaskExecutor;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.texparser.DefaultLatexParser;
+import org.jabref.logic.util.DirectoryMonitor;
 import org.jabref.logic.util.io.FileUtil;
 import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.entry.BibEntry;

diff --git a/jabgui/src/main/java/org/jabref/gui/importer/actions/OpenDirectoryLibraryAction.java b/jabgui/src/main/java/org/jabref/gui/importer/actions/OpenDirectoryLibraryAction.java
@@ -16,15 +16,19 @@
 import org.jabref.gui.util.UiTaskExecutor;
 import org.jabref.logic.ai.AiService;
 import org.jabref.logic.directorylibrary.DirectoryLibraryScanner;
+import org.jabref.logic.directorylibrary.DirectoryLibrarySynchronizer;
 import org.jabref.logic.directorylibrary.PdfEnrichmentTask;
 import org.jabref.logic.directorylibrary.PdfEntryFactory;
 import org.jabref.logic.git.util.GitHandlerRegistry;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.util.BackgroundTask;
+import org.jabref.logic.util.DirectoryMonitor;
 import org.jabref.logic.util.TaskExecutor;
+import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.entry.BibEntryTypesManager;
 import org.jabref.model.util.FileUpdateMonitor;
 
+import com.airhacks.afterburner.injection.Injector;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -121,9 +125,18 @@ private void showLibraryTab(DirectoryLibraryScanner.ScanResult scanResult, PdfEn
                 taskExecutor,
                 gitHandlerRegistry);
         tabContainer.addTab(libraryTab, true);
+        // No change event follows the synchronous tab creation, so set the initial title here
+        libraryTab.updateTabTitle(false);
+
+        BibDatabaseContext databaseContext = scanResult.databaseContext();
+        DirectoryLibrarySynchronizer synchronizer = new DirectoryLibrarySynchronizer(
+                databaseContext, scanResult.catalog(), pdfEntryFactory, UiTaskExecutor::runInJavaFXThread);
+        databaseContext.attachDirectorySynchronizer(synchronizer);
+        synchronizer.startWatching(Injector.instantiateModelOrService(DirectoryMonitor.class));
+
         if (!scanResult.pendingPdfImports().isEmpty()) {
             PdfEnrichmentTask enrichment = new PdfEnrichmentTask(scanResult.pendingPdfImports(), pdfEntryFactory,
-                    scanResult.databaseContext(), UiTaskExecutor::runInJavaFXThread);
+                    databaseContext, UiTaskExecutor::runInJavaFXThread);
             enrichment.onFailure(exception -> LOGGER.error("Extracting PDF metadata failed", exception));
             cancelOnClose(libraryTab, enrichment);
             enrichment.executeWith(taskExecutor);

diff --git a/jablib/src/main/java/module-info.java b/jablib/src/main/java/module-info.java
@@ -244,7 +244,7 @@
     requires transitive com.google.common;
     requires java.string.similarity;
     requires transitive org.apache.commons.csv;
-    requires org.apache.commons.io;
+    requires transitive org.apache.commons.io;
     requires org.apache.commons.lang3;
     requires org.apache.commons.text;
     // endregion

diff --git a/jablib/src/main/java/org/jabref/logic/directorylibrary/DirectoryLibraryCatalog.java b/jablib/src/main/java/org/jabref/logic/directorylibrary/DirectoryLibraryCatalog.java
@@ -40,4 +40,18 @@ public Optional<EntrySource> sourceOf(BibEntry entry) {
     public List<String> entryIdsIn(Path yamlFile) {
         return List.copyOf(entryIdsByFile.getOrDefault(yamlFile, List.of()));
     }
+
+    /// Re-homes all entries of `oldFile` to `newFile` (a rename/move on disk).
+    public void relocateFile(Path oldFile, Path newFile) {
+        Optional.ofNullable(entryIdsByFile.remove(oldFile)).ifPresent(entryIds -> {
+            entryIdsByFile.put(newFile, entryIds);
+            entryIds.forEach(entryId -> sourceByEntryId.computeIfPresent(entryId,
+                    (_, source) -> new EntrySource(newFile, source.hayagrivaKey())));
+        });
+    }
+
+    /// Forgets all entries of the given file (deleted on disk or re-registered afterwards).
+    public void removeFile(Path yamlFile) {
+        Optional.ofNullable(entryIdsByFile.remove(yamlFile)).ifPresent(entryIds -> entryIds.forEach(sourceByEntryId::remove));
+    }
 }