Fix #7888 ({tags} control generate 'tags' word for empty tags collection). Don't refresh the Tag browser if it is hidden. SHould speed up metadata editing with large libraries, if you hide teh Tag Browser.

src/calibre/gui2/dialogs/tag_categories.py

@@ -145,7 +145,7 @@ class TagCategories(QDialog, Ui_TagCategories):
             index = self.all_items[node.data(Qt.UserRole).toPyObject()].index
             if index not in self.applied_items:
                 self.applied_items.append(index)
-        self.applied_items.sort(key=lambda x:sort_key(self.all_items[x]))
+        self.applied_items.sort(key=lambda x:sort_key(self.all_items[x].name))
         self.display_filtered_categories(None)
 
     def unapply_tags(self, node=None):

src/calibre/gui2/init.py

@@ -123,6 +123,8 @@ class Stack(QStackedWidget): # {{{
                 _('Tag Browser'), I('tags.png'),
                 parent=parent, side_index=0, initial_side_size=200,
                 shortcut=_('Shift+Alt+T'))
+        parent.tb_splitter.state_changed.connect(
+                        self.tb_widget.set_pane_is_visible, Qt.QueuedConnection)
         parent.tb_splitter.addWidget(self.tb_widget)
         parent.tb_splitter.addWidget(parent.cb_splitter)
         parent.tb_splitter.setCollapsible(parent.tb_splitter.other_index, False)

src/calibre/gui2/tag_view.py

@@ -87,6 +87,13 @@ class TagsView(QTreeView): # {{{
         self.setDragDropMode(self.DropOnly)
         self.setDropIndicatorShown(True)
         self.setAutoExpandDelay(500)
+        self.pane_is_visible = False
+
+    def set_pane_is_visible(self, to_what):
+        pv = self.pane_is_visible
+        self.pane_is_visible = to_what
+        if to_what and not pv:
+            self.recount()
 
     def set_database(self, db, tag_match, sort_by):
         self.hidden_categories = config['tag_browser_hidden_categories']
@@ -300,7 +307,7 @@ class TagsView(QTreeView): # {{{
         return self.isExpanded(idx)
 
     def recount(self, *args):
-        if self.disable_recounting:
+        if self.disable_recounting or not self.pane_is_visible:
             return
         self.refresh_signal_processed = True
         ci = self.currentIndex()
@@ -969,6 +976,7 @@ class TagBrowserWidget(QWidget): # {{{
         self._layout.setContentsMargins(0,0,0,0)
 
         parent.tags_view = TagsView(parent)
+        self.tags_view = parent.tags_view
         self._layout.addWidget(parent.tags_view)
 
         parent.sort_by = QComboBox(parent)
@@ -998,6 +1006,9 @@ class TagBrowserWidget(QWidget): # {{{
                 _('Add your own categories to the Tag Browser'))
         parent.edit_categories.setStatusTip(parent.edit_categories.toolTip())
 
+    def set_pane_is_visible(self, to_what):
+        self.tags_view.set_pane_is_visible(to_what)
+
 
 # }}}
 

src/calibre/library/save_to_disk.py

@@ -119,10 +119,8 @@ class SafeFormat(TemplateFormatter):
             try:
                 b = self.book.get_user_metadata(key, False)
             except:
-                if DEBUG:
                 traceback.print_exc()
                 b = None
-
             if b is not None and b['datatype'] == 'composite':
                 if key in self.composite_values:
                     return self.composite_values[key]
@@ -135,7 +133,6 @@ class SafeFormat(TemplateFormatter):
                 return val.replace('/', '_').replace('\\', '_')
             return ''
         except:
-            if DEBUG:
             traceback.print_exc()
             return key
 
@@ -155,6 +152,8 @@ def get_components(template, mi, id, timefmt='%b %Y', length=250,
         format_args['tags'] = mi.format_tags()
         if format_args['tags'].startswith('/'):
             format_args['tags'] = format_args['tags'][1:]
+    else:
+        format_args['tags'] = ''
     if mi.series:
         format_args['series'] = tsfmt(mi.series)
         if mi.series_index is not None: