do tag rename and tag clearing in background; move logic to tags.py

Because the logic is in rename_tag() now, it means we create a
checkpoint even if the tag is orphaned. This is because currently
checkpointing is a GUI responsibility. In the future we need to introduce
multi-level undo, and should move responsibility for managing it
to the backend.

pylib/anki/tags.py

@@ -13,7 +13,7 @@ from __future__ import annotations
 
 import pprint
 import re
-from typing import Collection, List, Optional, Tuple
+from typing import Collection, List, Optional, Sequence, Tuple
 
 import anki  # pylint: disable=unused-import
 from anki.utils import ids2str
@@ -92,7 +92,7 @@ class TagManager:
         return self.col.backend.add_note_tags(nids=nids, tags=tags)
 
     def bulk_update(
-        self, nids: List[int], tags: str, replacement: str, regex: bool
+        self, nids: Sequence[int], tags: str, replacement: str, regex: bool
     ) -> int:
         """Replace space-separated tags, returning changed count.
         Tags replaced with an empty string will be removed."""
@@ -100,6 +100,15 @@ class TagManager:
             nids=nids, tags=tags, replacement=replacement, regex=regex
         )
 
+    def rename_tag(self, old: str, new: str) -> int:
+        "Rename provided tag, returning number of changed notes."
+        escaped_name = re.sub(r"[*_\\]", r"\\\g<0>", old)
+        escaped_name = '"{}"'.format(escaped_name.replace('"', '\\"'))
+        nids = self.col.find_notes("tag:" + escaped_name)
+        if not nids:
+            return 0
+        return self.col.tags.bulk_update(nids, old, new, False)
+
     # legacy routines
 
     def bulkAdd(self, ids: List[int], tags: str, add: bool = True) -> None:

qt/aqt/browser.py

@@ -6,6 +6,7 @@ from __future__ import annotations
 import html
 import re
 import time
+from concurrent.futures import Future
 from dataclasses import dataclass
 from enum import Enum
 from operator import itemgetter
@@ -1649,8 +1650,11 @@ where id in %s"""
         self.editor.saveNow(self._clearUnusedTags)
 
     def _clearUnusedTags(self):
-        self.col.tags.registerNotes()
-        self.on_tag_list_update()
+        def on_done(fut: Future):
+            fut.result()
+            self.on_tag_list_update()
+
+        self.mw.taskman.run_in_background(self.col.tags.registerNotes, on_done)
 
     # Suspending
     ######################################################################

qt/aqt/sidebar.py

@@ -4,6 +4,7 @@
 from __future__ import annotations
 
 import re
+from concurrent.futures import Future
 from enum import Enum
 
 import aqt
@@ -92,7 +93,7 @@ class NewSidebarTreeView(SidebarTreeViewBase):
             a.triggered.connect(lambda _, func=act_func: func(item))  # type: ignore
         m.exec_(QCursor.pos())
 
-    def rename_deck(self, item: aqt.browser.SidebarItem) -> None:
+    def rename_deck(self, item: "aqt.browser.SidebarItem") -> None:
         deck = self.mw.col.decks.get(item.id)
         old_name = deck["name"]
         new_name = getOnlyText(tr(TR.DECKS_NEW_DECK_NAME), default=old_name)
@@ -107,24 +108,29 @@ class NewSidebarTreeView(SidebarTreeViewBase):
         self.browser.maybeRefreshSidebar()
         self.mw.deckBrowser.refresh()
 
-    def rename_tag(self, item: aqt.browser.SidebarItem) -> None:
+    def rename_tag(self, item: "aqt.browser.SidebarItem") -> None:
         self.browser.editor.saveNow(lambda: self._rename_tag(item))
 
-    def _rename_tag(self, item: aqt.browser.SidebarItem) -> None:
+    def _rename_tag(self, item: "aqt.browser.SidebarItem") -> None:
         old_name = item.name
-        escaped_name = re.sub(r"[*_\\]", r"\\\g<0>", old_name)
-        escaped_name = '"{}"'.format(escaped_name.replace('"', '\\"'))
-        nids = self.col.find_notes("tag:" + escaped_name)
-        if len(nids) == 0:
-            showInfo(tr(TR.BROWSING_TAG_RENAME_WARNING_EMPTY))
-            return
         new_name = getOnlyText(tr(TR.ACTIONS_NEW_NAME), default=old_name)
         if new_name == old_name or not new_name:
             return
+
+        def do_rename():
+            return self.col.tags.rename_tag(old_name, new_name)
+
+        def on_done(fut: Future):
+            self.mw.requireReset(reason=ResetReason.BrowserAddTags, context=self)
+            self.browser.model.endReset()
+
+            count = fut.result()
+            if not count:
+                showInfo(tr(TR.BROWSING_TAG_RENAME_WARNING_EMPTY))
+                return
+
+            self.browser.clearUnusedTags()
+
         self.mw.checkpoint(tr(TR.ACTIONS_RENAME_TAG))
         self.browser.model.beginReset()
-        self.col.tags.bulk_update(list(nids), old_name, new_name, False)
-        self.browser.model.endReset()
-        self.browser.clearUnusedTags()
-        self.mw.requireReset(reason=ResetReason.BrowserAddTags, context=self)
-        self.browser.maybeRefreshSidebar()
+        self.mw.taskman.run_in_background(do_rename, on_done)