Fix AnkiWebPage not being initialized for default web view kinds (e.g. in add-ons) (#3933)

* add AnkiWebView subclasses for stats, empty cards and find dupes ui

* update ui files to use subclassed webviews instead

* remove superfluous calls to AnkiWebView.set_kind

* Avoid set_kind() race condition in legacy stats webview

Replacing the web view is a hacky workaround, but likely a reasonable compromise for a legacy view that we do not want to maintain a separate Qt form for.

* Slightly refactor AnkiWebView subclass creation and tweak inline comment

+ Extend create_ankiwebview_subclass() with the ability to set any
  init time AnkiWebView argument
+ Introduce some nice-to-haves in terms of static type checking support
  and IDE autocompletion
+ Mark helper function as private to discourage add-on use

* Drop `AnkiWebView.set_kind` completely

There no longer is an Anki-internal use case for changing the web view kind after initializing a web view, and add-ons almost certainly do not have any use for it either.

Given that setting the kind after web view construction can lead  to known race conditions with `domDone` signals, we should remove this method to discourage uses like this in both Anki code and add-on consumers.

There currenty only seems to be one add-on calling `set_kind()`, so this seem like a justifiable API change.

---------

Co-authored-by: llama <100429699+iamllama@users.noreply.github.com>

qt/aqt/browser/find_duplicates.py

@@ -14,7 +14,6 @@ from anki.collection import SearchNode
 from anki.notes import NoteId
 from aqt.qt import *
 from aqt.qt import sip
-from aqt.webview import AnkiWebViewKind
 
 from ..operations import QueryOp
 from ..operations.tag import add_tags_to_notes
@@ -52,7 +51,6 @@ class FindDuplicatesDialog(QDialog):
         self._dupes: list[tuple[str, list[NoteId]]] = []
 
         # links
-        form.webView.set_kind(AnkiWebViewKind.FIND_DUPLICATES)
         form.webView.set_bridge_command(self._on_duplicate_clicked, context=self)
         form.webView.stdHtml("", context=self)
 

qt/aqt/emptycards.py

@@ -15,7 +15,6 @@ from anki.collection import EmptyCardsReport
 from aqt import gui_hooks
 from aqt.qt import QDialog, QDialogButtonBox, qconnect
 from aqt.utils import disable_help_button, restoreGeom, saveGeom, tooltip, tr
-from aqt.webview import AnkiWebViewKind
 
 
 def show_empty_cards(mw: aqt.main.AnkiQt) -> None:
@@ -47,7 +46,6 @@ class EmptyCardsDialog(QDialog):
         self.setWindowTitle(tr.empty_cards_window_title())
         disable_help_button(self)
         self.form.keep_notes.setText(tr.empty_cards_preserve_notes_checkbox())
-        self.form.webview.set_kind(AnkiWebViewKind.EMPTY_CARDS)
         self.form.webview.set_bridge_command(self._on_note_link_clicked, self)
 
         gui_hooks.empty_cards_will_show(self)

qt/aqt/forms/emptycards.ui

@@ -30,7 +30,7 @@
     <number>0</number>
    </property>
    <item>
-    <widget class="AnkiWebView" name="webview" native="true">
+    <widget class="EmptyCardsWebView" name="webview" native="true">
      <property name="url" stdset="0">
       <url>
        <string notr="true">about:blank</string>
@@ -81,7 +81,7 @@
  </widget>
  <customwidgets>
   <customwidget>
-   <class>AnkiWebView</class>
+   <class>EmptyCardsWebView</class>
    <extends>QWidget</extends>
    <header location="global">aqt/webview</header>
    <container>1</container>

qt/aqt/forms/finddupes.ui

@@ -73,7 +73,7 @@
        <number>0</number>
       </property>
       <item>
-       <widget class="AnkiWebView" name="webView" native="true">
+       <widget class="FindDupesWebView" name="webView" native="true">
         <property name="url" stdset="0">
          <url>
           <string notr="true">about:blank</string>
@@ -98,7 +98,7 @@
  </widget>
  <customwidgets>
   <customwidget>
-   <class>AnkiWebView</class>
+   <class>FindDupesWebView</class>
    <extends>QWidget</extends>
    <header location="global">aqt/webview</header>
    <container>1</container>

qt/aqt/forms/stats.ui

@@ -30,7 +30,7 @@
     <number>0</number>
    </property>
    <item>
-    <widget class="AnkiWebView" name="web" native="true">
+    <widget class="StatsWebView" name="web" native="true">
      <property name="url" stdset="0">
       <url>
        <string notr="true">about:blank</string>
@@ -146,7 +146,7 @@
  </widget>
  <customwidgets>
   <customwidget>
-   <class>AnkiWebView</class>
+   <class>StatsWebView</class>
    <extends>QWidget</extends>
    <header location="global">aqt/webview</header>
    <container>1</container>

qt/aqt/stats.py

@@ -25,7 +25,7 @@ from aqt.utils import (
     tooltip,
     tr,
 )
-from aqt.webview import AnkiWebViewKind
+from aqt.webview import LegacyStatsWebView
 
 
 class NewDeckStats(QDialog):
@@ -71,7 +71,6 @@ class NewDeckStats(QDialog):
         maybeHideClose(self.form.buttonBox)
         addCloseShortcut(self)
         gui_hooks.stats_dialog_will_show(self)
-        self.form.web.set_kind(AnkiWebViewKind.DECK_STATS)
         self.form.web.hide_while_preserving_layout()
         self.show()
         self.refresh()
@@ -154,6 +153,9 @@ class DeckStats(QDialog):
         self.name = "deckStats"
         self.period = 0
         self.form = aqt.forms.stats.Ui_Dialog()
+        # Hack: Switch out web views dynamically to avoid maintaining multiple
+        # Qt forms for different versions of the stats dialog.
+        self.form.web = LegacyStatsWebView(self.mw)
         self.oldPos = None
         self.wholeCollection = False
         self.setMinimumWidth(700)
@@ -232,7 +234,6 @@ class DeckStats(QDialog):
         stats = self.mw.col.stats()
         stats.wholeCollection = self.wholeCollection
         self.report = stats.report(type=self.period)
-        self.form.web.set_kind(AnkiWebViewKind.LEGACY_DECK_STATS)
         self.form.web.stdHtml(
             f"<html><body>{self.report}</body></html>",
             js=["js/vendor/jquery.min.js", "js/vendor/plot.js"],

qt/aqt/webview.py

@@ -10,7 +10,9 @@ import re
 import sys
 from collections.abc import Callable, Sequence
 from enum import Enum
-from typing import TYPE_CHECKING, Any, cast
+from typing import TYPE_CHECKING, Any, Type, cast
+
+from typing_extensions import TypedDict, Unpack
 
 import anki
 import anki.lang
@@ -360,7 +362,9 @@ class AnkiWebView(QWebEngineView):
         kind: AnkiWebViewKind = AnkiWebViewKind.DEFAULT,
     ) -> None:
         QWebEngineView.__init__(self, parent=parent)
-        self.set_kind(kind)
+        self._kind = kind
+        self.set_title(kind.value)
+        self.setPage(AnkiWebPage(self._onBridgeCmd, kind, self))
         # reduce flicker
         self.page().setBackgroundColor(theme_manager.qcolor(colors.CANVAS))
 
@@ -390,17 +394,6 @@ class AnkiWebView(QWebEngineView):
         """
         )
 
-    def set_kind(self, kind: AnkiWebViewKind) -> None:
-        self._kind = kind
-        self.set_title(kind.value)
-        # this is an ugly hack to avoid breakages caused by
-        # creating a default webview then immediately calling set_kind, which results
-        # in the creation of two pages, and the second fails as the domDone
-        # signal from the first one is received
-        if kind != AnkiWebViewKind.DEFAULT:
-            self.setPage(AnkiWebPage(self._onBridgeCmd, kind, self))
-            self.page().setBackgroundColor(theme_manager.qcolor(colors.CANVAS))
-
     def page(self) -> AnkiWebPage:
         return cast(AnkiWebPage, super().page())
 
@@ -968,3 +961,53 @@ html {{ {font} }}
     @deprecated(info="use theme_manager.qcolor() instead")
     def get_window_bg_color(self, night_mode: bool | None = None) -> QColor:
         return theme_manager.qcolor(colors.CANVAS)
+
+
+# Pre-configured classes for use in Qt Designer
+##########################################################################
+
+
+class _AnkiWebViewKwargs(TypedDict, total=False):
+    parent: QWidget | None
+    title: str
+    kind: AnkiWebViewKind
+
+
+def _create_ankiwebview_subclass(
+    name: str,
+    /,
+    **fixed_kwargs: Unpack[_AnkiWebViewKwargs],
+) -> Type[AnkiWebView]:
+
+    def __init__(self, *args: Any, **kwargs: _AnkiWebViewKwargs) -> None:
+        # user‑supplied kwargs override fixed kwargs
+        merged = cast(_AnkiWebViewKwargs, {**fixed_kwargs, **kwargs})
+        AnkiWebView.__init__(self, *args, **merged)
+
+    __init__.__qualname__ = f"{name}.__init__"
+    if fixed_kwargs:
+        __init__.__doc__ = (
+            f"Auto‑generated wrapper that pre‑sets "
+            f"{', '.join(f'{k}={v!r}' for k, v in fixed_kwargs.items())}."
+        )
+
+    cls: Type[AnkiWebView] = type(name, (AnkiWebView,), {"__init__": __init__})
+
+    return cls
+
+
+# These subclasses are used in Qt Designer UI files to allow for configuring
+# web views at initialization time (custom widgets can otherwise only be
+# initialized with the default constructor)
+StatsWebView = _create_ankiwebview_subclass(
+    "StatsWebView", kind=AnkiWebViewKind.DECK_STATS
+)
+LegacyStatsWebView = _create_ankiwebview_subclass(
+    "LegacyStatsWebView", kind=AnkiWebViewKind.LEGACY_DECK_STATS
+)
+EmptyCardsWebView = _create_ankiwebview_subclass(
+    "EmptyCardsWebView", kind=AnkiWebViewKind.EMPTY_CARDS
+)
+FindDupesWebView = _create_ankiwebview_subclass(
+    "FindDupesWebView", kind=AnkiWebViewKind.FIND_DUPLICATES
+)