msglist [nfc]: s/composeBox{Controller,State}/ in MessageListPageState

Soon we'll want a method for starting a message-edit session, and
it'll make sense to put it on ComposeBoxState rather than
ComposeBoxController; one reason is that it'll need UI code to show
an error dialog.

With this change, the ComposeBoxState -- and so that new method --
will be accessible in the message-list widget code, where we open
the message action sheet from.

Author: chrisbobbe

lib/widgets/action_sheet.dart

@@ -562,7 +562,7 @@ void showMessageActionSheet({required BuildContext context, required Message mes
   // So we rely on the fact that isComposeBoxOffered for any given message list
   // will be constant through the page's life.
   final messageListPage = MessageListPage.ancestorOf(pageContext);
-  final isComposeBoxOffered = messageListPage.composeBoxController != null;
+  final isComposeBoxOffered = messageListPage.composeBoxState != null;
 
   final isMessageRead = message.flags.contains(MessageFlag.read);
   final markAsUnreadSupported = store.zulipFeatureLevel >= 155; // TODO(server-6)
@@ -827,7 +827,7 @@ class QuoteAndReplyButton extends MessageActionSheetMenuItemButton {
     final zulipLocalizations = ZulipLocalizations.of(pageContext);
     final message = this.message;
 
-    var composeBoxController = findMessageListPage().composeBoxController;
+    var composeBoxController = findMessageListPage().composeBoxState?.controller;
     // The compose box doesn't null out its controller; it's either always null
     // (e.g. in Combined Feed) or always non-null; it can't have been nulled out
     // after the action sheet opened.
@@ -857,7 +857,7 @@ class QuoteAndReplyButton extends MessageActionSheetMenuItemButton {
 
     if (!pageContext.mounted) return;
 
-    composeBoxController = findMessageListPage().composeBoxController;
+    composeBoxController = findMessageListPage().composeBoxState?.controller;
     // The compose box doesn't null out its controller; it's either always null
     // (e.g. in Combined Feed) or always non-null; it can't have been nulled out
     // during the raw-content request.

lib/widgets/message_list.dart

@@ -149,10 +149,10 @@ abstract class MessageListPageState {
   /// The narrow for this page's message list.
   Narrow get narrow;
 
-  /// The controller for this [MessageListPage]'s compose box,
+  /// The [ComposeBoxState] for this [MessageListPage]'s compose box,
   /// if this [MessageListPage] offers a compose box and it has mounted,
   /// else null.
-  ComposeBoxController? get composeBoxController;
+  ComposeBoxState? get composeBoxState;
 
   /// The active [MessageListView].
   ///
@@ -192,7 +192,7 @@ class _MessageListPageState extends State<MessageListPage> implements MessageLis
   late Narrow narrow;
 
   @override
-  ComposeBoxController? get composeBoxController => _composeBoxKey.currentState?.controller;
+  ComposeBoxState? get composeBoxState => _composeBoxKey.currentState;
   final GlobalKey<ComposeBoxState> _composeBoxKey = GlobalKey();
 
   @override

test/widgets/message_list_test.dart

@@ -136,20 +136,20 @@ void main() {
       check(state.narrow).equals(ChannelNarrow(stream.streamId));
     });
 
-    testWidgets('composeBoxController finds compose box', (tester) async {
+    testWidgets('composeBoxState finds compose box', (tester) async {
       final stream = eg.stream();
       await setupMessageListPage(tester, narrow: ChannelNarrow(stream.streamId),
         streams: [stream],
         messages: [eg.streamMessage(stream: stream, content: "<p>a message</p>")]);
       final state = MessageListPage.ancestorOf(tester.element(find.text("a message")));
-      check(state.composeBoxController).isNotNull();
+      check(state.composeBoxState).isNotNull();
     });
 
-    testWidgets('composeBoxController null when no compose box', (tester) async {
+    testWidgets('composeBoxState null when no compose box', (tester) async {
       await setupMessageListPage(tester, narrow: const CombinedFeedNarrow(),
         messages: [eg.streamMessage(content: "<p>a message</p>")]);
       final state = MessageListPage.ancestorOf(tester.element(find.text("a message")));
-      check(state.composeBoxController).isNull();
+      check(state.composeBoxState).isNull();
     });
 
     testWidgets('dispose MessageListView when event queue expired', (tester) async {
@@ -256,7 +256,7 @@ void main() {
       // Verify this message list lacks a compose box.
       // (The original bug wouldn't reproduce with a compose box present.)
       final state = MessageListPage.ancestorOf(tester.element(find.text("verb\natim")));
-      check(state.composeBoxController).isNull();
+      check(state.composeBoxState).isNull();
 
       final element = tester.element(find.byType(CodeBlock));
       final padding = MediaQuery.of(element).padding;