user [nfc]: Factor out an allUsers iterable

Author: gnprice

lib/model/autocomplete.dart

@@ -449,7 +449,7 @@ class MentionAutocompleteView extends AutocompleteView<MentionAutocompleteQuery,
     required PerAccountStore store,
     required Narrow narrow,
   }) {
-    return store.users.values.toList()
+    return store.allUsers.toList()
       ..sort(_comparator(store: store, narrow: narrow));
   }
 

lib/model/compose.dart

@@ -132,7 +132,7 @@ String wrapWithBacktickFence({required String content, String? infoString}) {
 /// through all users; avoid it in performance-sensitive codepaths.
 String userMention(User user, {bool silent = false, UserStore? users}) {
   bool includeUserId = users == null
-    || users.users.values.where((u) => u.fullName == user.fullName)
+    || users.allUsers.where((u) => u.fullName == user.fullName)
          .take(2).length == 2;
 
   return '@${silent ? '_' : ''}**${user.fullName}${includeUserId ? '|${user.userId}' : ''}**';

lib/model/user.dart

@@ -46,6 +46,15 @@ mixin UserStore {
   /// For details, see [users].
   User? getUser(int userId) => users[userId];
 
+  /// All known users in the realm.
+  ///
+  /// This may have a large number of elements, like tens of thousands.
+  /// Consider [getUser] or other alternatives to iterating through this.
+  ///
+  /// There may be perfectly real users which are not known
+  /// and so are not found here.  For details, see [users].
+  Iterable<User> get allUsers => users.values;
+
   /// The name to show the given user as in the UI, even for unknown users.
   ///
   /// This is the user's [User.fullName] if the user is known,

test/model/store_test.dart

@@ -411,7 +411,7 @@ void main() {
       //    clobber the recorded registerQueue request so we can't check it.
       // checkLastRequest();
 
-      check(updateMachine.store.users.values).unorderedMatches(
+      check(updateMachine.store.allUsers).unorderedMatches(
         users.map((expected) => (it) => it.fullName.equals(expected.fullName)));
     }));
 
@@ -468,7 +468,7 @@ void main() {
       updateMachine.debugPauseLoop();
       check(complete).isTrue();
       // checkLastRequest(); TODO UpdateMachine.debugPauseLoop was too late; see comment above
-      check(updateMachine.store.users.values).unorderedMatches(
+      check(updateMachine.store.allUsers).unorderedMatches(
         users.map((expected) => (it) => it.fullName.equals(expected.fullName)));
     }));