fix: address review — conditional group re-fetch, participant de-dupe, nits

Author: blue-archon

lib/database/global/message_summary_info.dart

@@ -27,7 +27,7 @@ class MessageSummaryInfo {
                   )
                 }
               : Map<String, List<EditedContent>>.from(
-                  asStringDynamicMapRequired(json["editedContent"])!.map(
+                  asStringDynamicMapRequired(json["editedContent"]).map(
                     (k, v) => MapEntry(
                       k,
                       List<EditedContent>.from(
@@ -41,7 +41,7 @@ class MessageSummaryInfo {
           : json["originalTextRange"] is List
               ? {"0": List<int>.from(json["originalTextRange"])}
               : Map<String, List<int>>.from(
-                  asStringDynamicMapRequired(json["originalTextRange"])!.map(
+                  asStringDynamicMapRequired(json["originalTextRange"]).map(
                     (k, v) => MapEntry(k.toString(), List<int>.from(v as List)),
                   ),
                 ),

lib/services/backend/actions/chat_actions.dart

@@ -306,12 +306,17 @@ class ChatActions {
           // the message is linked to the contact-aware handle instead of creating
           // an orphaned duplicate.
           final addr = inputMessage.handle!.address;
-          final altAddr = addr.startsWith('+') ? addr.substring(1) : '+$addr';
-          final altUAS = '$altAddr/${inputMessage.handle!.service}';
-          final altQuery = handleBox.query(Handle_.uniqueAddressAndService.equals(altUAS)).build();
-          altQuery.limit = 1;
-          final altHandle = altQuery.findFirst();
-          altQuery.close();
+          // Only phone numbers have a +/− prefix variant. Skip emails — an '@'
+          // address would otherwise produce a nonsensical "+user@example.com" query.
+          Handle? altHandle;
+          if (!addr.contains('@')) {
+            final altAddr = addr.startsWith('+') ? addr.substring(1) : '+$addr';
+            final altUAS = '$altAddr/${inputMessage.handle!.service}';
+            final altQuery = handleBox.query(Handle_.uniqueAddressAndService.equals(altUAS)).build();
+            altQuery.limit = 1;
+            altHandle = altQuery.findFirst();
+            altQuery.close();
+          }
 
           if (altHandle != null) {
             handleToLink = altHandle;
@@ -403,12 +408,30 @@ class ChatActions {
             needsUpdate = true;
           }
 
-          // Keep chat participant list in sync when we resolve a new sender
-          if (handleToLink != null &&
-              dbChat != null &&
-              !dbChat.handles.any((h) => h.originalROWID == handleToLink!.originalROWID)) {
-            dbChat.handles.add(handleToLink);
-            dbChat.handles.applyToDb();
+          // Keep the chat's participant list in sync with the resolved sender and
+          // collapse any duplicate entries. De-dupe on the handle's real identity
+          // (address + service, its unique key) as well as originalROWID: a
+          // message's sender handle can carry a null/mismatched originalROWID
+          // versus the copy already linked to the chat, and an originalROWID-only
+          // guard both re-adds the same number and never removes a pre-existing
+          // duplicate (ToMany is a list, so the same handle can appear twice).
+          if (handleToLink != null && dbChat != null) {
+            bool sameIdentity(Handle a, Handle b) =>
+                (a.originalROWID != null && a.originalROWID == b.originalROWID) ||
+                (a.address == b.address && a.service == b.service);
+            final current = List<Handle>.from(dbChat.handles);
+            final deduped = <Handle>[];
+            for (final h in current) {
+              if (!deduped.any((d) => sameIdentity(d, h))) deduped.add(h);
+            }
+            final hadDuplicate = deduped.length != current.length;
+            final senderMissing = !deduped.any((d) => sameIdentity(d, handleToLink!));
+            if (senderMissing) deduped.add(handleToLink);
+            if (hadDuplicate || senderMissing) {
+              dbChat.handles.clear();
+              dbChat.handles.addAll(deduped);
+              dbChat.handles.applyToDb();
+            }
           }
 
           // Process and link attachments if present

lib/services/backend/incoming_message_handler.dart

@@ -536,9 +536,16 @@ class IncomingMessageHandler {
       final chatForCheck = local ?? partial;
       final incomingFromOther = !(m.isFromMe ?? false);
 
-      // Always refresh participants for incoming group messages — push payloads
-      // carry handleId only, and a stale local participant list breaks linking.
+      // For incoming group messages, only re-fetch participants when the sender's
+      // handle isn't already resolvable locally. Push payloads carry handleId only,
+      // so a missing sender is what breaks linking; when we already have it, skip
+      // the server round-trip (re-fetching on every group message doesn't scale).
       if (incomingFromOther && _chatIsGroup(chatForCheck)) {
+        final senderResolvable =
+            m.handleId != null && (local?.handles.any((h) => h.originalROWID == m.handleId) ?? false);
+        if (senderResolvable) {
+          return (chat: local!, affectedHandleIds: <int>[]);
+        }
         Logger.debug(
           'Refetching group participants for ${partial.guid} (handleId=${m.handleId})',
           tag: _tag,