Correctly display discussion posts.

Telegram/SourceFiles/history/history_message.cpp

@@ -553,18 +553,30 @@ int HistoryMessage::viewsCount() const {
 	return HistoryItem::viewsCount();
 }
 
-bool HistoryMessage::displayForwardedAsOriginal() const {
-	if (const auto forwarded = Get<HistoryMessageForwarded>()) {
-		const auto peer = history()->peer;
-		return peer->isSelf() || (peer->isMegagroup() && (peer == from()));
+ChannelData *HistoryMessage::discussionPostOriginalSender() const {
+	if (!history()->peer->isMegagroup()) {
+		return nullptr;
 	}
-	return false;
+	if (const auto forwarded = Get<HistoryMessageForwarded>()) {
+		const auto from = forwarded->savedFromPeer;
+		if (const auto result = from ? from->asChannel() : nullptr) {
+			return result;
+		}
+	}
+	return nullptr;
+}
+
+bool HistoryMessage::isDiscussionPost() const {
+	return (discussionPostOriginalSender() != nullptr);
 }
 
 PeerData *HistoryMessage::displayFrom() const {
-	return displayForwardedAsOriginal()
-		? senderOriginal()
-		: author().get();
+	if (const auto sender = discussionPostOriginalSender()) {
+		return sender;
+	} else if (history()->peer->isSelf()) {
+		return senderOriginal();
+	}
+	return author().get();
 }
 
 bool HistoryMessage::updateDependencyItem() {
@@ -611,8 +623,7 @@ bool HistoryMessage::allowsForward() const {
 }
 
 bool HistoryMessage::hasMessageBadge() const {
-	return hasAdminBadge()
-		|| (displayForwardedAsOriginal() && !history()->peer->isSelf());
+	return hasAdminBadge() || isDiscussionPost();
 }
 
 bool HistoryMessage::isTooOldForEdit(TimeId now) const {

Telegram/SourceFiles/history/history_message.h

@@ -136,7 +136,8 @@ public:
 	[[nodiscard]] MsgId dependencyMsgId() const override {
 		return replyToId();
 	}
-	[[nodiscard]] bool displayForwardedAsOriginal() const;
+	[[nodiscard]] ChannelData *discussionPostOriginalSender() const;
+	[[nodiscard]] bool isDiscussionPost() const;
 
 	// dynamic_cast optimization.
 	[[nodiscard]] HistoryMessage *toHistoryMessage() override {

Telegram/SourceFiles/history/view/history_view_message.cpp

@@ -16,6 +16,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/toast/toast.h"
 #include "data/data_session.h"
 #include "data/data_user.h"
+#include "data/data_channel.h"
 #include "lang/lang_keys.h"
 #include "mainwidget.h"
 #include "mainwindow.h"
@@ -1337,9 +1338,15 @@ bool Message::displayFromName() const {
 
 bool Message::displayForwardedFrom() const {
 	const auto item = message();
-	if (item->displayForwardedAsOriginal()) {
+	if (item->history()->peer->isSelf()) {
 		return false;
-	} else if (const auto forwarded = item->Get<HistoryMessageForwarded>()) {
+	}
+	if (const auto forwarded = item->Get<HistoryMessageForwarded>()) {
+		if (const auto sender = item->discussionPostOriginalSender()) {
+			if (sender == forwarded->originalSender) {
+				return false;
+			}
+		}
 		const auto media = this->media();
 		return item->Has<HistoryMessageVia>()
 			|| !media