Implement workaround for combined emoji (#3469)

CHANGELOG.md

@@ -44,6 +44,7 @@
 - Minor: Mod list, VIP list, and Users joined/parted messages are now searchable. (#3426)
 - Minor: Add search to emote popup. (#3404)
 - Minor: Messages can now be highlighted by subscriber or founder badges. (#3445)
+- Minor: Add workaround for multipart emoji as described in [the RFC](https://mm2pl.github.io/emoji_rfc.pdf). (#3469)
 - Bugfix: Fix Split Input hotkeys not being available when input is hidden (#3362)
 - Bugfix: Fixed colored usernames sometimes not working. (#3170)
 - Bugfix: Restored ability to send duplicate `/me` messages. (#3166)

src/controllers/commands/CommandController.cpp

@@ -66,7 +66,15 @@ void sendWhisperMessage(const QString &text)
     // (hemirt) pajlada: "we should not be sending whispers through jtv, but
     // rather to your own username"
     auto app = getApp();
-    app->twitch.server->sendMessage("jtv", text.simplified());
+    QString toSend = text.simplified();
+
+    // This is to make sure that combined emoji go through properly, see
+    // https://github.com/Chatterino/chatterino2/issues/3384 and
+    // https://mm2pl.github.io/emoji_rfc.pdf for more details
+    // Constants used here are defined in TwitchChannel.hpp
+    toSend.replace(ZERO_WIDTH_JOINER, ESCAPE_TAG);
+
+    app->twitch.server->sendMessage("jtv", toSend);
 }
 
 bool appendWhisperMessageWordsLocally(const QStringList &words)

src/providers/twitch/IrcMessageHandler.cpp

@@ -230,8 +230,15 @@ std::vector<MessagePtr> IrcMessageHandler::parsePrivMessage(
 void IrcMessageHandler::handlePrivMessage(Communi::IrcPrivateMessage *message,
                                           TwitchIrcServer &server)
 {
-    this->addMessage(message, message->target(), message->content(), server,
-                     false, message->isAction());
+    // This is to make sure that combined emoji go through properly, see
+    // https://github.com/Chatterino/chatterino2/issues/3384 and
+    // https://mm2pl.github.io/emoji_rfc.pdf for more details
+    // Constants used here are defined in TwitchChannel.hpp
+
+    this->addMessage(
+        message, message->target(),
+        message->content().replace(COMBINED_FIXER, ZERO_WIDTH_JOINER), server,
+        false, message->isAction());
 }
 
 void IrcMessageHandler::addMessage(Communi::IrcMessage *_message,
@@ -560,8 +567,10 @@ void IrcMessageHandler::handleWhisperMessage(Communi::IrcMessage *message)
 
     auto c = getApp()->twitch.server->whispersChannel.get();
 
-    TwitchMessageBuilder builder(c, message, args, message->parameter(1),
-                                 false);
+    TwitchMessageBuilder builder(
+        c, message, args,
+        message->parameter(1).replace(COMBINED_FIXER, ZERO_WIDTH_JOINER),
+        false);
 
     if (builder.isIgnored())
     {

src/providers/twitch/TwitchChannel.cpp

@@ -106,9 +106,11 @@ namespace {
 
         for (const auto jsonMessage : jsonMessages)
         {
-            auto content = jsonMessage.toString().toUtf8();
+            auto content = jsonMessage.toString();
+            content.replace(COMBINED_FIXER, ZERO_WIDTH_JOINER);
 
-            auto message = Communi::IrcMessage::fromData(content, nullptr);
+            auto message =
+                Communi::IrcMessage::fromData(content.toUtf8(), nullptr);
 
             if (message->command() == "CLEARCHAT")
             {
@@ -365,6 +367,10 @@ void TwitchChannel::sendMessage(const QString &message)
     // Do last message processing
     QString parsedMessage = app->emotes->emojis.replaceShortCodes(message);
 
+    // This is to make sure that combined emoji go through properly, see
+    // https://github.com/Chatterino/chatterino2/issues/3384 and
+    // https://mm2pl.github.io/emoji_rfc.pdf for more details
+    parsedMessage.replace(ZERO_WIDTH_JOINER, ESCAPE_TAG);
     parsedMessage = parsedMessage.simplified();
 
     if (parsedMessage.isEmpty())

src/providers/twitch/TwitchChannel.hpp

@@ -23,6 +23,22 @@
 
 namespace chatterino {
 
+// This is to make sure that combined emoji go through properly, see
+// https://github.com/Chatterino/chatterino2/issues/3384 and
+// https://mm2pl.github.io/emoji_rfc.pdf for more details
+const QString ZERO_WIDTH_JOINER = QString(QChar(0x200D));
+
+// Here be MSVC: Do NOT replace with "\U" literal, it will fail silently.
+namespace {
+    const QChar ESCAPE_TAG_CHARS[2] = {QChar::highSurrogate(0xE0002),
+                                       QChar::lowSurrogate(0xE0002)};
+}
+const QString ESCAPE_TAG = QString(ESCAPE_TAG_CHARS, 2);
+
+const static QRegularExpression COMBINED_FIXER(
+    QString("(?<!%1)%1").arg(ESCAPE_TAG),
+    QRegularExpression::UseUnicodePropertiesOption);
+
 enum class HighlightState;
 
 struct Emote;