Make opening threads from a usercard opened with /usercard not crash the client (#3905)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## Unversioned
 
-- Major: Added support for Twitch's Chat Replies. [Wiki Page](https://wiki.chatterino.com/Features/#message-replies) (#3722, #3989, #4041, #4047, #4055, #4067, #4077)
+- Major: Added support for Twitch's Chat Replies. [Wiki Page](https://wiki.chatterino.com/Features/#message-replies) (#3722, #3989, #4041, #4047, #4055, #4067, #4077, #3905)
 - Major: Added multi-channel searching to search dialog via keyboard shortcut. (Ctrl+Shift+F by default) (#3694, #3875)
 - Major: Added support for emotes and badges from [7TV](https://7tv.app). [Wiki Page](https://wiki.chatterino.com/Third_party_services/#7tv) (#4002, #4062)
 - Minor: Added highlights for `Elevated Messages`. (#4016)

src/controllers/commands/CommandController.cpp

@@ -32,6 +32,7 @@
 #include "widgets/dialogs/ReplyThreadPopup.hpp"
 #include "widgets/dialogs/UserInfoPopup.hpp"
 #include "widgets/splits/Split.hpp"
+#include "widgets/splits/SplitContainer.hpp"
 
 #include <QApplication>
 #include <QDesktopServices>
@@ -838,10 +839,49 @@ void CommandController::initialize(Settings &, Paths &paths)
             channel = channelTemp;
         }
 
+        // try to link to current split if possible
+        Split *currentSplit = nullptr;
+        auto *currentPage = dynamic_cast<SplitContainer *>(
+            getApp()->windows->getMainWindow().getNotebook().getSelectedPage());
+        if (currentPage != nullptr)
+        {
+            currentSplit = currentPage->getSelectedSplit();
+        }
+
+        auto differentChannel =
+            currentSplit != nullptr && currentSplit->getChannel() != channel;
+        if (differentChannel || currentSplit == nullptr)
+        {
+            // not possible to use current split, try searching for one
+            const auto &notebook =
+                getApp()->windows->getMainWindow().getNotebook();
+            auto count = notebook.getPageCount();
+            for (int i = 0; i < count; i++)
+            {
+                auto *page = notebook.getPageAt(i);
+                auto *container = dynamic_cast<SplitContainer *>(page);
+                assert(container != nullptr);
+                for (auto *split : container->getSplits())
+                {
+                    if (split->getChannel() == channel)
+                    {
+                        currentSplit = split;
+                        break;
+                    }
+                }
+            }
+
+            // This would have crashed either way.
+            assert(currentSplit != nullptr &&
+                   "something went HORRIBLY wrong with the /usercard "
+                   "command. It couldn't find a split for a channel which "
+                   "should be open.");
+        }
+
         auto *userPopup = new UserInfoPopup(
             getSettings()->autoCloseUserPopup,
             static_cast<QWidget *>(&(getApp()->windows->getMainWindow())),
-            nullptr);
+            currentSplit);
         userPopup->setData(userName, channel);
         userPopup->move(QCursor::pos());
         userPopup->show();

src/widgets/dialogs/UserInfoPopup.cpp

@@ -135,6 +135,8 @@ UserInfoPopup::UserInfoPopup(bool closeAutomatically, QWidget *parent,
     : DraggablePopup(closeAutomatically, parent)
     , split_(split)
 {
+    assert(split != nullptr &&
+           "split being nullptr causes lots of bugs down the road");
     this->setWindowTitle("Usercard");
     this->setStayInScreenRect(true);