Bounds check some tab GetAt()s (#16016)

`GetAt` can throw if the index is out of range. We don't check that in
some places. This fixes some of those.

I don't think this will take care of #15689, but it might help?

(cherry picked from commit 5aaddda)
Service-Card-Id: 90731980
Service-Version: 1.18

Author: zadjii-msft

src/cascadia/TerminalApp/Resources/en-US/Resources.resw

@@ -882,7 +882,11 @@
   </data>
   <data name="TerminalPage_PaneMovedAnnouncement_ExistingWindow" xml:space="preserve">
     <value>Active pane moved to "{0}" tab in "{1}" window</value>
-    <comment>{Locked="{0}"}{Locked="{1}"}This text is read out by screen readers upon a successful pane movement. {0} is the name of the tab the pane was moved to. {1} is the name of the window the pane was moved to.</comment>
+    <comment>{Locked="{0}"}{Locked="{1}"}This text is read out by screen readers upon a successful pane movement. {0} is the name of the tab the pane was moved to. {1} is the name of the window the pane was moved to. Replaced in 1.19 by TerminalPage_PaneMovedAnnouncement_ExistingWindow2</comment>
+  </data>
+  <data name="TerminalPage_PaneMovedAnnouncement_ExistingWindow2" xml:space="preserve">
+    <value>Active pane moved to "{0}" window</value>
+    <comment>{Locked="{0}"}This text is read out by screen readers upon a successful pane movement. {0} is the name of the window the pane was moved to.</comment>
   </data>
   <data name="TerminalPage_PaneMovedAnnouncement_NewWindow" xml:space="preserve">
     <value>Active pane moved to new window</value>

src/cascadia/TerminalApp/TabManagement.cpp

@@ -498,7 +498,7 @@ namespace winrt::TerminalApp::implementation
                 // * B (tabIndex=1): We'll want to focus tab A (now in index 0)
                 // * C (tabIndex=2): We'll want to focus tab B (now in index 1)
                 // * D (tabIndex=3): We'll want to focus tab C (now in index 2)
-                const auto newSelectedIndex = std::clamp<int32_t>(tabIndex - 1, 0, _tabs.Size());
+                const auto newSelectedIndex = std::clamp<int32_t>(tabIndex - 1, 0, _tabs.Size() - 1);
                 // _UpdatedSelectedTab will do the work of setting up the new tab as
                 // the focused one, and unfocusing all the others.
                 auto newSelectedTab{ _tabs.GetAt(newSelectedIndex) };
@@ -665,7 +665,7 @@ namespace winrt::TerminalApp::implementation
     {
         uint32_t tabIndexFromControl{};
         const auto items{ _tabView.TabItems() };
-        if (items.IndexOf(tabViewItem, tabIndexFromControl))
+        if (items.IndexOf(tabViewItem, tabIndexFromControl) && tabIndexFromControl < _tabs.Size())
         {
             // If IndexOf returns true, we've actually got an index
             return _tabs.GetAt(tabIndexFromControl);
@@ -1022,7 +1022,8 @@ namespace winrt::TerminalApp::implementation
     // - suggestedNewTabIndex: the new index of the tab, might get clamped to fit int the tabs row boundaries
     // Return Value:
     // - <none>
-    void TerminalPage::_TryMoveTab(const uint32_t currentTabIndex, const int32_t suggestedNewTabIndex)
+    void TerminalPage::_TryMoveTab(const uint32_t currentTabIndex,
+                                   const int32_t suggestedNewTabIndex)
     {
         auto newTabIndex = gsl::narrow_cast<uint32_t>(std::clamp<int32_t>(suggestedNewTabIndex, 0, _tabs.Size() - 1));
         if (currentTabIndex != newTabIndex)
@@ -1064,16 +1065,21 @@ namespace winrt::TerminalApp::implementation
 
         if (from.has_value() && to.has_value() && to != from)
         {
-            auto& tabs{ _tabs };
-            auto tab = tabs.GetAt(from.value());
-            tabs.RemoveAt(from.value());
-            tabs.InsertAt(to.value(), tab);
-            _UpdateTabIndices();
+            try
+            {
+                auto& tabs{ _tabs };
+                auto tab = tabs.GetAt(from.value());
+                tabs.RemoveAt(from.value());
+                tabs.InsertAt(to.value(), tab);
+                _UpdateTabIndices();
+            }
+            CATCH_LOG();
         }
 
         _rearranging = false;
 
-        if (to.has_value())
+        if (to.has_value() &&
+            *to < gsl::narrow_cast<int32_t>(TabRow().TabView().TabItems().Size()))
         {
             // Selecting the dropped tab
             TabRow().TabView().SelectedIndex(to.value());

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -2026,9 +2026,6 @@ namespace winrt::TerminalApp::implementation
             {
                 if (const auto pane{ terminalTab->GetActivePane() })
                 {
-                    // Get the tab title _before_ moving things around in case the tabIdx doesn't point to the right one after the move
-                    const auto tabTitle = _tabs.GetAt(tabIdx).Title();
-
                     auto startupActions = pane->BuildStartupActions(0, 1, true, true);
                     _DetachPaneFromWindow(pane);
                     _MoveContent(std::move(startupActions.args), windowId, tabIdx);
@@ -2047,7 +2044,7 @@ namespace winrt::TerminalApp::implementation
                         {
                             autoPeer.RaiseNotificationEvent(Automation::Peers::AutomationNotificationKind::ActionCompleted,
                                                             Automation::Peers::AutomationNotificationProcessing::ImportantMostRecent,
-                                                            fmt::format(std::wstring_view{ RS_(L"TerminalPage_PaneMovedAnnouncement_ExistingWindow") }, tabTitle, windowId),
+                                                            fmt::format(std::wstring_view{ RS_(L"TerminalPage_PaneMovedAnnouncement_ExistingWindow2") }, windowId),
                                                             L"TerminalPageMovePaneToExistingWindow" /* unique name for this notification category */);
                         }
                     }
@@ -2064,7 +2061,7 @@ namespace winrt::TerminalApp::implementation
 
         // Moving the pane from the current tab might close it, so get the next
         // tab before its index changes.
-        if (_tabs.Size() > tabIdx)
+        if (tabIdx < _tabs.Size())
         {
             auto targetTab = _GetTerminalTabImpl(_tabs.GetAt(tabIdx));
             // if the selected tab is not a host of terminals (e.g. settings)