Prevent the horizontal tab character wrapping at the end of a line

src/host/_stream.cpp

@@ -744,7 +744,6 @@ using Microsoft::Console::VirtualTerminal::StateMachine;
             if (screenInfo.InVTMode())
             {
                 const COORD cCursorOld = cursor.GetPosition();
-                // Get Forward tab handles tabbing past the end of the buffer
                 CursorPosition = screenInfo.GetForwardTab(cCursorOld);
             }
             else

src/host/getset.cpp

@@ -1567,19 +1567,15 @@ void DoSrvPrivateUseMainScreenBuffer(SCREEN_INFORMATION& screenInfo)
 {
     CONSOLE_INFORMATION& gci = ServiceLocator::LocateGlobals().getConsoleInformation();
     SCREEN_INFORMATION& _screenBuffer = gci.GetActiveOutputBuffer().GetActiveBuffer();
+    COORD cursorPos = _screenBuffer.GetTextBuffer().GetCursor().GetPosition();
 
-    NTSTATUS Status = STATUS_SUCCESS;
     FAIL_FAST_IF(!(sNumTabs >= 0));
-    for (SHORT sTabsExecuted = 0; sTabsExecuted < sNumTabs && NT_SUCCESS(Status); sTabsExecuted++)
+    for (SHORT sTabsExecuted = 0; sTabsExecuted < sNumTabs; sTabsExecuted++)
     {
-        const COORD cursorPos = _screenBuffer.GetTextBuffer().GetCursor().GetPosition();
-        COORD cNewPos = (fForward) ? _screenBuffer.GetForwardTab(cursorPos) : _screenBuffer.GetReverseTab(cursorPos);
-        // GetForwardTab is smart enough to move the cursor to the next line if
-        // it's at the end of the current one already. AdjustCursorPos shouldn't
-        // to be doing anything funny, just moving the cursor to the location GetForwardTab returns
-        Status = AdjustCursorPosition(_screenBuffer, cNewPos, TRUE, nullptr);
+        cursorPos = (fForward) ? _screenBuffer.GetForwardTab(cursorPos) : _screenBuffer.GetReverseTab(cursorPos);
     }
-    return Status;
+
+    return AdjustCursorPosition(_screenBuffer, cursorPos, TRUE, nullptr);
 }
 
 // Routine Description:

src/host/screenInfo.cpp

@@ -2219,12 +2219,7 @@ COORD SCREEN_INFORMATION::GetForwardTab(const COORD cCurrCursorPos) const noexce
 {
     COORD cNewCursorPos = cCurrCursorPos;
     SHORT sWidth = GetBufferSize().RightInclusive();
-    if (cCurrCursorPos.X == sWidth)
-    {
-        cNewCursorPos.X = 0;
-        cNewCursorPos.Y += 1;
-    }
-    else if (_tabStops.empty() || cCurrCursorPos.X >= _tabStops.back())
+    if (_tabStops.empty() || cCurrCursorPos.X >= _tabStops.back())
     {
         cNewCursorPos.X = sWidth;
     }
@@ -2235,7 +2230,8 @@ COORD SCREEN_INFORMATION::GetForwardTab(const COORD cCurrCursorPos) const noexce
         {
             if (*it > cCurrCursorPos.X)
             {
-                cNewCursorPos.X = *it;
+                // make sure we don't exceed the width of the buffer
+                cNewCursorPos.X = std::min(*it, sWidth);
                 break;
             }
         }

src/host/ut_host/ScreenBufferTests.cpp

@@ -597,6 +597,19 @@ void ScreenBufferTests::TestGetForwardTab()
                          L"Cursor advanced to end of screen buffer.");
     }
 
+    Log::Comment(L"Find next tab from rightmost column.");
+    {
+        coordCursor.X = coordScreenBufferSize.X - 1;
+
+        COORD coordCursorExpected;
+        coordCursorExpected = coordCursor;
+
+        COORD const coordCursorResult = si.GetForwardTab(coordCursor);
+        VERIFY_ARE_EQUAL(coordCursorExpected,
+                         coordCursorResult,
+                         L"Cursor remains in rightmost column.");
+    }
+
     si._tabStops.clear();
 }