Harden against resizing down to 0 columns/rows (#14467)

This changeset includes various guards against resizing the terminal down to 0
columns/rows: The 2 `TextBuffer` locations that accept new sizes, as well as
the `HwndTerminal::Refresh` which was the entrypoint causing the issue.

Closes #14404

(cherry picked from commit c5d417f)
Service-Card-Id: 87020511
Service-Version: 1.16

src/buffer/out/textBuffer.cpp

@@ -30,7 +30,7 @@ using PointTree = interval_tree::IntervalTree<til::point, size_t>;
 // Return Value:
 // - constructed object
 // Note: may throw exception
-TextBuffer::TextBuffer(const til::size screenBufferSize,
+TextBuffer::TextBuffer(til::size screenBufferSize,
                        const TextAttribute defaultAttributes,
                        const UINT cursorSize,
                        const bool isActiveBuffer,
@@ -46,6 +46,10 @@ TextBuffer::TextBuffer(const til::size screenBufferSize,
     _currentHyperlinkId{ 1 },
     _currentPatternId{ 0 }
 {
+    // Guard against resizing the text buffer to 0 columns/rows, which would break being able to insert text.
+    screenBufferSize.width = std::max(screenBufferSize.width, 1);
+    screenBufferSize.height = std::max(screenBufferSize.height, 1);
+
     // initialize ROWs
     _storage.reserve(gsl::narrow<size_t>(screenBufferSize.Y));
     for (til::CoordType i = 0; i < screenBufferSize.Y; ++i)
@@ -896,9 +900,11 @@ void TextBuffer::Reset()
 // - newSize - new size of screen.
 // Return Value:
 // - Success if successful. Invalid parameter if screen buffer size is unexpected. No memory if allocation failed.
-[[nodiscard]] NTSTATUS TextBuffer::ResizeTraditional(const til::size newSize) noexcept
+[[nodiscard]] NTSTATUS TextBuffer::ResizeTraditional(til::size newSize) noexcept
 {
-    RETURN_HR_IF(E_INVALIDARG, newSize.X < 0 || newSize.Y < 0);
+    // Guard against resizing the text buffer to 0 columns/rows, which would break being able to insert text.
+    newSize.width = std::max(newSize.width, 1);
+    newSize.height = std::max(newSize.height, 1);
 
     try
     {

src/cascadia/PublicTerminalCore/HwndTerminal.cpp

@@ -365,15 +365,20 @@ HRESULT HwndTerminal::Refresh(const til::size windowSize, _Out_ til::size* dimen
     const auto viewInPixels = Viewport::FromDimensions(windowSize);
     const auto vp = _renderEngine->GetViewportInCharacters(viewInPixels);
 
+    // Guard against resizing the window to 0 columns/rows, which the text buffer classes don't really support.
+    auto size = vp.Dimensions();
+    size.width = std::max(size.width, 1);
+    size.height = std::max(size.height, 1);
+
     // If this function succeeds with S_FALSE, then the terminal didn't
     //      actually change size. No need to notify the connection of this
     //      no-op.
     // TODO: MSFT:20642295 Resizing the buffer will corrupt it
     // I believe we'll need support for CSI 2J, and additionally I think
     //      we're resetting the viewport to the top
-    RETURN_IF_FAILED(_terminal->UserResize({ vp.Width(), vp.Height() }));
-    dimensions->X = vp.Width();
-    dimensions->Y = vp.Height();
+    RETURN_IF_FAILED(_terminal->UserResize(size));
+    dimensions->width = size.width;
+    dimensions->height = size.height;
 
     return S_OK;
 }
@@ -473,7 +478,7 @@ HRESULT _stdcall TerminalCalculateResize(_In_ void* terminal, _In_ til::CoordTyp
 {
     const auto publicTerminal = static_cast<const HwndTerminal*>(terminal);
 
-    const auto viewInPixels = Viewport::FromDimensions({ 0, 0 }, { width, height });
+    const auto viewInPixels = Viewport::FromDimensions({ width, height });
     const auto viewInCharacters = publicTerminal->_renderEngine->GetViewportInCharacters(viewInPixels);
 
     dimensions->X = viewInCharacters.Width();