Merge ~3v1n0/unity:decorations-empty-shape-fix into unity:master

[Marco Trevisan (Treviño)]

diff --git a/debian/changelog b/debian/changelog
index cc2e91c..a06bad7 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,18 @@
+unity (7.5.1+22.04.20211026-0ubuntu1) UNRELEASED; urgency=medium
+
+  [ Uladzislau Nikalayevich ]
+  * DecoratedWindow: Do not try to use shaped shadows on empty quads.
+    Windows may have no shaped rectangles, but we're still trying to set
+    them. This is because we might not initialize the shape size, leading
+    to invalid values. (LP: #1904337)
+
+  [ Marco Trevisan (Treviño) ]
+  * DecorationsShape: Initialize parameters on missing rectangles.
+    In such case the shape should just be empty, but we didn't really handle
+    the case properly.
+
+ -- Marco Trevisan (Treviño) <[e-mail]>  Tue, 26 Oct 2021 14:25:06 +0200
+
 unity (7.5.1+21.10.20210601.1-0ubuntu1) impish; urgency=medium
 
   * New upstream release
diff --git a/decorations/DecoratedWindow.cpp b/decorations/DecoratedWindow.cpp
index ed5548f..21f192c 100644
--- a/decorations/DecoratedWindow.cpp
+++ b/decorations/DecoratedWindow.cpp
@@ -750,6 +750,12 @@ void Window::Impl::ComputeShapedShadowQuad()
   unsigned int radius = active() ? manager_->active_shadow_radius() : manager_->inactive_shadow_radius();
 
   Shape shape(win_->id());
+  if (shape.GetRectangles().empty())
+  {
+    shaped_shadow_pixmap_.reset();
+    return;
+  }
+
   auto const& border = win_->borderRect();
   auto const& shadow_offset = manager_->shadow_offset();
 
diff --git a/decorations/DecorationsShape.cpp b/decorations/DecorationsShape.cpp
index bd827d7..0c5395e 100644
--- a/decorations/DecorationsShape.cpp
+++ b/decorations/DecorationsShape.cpp
@@ -61,6 +61,11 @@ Shape::Shape(Window xid)
   }
   else
   {
+    width_ = 0;
+    height_ = 0;
+    xoffs_ = 0;
+    yoffs_ = 0;
+
     LOG_ERROR(logger) << "XShapeQueryExtend returned no extents";
     return;
   }