Client: Send exposeEvent to parent on subsurface position changes

When a subsurface is moved, we need the parent window to commit to apply
that move. Ideally we want this in sync with any potential rendering on
the parent window.

Currently the code calls requestUpdate() which acts more like a frame
callback; it will only do something if the main QWindow considers itself
dirty.

We want to force a repaint, which is semantically more similar to an
ExposeEvent.

Fixes: QTBUG-86177
Pick-to: 5.15
Change-Id: I30bdfa357beee860ce2b00a256eaea6d040dd55c
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

1 files changed, 28 insertions, 5 deletions

diff --git a/tests/auto/client/surface/tst_surface.cpp b/tests/auto/client/surface/tst_surface.cpp
index c7b02e2c..60d89132 100644
--- a/tests/auto/client/surface/tst_surface.cpp
+++ b/tests/auto/client/surface/tst_surface.cpp
@@ -165,17 +165,40 @@ void tst_surface::negotiateShmFormat()
 void tst_surface::createSubsurface()
 {
     QRasterWindow window;
-    window.resize(64, 64);
-    window.show();
-    QCOMPOSITOR_TRY_VERIFY(xdgToplevel());
-    exec([=] { xdgToplevel()->sendCompleteConfigure(); });
-    QCOMPOSITOR_TRY_VERIFY(xdgSurface()->m_committedConfigureSerial);
+    window.setObjectName("main");
+    window.resize(200, 200);
 
     QRasterWindow subWindow;
+    subWindow.setObjectName("subwindow");
     subWindow.setParent(&window);
     subWindow.resize(64, 64);
+
+    window.show();
     subWindow.show();
+
     QCOMPOSITOR_TRY_VERIFY(subSurface());
+    QCOMPOSITOR_TRY_VERIFY(xdgToplevel());
+    exec([=] { xdgToplevel()->sendCompleteConfigure(); });
+    QCOMPOSITOR_TRY_VERIFY(xdgSurface()->m_committedConfigureSerial);
+
+    const Surface *mainSurface = exec([=] {return surface(0);});
+    const Surface *childSurface = exec([=] {return surface(1);});
+    QSignalSpy  mainSurfaceCommitSpy(mainSurface, &Surface::commit);
+    QSignalSpy childSurfaceCommitSpy(childSurface, &Surface::commit);
+
+    // Move subsurface. The parent should redraw and commit
+    subWindow.setGeometry(100, 100, 64, 64);
+    // the toplevel should commit to indicate the subsurface moved
+    QCOMPOSITOR_TRY_COMPARE(mainSurfaceCommitSpy.count(), 1);
+    mainSurfaceCommitSpy.clear();
+    childSurfaceCommitSpy.clear();
+
+    // Move and resize the subSurface. The parent should redraw and commit
+    // The child should also redraw
+    subWindow.setGeometry(50, 50, 80, 80);
+    QCOMPOSITOR_TRY_COMPARE(mainSurfaceCommitSpy.count(), 1);
+    QCOMPOSITOR_TRY_COMPARE(childSurfaceCommitSpy.count(), 1);
+
 }
 
 // Used to cause a crash in libwayland (QTBUG-79674)