[PATCH v2 1/1] Revert "server: Don't invalidate the newly exposed child region on the parent if it doesn't clip children."

[Jinoh Kang]

From: Jinoh Kang

This reverts commit 33617af8145b6fadfe41d48968a728ff57b3064b.

Apparently, the aforementioned commit might cause the expose region to
be incorrectly computed when a window transitions from invisible state
to visible state.

The commit also had caused regression in the following apps:

- Wine regedit.exe (bug 54268)
- Dn-FamiTracker (bug 52903)
- Unity Assets Bundle Extractor (same cause behind bug 52903)

It appears that the commit catalyzes discovery of hidden bugs in Wine's
window repaint logic.  It's also possible that the algorithm for
computing the expose region is incomplete.

For these reasons, revert this commit for now.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54268
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52903
---
 dlls/comctl32/tests/edit.c | 2 +-
 dlls/user32/tests/msg.c    | 4 ++++
 server/window.c            | 6 ++++--
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/dlls/comctl32/tests/edit.c b/dlls/comctl32/tests/edit.c
index f45b898dc12..a44f48022cf 100644
--- a/dlls/comctl32/tests/edit.c
+++ b/dlls/comctl32/tests/edit.c
@@ -3548,7 +3548,7 @@ static void test_change_focus(void)
     flush_sequences(sequences, NUM_MSG_SEQUENCES);
     SetFocus(hwnd);
     while (PeekMessageA(&msg, 0, 0, 0, PM_REMOVE)) DispatchMessageA(&msg);
-    ok_sequence(sequences, COMBINED_SEQ_INDEX, setfocus_combined_seq, "Set focus", FALSE);
+    ok_sequence(sequences, COMBINED_SEQ_INDEX, setfocus_combined_seq, "Set focus", TRUE);

flush_sequences(sequences, NUM_MSG_SEQUENCES);
     SetFocus(parent_wnd);
diff --git a/dlls/user32/tests/msg.c b/dlls/user32/tests/msg.c
index 6faaa2c2f40..8813e56fb8f 100644
--- a/dlls/user32/tests/msg.c
+++ b/dlls/user32/tests/msg.c
@@ -9317,6 +9317,8 @@ static void subtest_swp_paint_regions_( int line, int wrap_toplevel, LPCSTR pare
             }
             else
             {
+                todo_wine_if( !EqualRect( &rect_old, &rect_new ) &&
+                              (extest->style & WS_CLIPCHILDREN) == 0 && !is_composited )
                 ok( !!rgn_ok, "Parent update region shall match expected region\n" );
             }

@@ -9378,6 +9380,8 @@ static void subtest_swp_paint_regions_( int line, int wrap_toplevel, LPCSTR pare
             }
             else
             {
+                todo_wine_if( !EqualRect( &rect_old, &rect_new ) &&
+                              (extest->style & WS_CLIPCHILDREN) == 0 && !is_composited )
                 ok( !!rgn_ok, "Child update region shall match expected region\n" );
             }

diff --git a/server/window.c b/server/window.c
index f713ed224aa..5dbe1cd1eb2 100644
--- a/server/window.c
+++ b/server/window.c
@@ -1766,8 +1766,10 @@ static struct region *expose_window( struct window *win, const rectangle_t *old_
         offset_region( new_vis_rgn, win->window_rect.left - old_window_rect->left,
                        win->window_rect.top - old_window_rect->top  );

-        if (is_composited ? union_region( new_vis_rgn, old_vis_rgn, new_vis_rgn )
-                          : subtract_region( new_vis_rgn, old_vis_rgn, new_vis_rgn ))
+        if (is_composited ? union_region( new_vis_rgn, old_vis_rgn, new_vis_rgn ) :
+            (win->parent->style & WS_CLIPCHILDREN) ?
+            subtract_region( new_vis_rgn, old_vis_rgn, new_vis_rgn ) :
+            xor_region( new_vis_rgn, old_vis_rgn, new_vis_rgn ))
         {
             if (!is_region_empty( new_vis_rgn ))
             {