[PATCH 1/1] comctl32/treeview: check for child item before SendExpanding

[Thomas Csovcsity]

From: Thomas Csovcsity

In TREEVIEW_Collapse the TREEVIEW_SendExpanding call could change the
item->firstChild value, therefore check it before for early return.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=23077
---
 dlls/comctl32/treeview.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/dlls/comctl32/treeview.c b/dlls/comctl32/treeview.c
index fb06a727748..eebf5e1f0bb 100644
--- a/dlls/comctl32/treeview.c
+++ b/dlls/comctl32/treeview.c
@@ -3392,12 +3392,17 @@ TREEVIEW_Collapse(TREEVIEW_INFO *infoPtr, TREEVIEW_ITEM *item,
     if (!TREEVIEW_HasChildren(infoPtr, item))
    return FALSE;

-    if (bUser && TREEVIEW_SendExpanding(infoPtr, item, action))
-        return TRUE;
-
+    /* 
+     * the child items may not actually exist, they could be virtual.
+     * Just use item->firstChild to check for physical children,
+     * before TREEVIEW_SendExpanding may change it.
+    */
     if (item->firstChild == NULL)
    return FALSE;

+    if (bUser && TREEVIEW_SendExpanding(infoPtr, item, action))
+        return TRUE;
+
     wasExpanded = (item->state & TVIS_EXPANDED) != 0;
     item->state &= ~TVIS_EXPANDED;