comctl32: treeview: Fix crash when deleting the first visible item while bRedraw == false (try 2)

[Joachim Priesner]

When bRedraw == false, TREEVIEW_DeleteItem returned early, leaving
firstVisible == NULL. This led to a crash when bRedraw was set to true
again.

Try 2: fix style issues in unit test reported by Nikolay Sivov
(thanks for the review).

Signed-off-by: Joachim Priesner <joachim.priesner at web.de>
---
 dlls/comctl32/tests/treeview.c | 33 +++++++++++++++++++++++++++++++++
 dlls/comctl32/treeview.c       |  4 +++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/dlls/comctl32/tests/treeview.c b/dlls/comctl32/tests/treeview.c
index 92504c1..bd030d6 100644
--- a/dlls/comctl32/tests/treeview.c
+++ b/dlls/comctl32/tests/treeview.c
@@ -1878,8 +1878,13 @@ static void test_delete_items(void)
 {
     const struct message *msg;
     HWND hTree;
+    HTREEITEM hItem1, hItem2;
+    TVINSERTSTRUCTA ins;
     INT ret;
 
+    static CHAR item1[] = "Item 1";
+    static CHAR item2[] = "Item 2";
+
     hTree = create_treeview_control(0);
     fill_tree(hTree);
 
@@ -1901,6 +1906,34 @@ static void test_delete_items(void)
     ok(ret == 0, "got %d\n", ret);
 
     DestroyWindow(hTree);
+
+    /* Regression test for a crash when deleting the first visible item while bRedraw == false. */
+    hTree = create_treeview_control(0);
+
+    ins.hParent = TVI_ROOT;
+    ins.hInsertAfter = TVI_ROOT;
+    U(ins).item.mask = TVIF_TEXT;
+    U(ins).item.pszText = item1;
+    hItem1 = TreeView_InsertItemA(hTree, &ins);
+    ok(hItem1 != NULL, "InsertItem failed\n");
+
+    ins.hParent = TVI_ROOT;
+    ins.hInsertAfter = hItem1;
+    U(ins).item.mask = TVIF_TEXT;
+    U(ins).item.pszText = item2;
+    hItem2 = TreeView_InsertItemA(hTree, &ins);
+    ok(hItem2 != NULL, "InsertItem failed\n");
+
+    ret = SendMessageA(hTree, WM_SETREDRAW, FALSE, 0);
+    ok(ret == 0, "got %d\n", ret);
+
+    ret = SendMessageA(hTree, TVM_DELETEITEM, 0, (LPARAM)hItem1);
+    ok(ret == TRUE, "got %d\n", ret);
+
+    ret = SendMessageA(hTree, WM_SETREDRAW, TRUE, 0);
+    ok(ret == 0, "got %d\n", ret);
+
+    DestroyWindow(hTree);
 }
 
 static void test_cchildren(void)
diff --git a/dlls/comctl32/treeview.c b/dlls/comctl32/treeview.c
index 695745c..1ce94da 100644
--- a/dlls/comctl32/treeview.c
+++ b/dlls/comctl32/treeview.c
@@ -1577,11 +1577,13 @@ TREEVIEW_DeleteItem(TREEVIEW_INFO *infoPtr, HTREEITEM item)
 
     TREEVIEW_VerifyTree(infoPtr);
 
+    if (visible)
+        TREEVIEW_SetFirstVisible(infoPtr, newFirstVisible, TRUE);
+
     if (!infoPtr->bRedraw) return TRUE;
 
     if (visible)
     {
-       TREEVIEW_SetFirstVisible(infoPtr, newFirstVisible, TRUE);
        TREEVIEW_RecalculateVisibleOrder(infoPtr, prev);
        TREEVIEW_UpdateScrollBars(infoPtr);
        TREEVIEW_Invalidate(infoPtr, NULL);
-- 
2.1.4