[PATCH v6 3/5] comctl32/tests: Add tests for NULL strings with edit control GETTEXT message.

[Aida Jonikienė]

From: Aida Jonikienė

---
 dlls/comctl32/tests/edit.c | 13 +++++++++++++
 dlls/user32/winproc.c      |  8 ++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/dlls/comctl32/tests/edit.c b/dlls/comctl32/tests/edit.c
index bce0215ef19..92017c046b2 100644
--- a/dlls/comctl32/tests/edit.c
+++ b/dlls/comctl32/tests/edit.c
@@ -1470,6 +1470,19 @@ static void test_edit_control_6(void)
     ok(ret == strlen(str), "Expected %s, got len %ld\n", str, ret);
     ok(!strcmp(buf, str), "Expected %s, got %s\n", str, buf);

+    ret = SendMessageA(hWnd, WM_GETTEXT, MAXLEN, (LPARAM)NULL);
+    ok(ret == 0, "Expected 0, got len %ld\n", ret);
+    ret = SendMessageA(hWnd, WM_GETTEXT, 0, (LPARAM)NULL);
+    ok(ret == 0, "Expected 0, got len %ld\n", ret);
+
+    if (0) /* Crashes on Windows. */
+    {
+       ret = SendMessageW(hWnd, WM_GETTEXT, MAXLEN, (LPARAM)NULL);
+       ok(ret == 0, "Expected 0, got len %ld\n", ret);
+       ret = SendMessageW(hWnd, WM_GETTEXT, 0, (LPARAM)NULL);
+       ok(ret == 0, "Expected 0, got len %ld\n", ret);
+    }
+
     buf[0] = 0;
     ret = SendMessageA(hWnd, WM_DESTROY, 0, 0);
     todo_wine
diff --git a/dlls/user32/winproc.c b/dlls/user32/winproc.c
index 5678e75b4e9..1ce5c87f954 100644
--- a/dlls/user32/winproc.c
+++ b/dlls/user32/winproc.c
@@ -274,9 +274,13 @@ LRESULT WINPROC_CallProcAtoW( winproc_callback_t callback, HWND hwnd, UINT msg,
             LPSTR str = (LPSTR)lParam;
             DWORD len = wParam * sizeof(WCHAR);

-            if (!(ptr = get_buffer( buffer, sizeof(buffer), len ))) break;
+            if (!str)
+                ptr = NULL;
+            else if (!(ptr = get_buffer( buffer, sizeof(buffer), len )))
+                break;
+
             ret = callback( hwnd, msg, wParam, (LPARAM)ptr, result, arg );
-            if (wParam)
+            if (wParam && str)
             {
                 len = 0;
                 if (*result)