From: "Roman Pišl" <rpisl@seznam.cz>
Subject: [PATCH] comctl32/edit: Initialize font metrics to nonzero in WM_NCCREATE.
Message-Id: <20200326194844.20058-1-rpisl@seznam.cz>
Date: Thu, 26 Mar 2020 20:48:44 +0100

v2: Introduced helper function.
v3: Improved helper function (I really didn't like the previous).
v4: Simpler and less intrusive solution (tested on all affected apps from bugzilla).

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=48803
Signed-off-by: Roman Pišl <rpisl@seznam.cz>
---
 dlls/comctl32/edit.c       |  7 +++++
 dlls/comctl32/tests/edit.c | 59 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/dlls/comctl32/edit.c b/dlls/comctl32/edit.c
index d02d7af7b9..3a1a5b791d 100644
--- a/dlls/comctl32/edit.c
+++ b/dlls/comctl32/edit.c
@@ -4488,6 +4488,13 @@ static LRESULT EDIT_WM_NCCreate(HWND hwnd, LPCREATESTRUCTW lpcs)
         else if (es->style & WS_BORDER)
 		SetWindowLongW(hwnd, GWL_STYLE, es->style & ~WS_BORDER);
 
+	/*
+	 * Initialize to avoid division by zero,
+	 * a proper value is set during WM_Create.
+	 */
+	es->line_height = 1;
+	es->char_width = 1;
+
 	return TRUE;
 
 cleanup:
diff --git a/dlls/comctl32/tests/edit.c b/dlls/comctl32/tests/edit.c
index cec6025077..3bfbee4ddd 100644
--- a/dlls/comctl32/tests/edit.c
+++ b/dlls/comctl32/tests/edit.c
@@ -1768,6 +1768,64 @@ static BOOL is_font_installed(const char*name)
     return ret;
 }
 
+static WNDPROC orig_class_proc;
+
+static LRESULT CALLBACK test_class_proc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
+{
+    RECT rect;
+    LRESULT result;
+
+    switch (message)
+    {
+        case WM_NCCREATE:
+            result = CallWindowProcA(orig_class_proc, hwnd, message, wParam, lParam);
+
+            memset(&rect, 0, sizeof(rect));
+            SendMessageA(hwnd, EM_GETRECT, 0, (LPARAM)&rect);
+            ok(!rect.right && !rect.bottom, "Invalid size after NCCREATE: %d x %d\n", rect.right, rect.bottom);
+
+            /* test that early messages don't crash or cause unexpected behavior */
+            SendMessageA(hwnd, EM_SETSEL, 0, 0);
+            SendMessageA(hwnd, WM_SIZE, 0, 0);
+
+            return result;
+
+        case WM_CREATE:
+            /* test that early messages don't crash or cause unexpected behavior */
+            SendMessageA(hwnd, EM_SETSEL, 0, 0);
+            SendMessageA(hwnd, WM_SIZE, 0, 0);
+
+            break;
+    }
+
+    return CallWindowProcA(orig_class_proc, hwnd, message, wParam, lParam);
+}
+
+static void test_early_messages(void)
+{
+    BOOL ret;
+    ATOM atom;
+    HWND hwEdit;
+    WNDCLASSA cls;
+
+    ret = GetClassInfoA(NULL, "Edit", &cls);
+    ok(ret, "Failed to get class info.\n");
+
+    orig_class_proc = cls.lpfnWndProc;
+    cls.lpfnWndProc = test_class_proc;
+    cls.lpszClassName = "TestClassName";
+
+    atom = RegisterClassA(&cls);
+    ok(atom != 0, "Failed to register class.\n");
+
+    hwEdit = CreateWindowExA(0, (LPCSTR)MAKEINTATOM(atom), "Text Text", ES_MULTILINE | WS_BORDER | ES_AUTOHSCROLL | ES_AUTOVSCROLL,
+        10, 10, 300, 300, NULL, NULL, hinst, NULL);
+    ok(hwEdit != NULL, "Failed to create a window.\n");
+
+    DestroyWindow(hwEdit);
+    UnregisterClassA((LPCSTR)MAKEINTATOM(atom), hinst);
+}
+
 static void test_margins(void)
 {
     DWORD old_margins, new_margins;
@@ -3393,6 +3451,7 @@ START_TEST(edit)
     test_edit_control_6();
     test_edit_control_limittext();
     test_edit_control_scroll();
+    test_early_messages();
     test_margins();
     test_margins_font_change();
     test_text_position();

-- 
2.20.1