[PATCH 0/1] MR9851: win32u: Return failure from ResizePalette called with a count of zero.

[Bernhard Übelacker (＠bernhardu)]

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=59203

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9851

[PATCH 1/1] win32u: Return failure from ResizePalette called with a count of zero.

[Bernhard Übelacker]

From: Bernhard Übelacker <[e-mail]>

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=59203
---
 dlls/gdi32/tests/palette.c | 30 ++++++++++++++++++++++++++++++
 dlls/win32u/palette.c      |  2 +-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/dlls/gdi32/tests/palette.c b/dlls/gdi32/tests/palette.c
index aac16097fba..e5342eb9dff 100644
--- a/dlls/gdi32/tests/palette.c
+++ b/dlls/gdi32/tests/palette.c
@@ -327,10 +327,40 @@ static void test_system_palette_entries(void)
     check_system_palette_entries(ULongToHandle(0xdeadbeef));
 }
 
+static void test_resize_palette(void)
+{
+    char logpalettebuf[sizeof(LOGPALETTE) + sizeof(logpalettedata)];
+    PLOGPALETTE logpalette = (PLOGPALETTE)logpalettebuf;
+    HPALETTE hpal;
+    PALETTEENTRY palette_entries[11];
+    int ret;
+
+    /* Initialize the logical palette with a few colours */
+    logpalette->palVersion = 0x300;
+    logpalette->palNumEntries = 8;
+    memcpy( logpalette->palPalEntry, logpalettedata, sizeof(logpalettedata) );
+
+    hpal = CreatePalette( logpalette );
+    ok(hpal != NULL, "CreatePalette failed.\n");
+    ret = GetPaletteEntries(hpal, 0, 11, palette_entries);
+    ok(ret == 8, "GetPaletteEntries returned %d entries, expected 8\n", ret);
+
+    ok(ResizePalette(hpal, 10), "ResizePalette failed.\n");
+    ret = GetPaletteEntries(hpal, 0, 11, palette_entries);
+    ok(ret == 10, "GetPaletteEntries returned %d entries, expected 10\n", ret);
+
+    ok(!ResizePalette(hpal, 0), "ResizePalette failed.\n");
+    ret = GetPaletteEntries(hpal, 0, 11, palette_entries);
+    ok(ret == 10, "GetPaletteEntries returned %d entries, expected 10\n", ret);
+
+    ok(DeleteObject(hpal), "DeleteObject failed.\n");
+}
+
 START_TEST(palette)
 {
     test_DIB_PAL_COLORS();
     test_palette_entries();
     test_halftone_palette();
     test_system_palette_entries();
+    test_resize_palette();
 }
diff --git a/dlls/win32u/palette.c b/dlls/win32u/palette.c
index 4809b954fdf..6db9aa7b35d 100644
--- a/dlls/win32u/palette.c
+++ b/dlls/win32u/palette.c
@@ -224,7 +224,7 @@ BOOL WINAPI NtGdiResizePalette( HPALETTE hPal, UINT count )
     PALETTEOBJ * palPtr = GDI_GetObjPtr( hPal, NTGDI_OBJ_PAL );
     PALETTEENTRY *entries;
 
-    if( !palPtr ) return FALSE;
+    if( !palPtr || count == 0 ) return FALSE;
     TRACE("hpal = %p, prev = %i, new = %i\n", hPal, palPtr->count, count );
 
     if (!(entries = realloc( palPtr->entries, count * sizeof(*palPtr->entries) )))
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/9851

[Alfred Agrell (＠Alcaro)]

Alfred Agrell (@Alcaro) commented about dlls/gdi32/tests/palette.c:
> +
> +    /* Initialize the logical palette with a few colours */
> +    logpalette->palVersion = 0x300;
> +    logpalette->palNumEntries = 8;
> +    memcpy( logpalette->palPalEntry, logpalettedata, sizeof(logpalettedata) );
> +
> +    hpal = CreatePalette( logpalette );
> +    ok(hpal != NULL, "CreatePalette failed.\n");
> +    ret = GetPaletteEntries(hpal, 0, 11, palette_entries);
> +    ok(ret == 8, "GetPaletteEntries returned %d entries, expected 8\n", ret);
> +
> +    ok(ResizePalette(hpal, 10), "ResizePalette failed.\n");
> +    ret = GetPaletteEntries(hpal, 0, 11, palette_entries);
> +    ok(ret == 10, "GetPaletteEntries returned %d entries, expected 10\n", ret);
> +
> +    ok(!ResizePalette(hpal, 0), "ResizePalette failed.\n");
> shouldn't that be 'unexpectedly succeeded'?

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9851#note_126374

[Bernhard Übelacker (＠bernhardu)]

On Sat Jan  3 00:37:05 2026 +0000, Alfred Agrell wrote:
> shouldn't that be 'unexpectedly succeeded'?
> Thanks for spotting, have not changed it when copying. Will push a v2 with this fixed.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9851#note_126375