From 3a4497af32d3d793f3ba01b329281a7e97270271 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Mon, 6 Jan 2025 14:04:47 +0100
Subject: [PATCH] Constrain range of usable characters in romanised metadata to
 ASCII only

Closes https://github.com/ppy/osu/issues/31398.

Rationale given in issue.

Compare stable logic:

- https://github.com/peppy/osu-stable-reference/blob/2280c4c436f80d04f9c79d3c905db00ac2902273/osu!/GameModes/Edit/Forms/SongSetup.cs#L118-L122
- https://github.com/peppy/osu-stable-reference/blob/2280c4c436f80d04f9c79d3c905db00ac2902273/osu!common/Helpers/GeneralHelper.cs#L410-L423

The control character check is a bit gratuitous (text boxes will already
not allow insertion of those, see
https://github.com/ppy/osu-framework/blob/e05cb86ff64abd343de49a143ada9734fd160a0a/osu.Framework/Graphics/UserInterface/TextBox.cs#L92),
but as it's a general helper I figured might as well.
---
 osu.Game/Beatmaps/MetadataUtils.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/osu.Game/Beatmaps/MetadataUtils.cs b/osu.Game/Beatmaps/MetadataUtils.cs
index 89c821c16c..1d2a3b5d01 100644
--- a/osu.Game/Beatmaps/MetadataUtils.cs
+++ b/osu.Game/Beatmaps/MetadataUtils.cs
@@ -15,7 +15,7 @@ namespace osu.Game.Beatmaps
         /// Returns <see langword="true"/> if the character <paramref name="c"/> can be used in <see cref="BeatmapMetadata.Artist"/> and <see cref="BeatmapMetadata.Title"/> fields.
         /// Characters not matched by this method can be placed in <see cref="BeatmapMetadata.ArtistUnicode"/> and <see cref="BeatmapMetadata.TitleUnicode"/>.
         /// </summary>
-        public static bool IsRomanised(char c) => c <= 0xFF;
+        public static bool IsRomanised(char c) => char.IsAscii(c) && !char.IsControl(c);
 
         /// <summary>
         /// Returns <see langword="true"/> if the string <paramref name="str"/> can be used in <see cref="BeatmapMetadata.Artist"/> and <see cref="BeatmapMetadata.Title"/> fields.