babalae/better-genshin-impact · warning · FormatException

音符 {keys} 的时值缺少右方括号

Error message

音符 {keys} 的时值缺少右方括号

What it means

Thrown by MusicScoreParser.ParseYuanQinTokens(string) when a duration bracket '[' is opened but no matching ']' is found. The method uses sheet.IndexOf(']', index + 1) and throws if the result is -1.

Source

Thrown at BetterGenshinImpact/GameTask/Music/Service/MusicScoreParser.cs:312

                keys = sheet[(index + 1)..end];
                index = end + 1;
            }
            else
            {
                keys = sheet[index].ToString();
                index++;
            }

            if (index >= sheet.Length || sheet[index] != '[')
            {
                throw new FormatException($"音符 {keys} 缺少时值");
            }

            var bracketEnd = sheet.IndexOf(']', index + 1);
            if (bracketEnd < 0)
            {
                throw new FormatException($"音符 {keys} 的时值缺少右方括号");
            }

            var value = sheet[(index + 1)..bracketEnd];
            index = bracketEnd + 1;
            if (value is "^" or "&")
            {
                tokens.Add(new YuanQinToken(keys, 0, value));
                continue;
            }

            var separator = value.IndexOf('-');
            var denominatorText = separator >= 0 ? value[..separator] : value;
            var special = separator >= 0 ? value[(separator + 1)..] : "none";
            if (!double.TryParse(denominatorText, NumberStyles.Float, CultureInfo.InvariantCulture,
                    out var denominator))
            {
                throw new FormatException($"无法解析音符 {keys} 的时值：{value}");
            }

View on GitHub (pinned to a7cb36712d)

Solutions

  1. Find the unclosed '[' and add the matching ']' in the sheet string.
  2. Run a bracket-balance validator on the sheet before parsing.
  3. Check the PerformanceScore.Error property for context.
Defensive patterns

Strategy: validation

Validate before calling

// Check bracket balance
int openSq = sheet.Count(c => c == '[');
int closeSq = sheet.Count(c => c == ']');
if (openSq != closeSq) { logger.LogError("方括号不匹配"); }

Try / catch

var score = await parser.ParseAsync(path, rootFolder, ct);
if (!string.IsNullOrEmpty(score.Error)) { logger.LogWarning(score.Error); }

Prevention

When it happens

Trigger: A yuanqin sheet string where a '[' is not followed by ']'. For example, 'Q[1 W[2]' where the first bracket is never closed.

Common situations: Manual editing error; truncated sheet; copy-paste mistake that dropped the closing bracket.

Related errors

AI-assisted analysis of babalae/better-genshin-impact@a7cb36712d (2026-08-13). Data as JSON: /api/errors/eddc6ca6366cc0bf. Report an issue: GitHub.