attribute view custom colors count exceeds the

Error message

attribute view custom colors count exceeds the %d item limit

What it means

NormalizeAttributeViewCustomColors validates and normalizes a database (attribute view) custom color list. In strict mode, if the input list contains more than MaxCustomColors entries, it rejects the entire list rather than truncating. This protects the persisted palette configuration from silently growing beyond the supported limit.

Solutions

Trim the colors slice to at most MaxCustomColors entries before calling the API
Merge duplicate or unused colors to reduce the count below the limit
If the palette came from a config/history file, remove excess entries from that file

Example fix

// before
ret, err := av.NormalizeAttributeViewCustomColors(colors, true)
// after
if len(colors) > av.MaxCustomColors {
    colors = colors[:av.MaxCustomColors]
}
ret, err := av.NormalizeAttributeViewCustomColors(colors, true)

Defensive patterns

Strategy: validation

Validate before calling

if len(colors) > av.MaxCustomColors {
    return fmt.Errorf("too many colors: %d > %d", len(colors), av.MaxCustomColors)
}

Try / catch

if _, err := av.NormalizeAttributeViewCustomColors(colors, true); err != nil {
    if strings.Contains(err.Error(), "item limit") { colors = colors[:av.MaxCustomColors] }
}

Prevention

Check len(colors) against MaxCustomColors before appending
Merge duplicate colors instead of adding new entries
Never hand-edit palette files without counting entries

When it happens

Trigger: Calling setAttrViewCustomColors, customColorPalette, or decodeHistoricalWorkspacePalette with a palette whose length exceeds MaxCustomColors while strict=true; decoding a workspace palette file that was hand-edited or produced by an older/newer version without the cap.

Common situations: Hand-editing the workspace palette JSON and adding too many colors; importing palette settings from another workspace or version that did not enforce the limit; plugin code appending custom colors without checking MaxCustomColors.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/d58892a4d5909f85. Report an issue: GitHub.

Appendix: source

Thrown at kernel/av/color.go:96

// UnmarshalJSON 忽略外部输入中的派生颜色，派生颜色只能由内核根据数据库调色板生成。
func (value *ValueSelect) UnmarshalJSON(data []byte) error {
	decoded := struct {
		Content string `json:"content"`
		Color   string `json:"color"`
	}{}
	if err := json.Unmarshal(data, &decoded); nil != err {
		return err
	}
	value.Content = decoded.Content
	value.Color = decoded.Color
	value.ResolvedColor = nil
	return nil
}

// NormalizeAttributeViewCustomColors 校验并规范化数据库自定义颜色。
func NormalizeAttributeViewCustomColors(colors []*AttributeViewCustomColor, strict bool) (ret []*AttributeViewCustomColor, err error) {
	if strict && MaxCustomColors < len(colors) {
		return nil, fmt.Errorf("attribute view custom colors count exceeds the %d item limit", MaxCustomColors)
	}

	indexes := map[int]struct{}{}
	for _, color := range colors {
		normalized, normalizeErr := normalizeAttributeViewCustomColor(color)
		if nil != normalizeErr {
			if strict {
				return nil, normalizeErr
			}
			continue
		}
		if _, ok := indexes[normalized.Index]; ok {
			if strict {
				return nil, fmt.Errorf("duplicated attribute view custom color index [%d]", normalized.Index)
			}
			continue
		}
		indexes[normalized.Index] = struct{}{}

View on GitHub (pinned to 9f775e8a12)