glanceapp/glance · error

initializing default theme: %v

Error message

initializing default theme: %v

What it means

Startup fails when the top-level `theme` configuration's init() errors. After presets are merged, glance sets Theme.Key to "default" and initializes the active theme — compiling its CSS/preview templates and resolving its colors. The chained %v error comes from that same init() path: bad color values, an invalid `default` preset reference, or a template failure.

Source

Thrown at internal/glance/glance.go:140

		})

		themePresets, err := newOrderedYAMLMap(themeKeys, themeProps)
		if err != nil {
			return nil, fmt.Errorf("creating theme presets: %v", err)
		}
		config.Theme.Presets = *themePresets.Merge(&config.Theme.Presets)

		for key, properties := range config.Theme.Presets.Items() {
			properties.Key = key
			if err := properties.init(); err != nil {
				return nil, fmt.Errorf("initializing preset theme %s: %v", key, err)
			}
		}
	}

	config.Theme.Key = "default"
	if err := config.Theme.init(); err != nil {
		return nil, fmt.Errorf("initializing default theme: %v", err)
	}

	//
	// Init pages
	//

	app.slugToPage[""] = &config.Pages[0]

	providers := &widgetProviders{
		assetResolver: app.StaticAssetPath,
	}

	for p := range config.Pages {
		page := &config.Pages[p]
		page.PrimaryColumnIndex = -1

		if page.Slug == "" {
			page.Slug = titleToSlug(page.Title)

View on GitHub (pinned to 91324e8de7)

Solutions

1. Read the chained error for the specific failing field or template
2. Validate each top-level theme field against the docs: color-scheme in {light, dark}, colors in supported formats, multipliers numeric
3. Temporarily remove custom theme overrides to confirm the default theme starts, then re-add fields one by one

Example fix

# before
theme:
  background-color: 151519   # missing '#'
# after
theme:
  background-color: "#151519"

// Validate top-level theme fields before startup
var t struct{ ColorScheme string `yaml:"color-scheme"`; BackgroundColor string `yaml:"background-color"` }
yaml.Unmarshal(cfg, &struct{ Theme typeof(t) `yaml:"theme"` }{}) // or inline struct
if t.ColorScheme != "" && t.ColorScheme != "light" && t.ColorScheme != "dark" { return errors.New("theme.color-scheme invalid") }

func validHex(s string) bool { if s == "" { return true }; _, err := colorful.Hex(s); return err == nil }

Fail fast with the chained init() cause; surface which theme field is implicated rather than retrying startup.

When it happens

Trigger: Setting top-level theme fields (color-scheme, background-color, primary-color, negative-color, contrast-multiplier, text-saturation-multiplier) to invalid values, or referencing `presets` data that breaks the merged theme's template rendering.

Common situations: A global theme typo like `color-scheme: darkk`; a hex color missing the '#'; copy-pasting theme blocks from a glance version whose template expects different fields; invalid float values for multipliers.

Related errors

• initializing preset theme %s: %v
• secret-key must be exactly %d bytes
• validating config file: %w
• URL is required
• nested groups are not supported

AI-assisted analysis of glanceapp/glance@91324e8de7 (2026-08-15). Data as JSON: /api/errors/c211e88797b57dd7. Report an issue: GitHub.