HMCL-dev/HMCL · error · IllegalArgumentException

Unsupported theme brightness:

Error message

Unsupported theme brightness: 

What it means

Raised in parseBrightness() (called from readBrightness) when the serialized brightness string in the theme manifest does not match any known brightness token (e.g. dark/light or a recognized level name). Only enumerated brightness names are accepted; an arbitrary or misspelled token is rejected. The input at fault is the brightness field's string value.

Solutions

1. Use one of the supported brightness tokens (e.g. "dark", "light") in the theme manifest.
2. Fix the typo or casing of the brightness value so it matches a known token.
3. Remove the brightness field to fall back to the default brightness.

When it happens

Trigger: Thrown at HMCL/src/main/java/org/jackhuang/hmcl/theme/ThemeAppearance.java:378 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of HMCL-dev/HMCL@24702dc5a0 (2026-09-10). Data as JSON: /api/errors/5a68fd2f0066eb2d. Report an issue: GitHub.

Appendix: source

Thrown at HMCL/src/main/java/org/jackhuang/hmcl/theme/ThemeAppearance.java:378

        if (contrast.equals(Contrast.LOW)) {
            object.addProperty(FIELD_CONTRAST, "low");
        } else if (contrast.equals(Contrast.DEFAULT)) {
            object.addProperty(FIELD_CONTRAST, "standard");
        } else if (contrast.equals(Contrast.MEDIUM)) {
            object.addProperty(FIELD_CONTRAST, "medium");
        } else if (contrast.equals(Contrast.HIGH)) {
            object.addProperty(FIELD_CONTRAST, "high");
        } else {
            object.addProperty(FIELD_CONTRAST, contrast.getValue());
        }
    }

    /// Parses a serialized theme brightness value.
    private static Brightness parseBrightness(String value) {
        return switch (value.trim().toLowerCase(Locale.ROOT)) {
            case "light" -> Brightness.LIGHT;
            case "dark" -> Brightness.DARK;
            default -> throw new IllegalArgumentException("Unsupported theme brightness: " + value);
        };
    }

    /// Converts a controlled brightness value to its canonical JSON string.
    private static String toJsonBrightness(Brightness brightness) {
        return switch (brightness) {
            case LIGHT -> "light";
            case DARK -> "dark";
        };
    }
}

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