HMCL-dev/HMCL · error · JsonParseException

The author name is null

Error message

The author name is null

What it means

Thrown by ThemePackAuthor.fromJson when LocalizedText.fromJson returns null for the "name" element — i.e. the name key exists but its content is empty or not decodable into a LocalizedText. The library treats a null decoded name as invalid rather than creating an author with no display name.

Solutions

  1. Set a concrete name value: {"author": {"name": "Alice"}}.
  2. If using the localized form, supply at least one locale entry, e.g. {"name": {"en": "Alice"}}.
  3. Remove the "name": null placeholder before packaging.
  4. Check LocalizedText.fromJson's accepted shapes and conform the name element to them.

Example fix

// before
{"author": {"name": null}}
// after
{"author": {"name": "Alice"}}
Defensive patterns

Strategy: validation

Validate before calling

boolean decodableName(JsonElement nameJson) {
    if (nameJson == null || nameJson.isJsonNull()) return false;
    if (nameJson.isJsonPrimitive()) return nameJson.getAsJsonPrimitive().isString() && !nameJson.getAsString().isBlank();
    return nameJson.isJsonObject();
}

Try / catch

try { ThemePackAuthor a = ThemePackAuthor.fromJson(json); } catch (JsonParseException e) { if ("The author name is null".equals(e.getMessage())) supplyDefaultName(); throw e; }

Prevention

When it happens

Trigger: Author object with a null or empty-structure name, e.g. {"author": {"name": null}} or {"author": {"name": {}}}, when ThemePackAuthor.fromJson decodes it.

Common situations: Templates that leave "name": null as a placeholder, programmatic manifest generation that skips filling the localized name, or JSON round-tripping that dropped the name value.

Understand the failure class

Background: "failed to unmarshal" / json.Unmarshal errors: why parsing a response into a Go struct fails and how to fix it — this error's family across 23 libraries.

Related errors

AI-assisted analysis of HMCL-dev/HMCL@24702dc5a0 (2026-09-10). Data as JSON: /api/errors/89d1e3a39b9662a7. Report an issue: GitHub.

Appendix: source

Thrown at HMCL/src/main/java/org/jackhuang/hmcl/theme/ThemePackAuthor.java:107

            try {
                return new ThemePackAuthor(LocalizedText.plain(primitive.getAsString()));
            } catch (IllegalArgumentException e) {
                throw new JsonParseException(e);
            }
        }

        if (!(json instanceof JsonObject jsonObject)) {
            throw new JsonParseException("Theme-pack author must be an object or a string");
        }

        JsonElement nameJson = jsonObject.get("name");
        if (nameJson == null) {
            throw new JsonParseException("Missing author name: " + json);
        }

        LocalizedText name = LocalizedText.fromJson(nameJson);
        if (name == null) {
            throw new JsonParseException("The author name is null");
        }

        try {
            return new ThemePackAuthor(name);
        } catch (IllegalArgumentException e) {
            throw new JsonParseException(e);
        }
    }

    /// Creates theme-pack author metadata.
    ///
    /// @param name the localized author display name
    public ThemePackAuthor {
        if (name.mayBeEmpty()) {
            throw new IllegalArgumentException("The author name cannot be empty");
        }
    }

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