(cJSON) Enum Conversion Will Default to First Enum When Invalid or null data is provided

[pseudotronics]

I have run into an issue where the cJSON implementation of enums produces what to me is an unacceptable result.

Take for instance the following enum:

        "subscription": {
            "type": "string",
            "enum": [
                "state",
                "config",
                "heartbeat"
            ]
        }

The current cJSON implementation produces this result:

enum Subscription {
    SUBSCRIPTION_CONFIG,
    SUBSCRIPTION_HEARTBEAT,
    SUBSCRIPTION_STATE
};

enum Subscription cJSON_GetSubscriptionValue(const cJSON * j) {
    enum Subscription x = 0;
    if (NULL != j) {
        if (!strcmp(cJSON_GetStringValue(j), "config")) x = SUBSCRIPTION_CONFIG;
        else if (!strcmp(cJSON_GetStringValue(j), "heartbeat")) x = SUBSCRIPTION_HEARTBEAT;
        else if (!strcmp(cJSON_GetStringValue(j), "state")) x = SUBSCRIPTION_STATE;
    }
    return x;
}

The problem is that 0 is SUBSCRIPTION_CONFIG. That means when the subscription is null or something undefined the value returned is always SUBSCRIPTION_CONFIG.

The easiest way to correct this would be to always set the first enum = 1 when declaring the enum.

enum Subscription {
    SUBSCRIPTION_CONFIG = 1,
    SUBSCRIPTION_HEARTBEAT,
    SUBSCRIPTION_STATE
};

I have this implemented as a styling option in my fork, but I am unsure if this is the best approach. I don't fully understand the base enum definition in quicktype. It looks like there is a provision for assigning values baked in, but I could not figure out how to make that happen.

Here is the relevant emit block that appears to have provision for emitting the enum with a value. I added the first ? " = 1" : "" but like i said before I am unsure if this is a good approach.

        this.emitBlock(
            ["enum ", enumName],
            () => {
                const combinedName = allUpperWordStyle(this.sourcelikeToString(enumName));
                this.forEachEnumCase(enumType, "none", (name, jsonName) => {
                    if (enumValues !== undefined) {
                        const [enumValue] = getAccessorName(enumValues, jsonName);
                        if (enumValue !== undefined) {
                            this.emitLine(combinedName, "_", name, " = ", enumValue.toString(), ",");
                        } else {
                            this.emitLine(combinedName, "_", name, first ? " = 1" : "", ",");
                        }
                    } else {
                        this.emitLine(combinedName, "_", name, first ? " = 1" : "", ",");
                    }
                    first = false;
                });
            },
            "",
            true
        );