t8y2/dbx · error · java.lang.IllegalArgumentException

Index specification is required

Error message

Index specification is required

What it means

If the dropIndex/dropIndexes argument parses to a JSON object (a key-pattern index specification), that object must contain at least one key. An empty document {} cannot identify any index, so the agent throws before issuing the drop command.

Source

Thrown at agents/drivers/mongodb/src/main/java/com/dbx/agent/mongodb/MongoAgent.java:1389

        JsonElement value = JsonParser.parseString(indexesJson);
        if (value.isJsonPrimitive() && value.getAsJsonPrimitive().isString()) {
            String name = value.getAsString();
            if (name.isBlank()) {
                throw new IllegalArgumentException("Index name is required");
            }
            if (single && "*".equals(name)) {
                throw new IllegalArgumentException("dropIndex does not accept \"*\"; use dropIndexes() or dropIndexes(\"*\") instead");
            }
            if (DEFAULT_ID_INDEX_NAME.equals(name)) {
                throw new IllegalArgumentException("The default MongoDB _id_ index cannot be dropped");
            }
            return name;
        }
        if (value.isJsonObject()) {
            JsonObject object = value.getAsJsonObject();
            if (object.size() == 0) {
                throw new IllegalArgumentException("Index specification is required");
            }
            Document specification = Document.parse(indexesJson);
            if (isDefaultIdIndexSpecification(specification)) {
                throw new IllegalArgumentException("The default MongoDB _id_ index cannot be dropped");
            }
            return specification;
        }
        if (value.isJsonArray()) {
            if (single) {
                throw new IllegalArgumentException("dropIndex only accepts a string index name or JSON document; arrays are not supported");
            }
            List<String> names = new ArrayList<>();
            value.getAsJsonArray().forEach(item -> {
                if (!item.isJsonPrimitive() || !item.getAsJsonPrimitive().isString() || item.getAsString().isBlank()) {
                    throw new IllegalArgumentException("dropIndexes only accepts arrays of string index names");
                }
                names.add(item.getAsString());
            });

View on GitHub (pinned to c0390bff16)

Solutions

1. Provide the key pattern of the index, e.g. {"createdAt": 1}
2. Confirm the map/object used to build the spec is populated
3. Prefer passing the index name string from listIndexes when known

Example fix

// before
Map<String,Integer> keys = indexKeysFromConfig(); // may be empty
agent.execute("dropIndex", Map.of("indexes", gson.toJson(keys)));
// after
Map<String,Integer> keys = indexKeysFromConfig();
if (!keys.isEmpty()) {
    agent.execute("dropIndex", Map.of("indexes", gson.toJson(keys)));
} else {
    throw new IllegalStateException("index key pattern not configured");
}

Document keyPattern = Document.parse(indexesJson);
if (keyPattern.isEmpty()) {
    throw new IllegalArgumentException("index key pattern must have at least one key");
}

boolean isNonEmptyKeySpec(Map<String,?> keys) {
    return keys != null && !keys.isEmpty();
}

try {
    agent.execute("dropIndex", params);
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("Index specification is required")) {
        throw new IllegalStateException("configured key pattern was empty", e);
    } else { throw e; }
}

When it happens

Trigger: Calling dropIndex/dropIndexes with indexes="{}" or an object serialized from an empty map (e.g. JSON.stringify({}) from a JS caller, or an unset map variable).

Common situations: Building the key pattern dynamically and the underlying map ending up empty; partial deserialization dropping all keys; templating placeholder replaced with an empty object.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• dropIndex requires a string index name or JSON document
• Index name is required
• Target collection name must differ from the source collectio
• dropIndex does not accept "*"; use dropIndexes() or dropInde
• The default MongoDB _id_ index cannot be dropped

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/f5e738c31d39f432. Report an issue: GitHub.