OrchardCMS/OrchardCore · error · ArgumentException

Invalid regexp query

Error message

Invalid regexp query

What it means

RegexpQueryProvider.CreateQuery dispatches on the JSON value kind; a regexp query must be a JSON object node. Any other value kind falls to the switch default and throws ArgumentException. This mirrors the other Lucene query providers' validation style.

Solutions

1. Use the object form: {"field": {"type": "regexp", "value": "pattern"}}.
2. Inspect the incoming JSON to find the malformed field node.
3. Fix the query-producing code to wrap regexp specs in objects.

Example fix

// before
{"Title": "Orch.*"}
// after
{"Title": {"type": "regexp", "value": "Orch.*"}}

if (node?.GetValueKind() == JsonValueKind.Object) { /* safe to call */ }

static bool IsRegexpQueryObject(JsonNode node) => node is JsonObject o && o.TryGetPropertyValue("type", out var t) && t.GetValueKind() == JsonValueKind.String && t.GetValue<string>() == "regexp";

try { var q = provider.CreateQuery(node); } catch (ArgumentException ex) when (ex.Message == "Invalid regexp query") { // inspect and log the offending node }

When it happens

Trigger: Passing {"field": "pattern"} or {"field": ["a", "b"]} where an object node with type 'regexp' is required.

Common situations: Query builders emitting plain values instead of the discriminated object; copy-paste between term and regexp syntax; corrupted saved queries.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• Invalid prefix query
• Invalid range query
• Invalid term query
• Missing value in regexp query
• Invalid fuzzy query

AI-assisted analysis of OrchardCMS/OrchardCore@4306c0717f (2026-09-13). Data as JSON: /api/errors/c4f191cf2163e905. Report an issue: GitHub.

Appendix: source

Thrown at src/OrchardCore/OrchardCore.Lucene.Core/QueryProviders/RegexpQueryProvider.cs:42

            case JsonValueKind.Object:
                var obj = first.Value.AsObject();

                if (!obj.TryGetPropertyValue("value", out var value))
                {
                    throw new ArgumentException("Missing value in regexp query");
                }

                // TODO: Support flags

                var regexpQuery = new RegexpQuery(new Term(first.Key, value.Value<string>()));

                if (obj.TryGetPropertyValue("boost", out var boost))
                {
                    regexpQuery.Boost = boost.Value<float>();
                }

                return regexpQuery;
            default: throw new ArgumentException("Invalid regexp query");
        }
    }
}

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