clockworklabs/SpacetimeDB · error · ArgumentOutOfRangeException

Unknown reducer {reducer}

Error message

Unknown reducer {reducer}

What it means

Error "Unknown reducer {reducer}" thrown in clockworklabs/SpacetimeDB.

Source

Thrown at crates/codegen/src/csharp.rs:1246

                output,
                "protected override bool Dispatch(IReducerEventContext context, Reducer reducer)"
            );
            indented_block(output, |output| {
                writeln!(output, "var eventContext = (ReducerEventContext)context;");
                writeln!(output, "return reducer switch {{");
                {
                    indent_scope!(output);
                    for reducer_name in
                        iter_reducers(module, options.visibility).map(|r| r.accessor_name.deref().to_case(Case::Pascal))
                    {
                        writeln!(
                            output,
                            "Reducer.{reducer_name} args => Reducers.Invoke{reducer_name}(eventContext, args),"
                        );
                    }
                    writeln!(
                        output,
                        r#"_ => throw new ArgumentOutOfRangeException("Reducer", $"Unknown reducer {{reducer}}")"#
                    );
                }
                writeln!(output, "}};");
            });
            writeln!(output);

            writeln!(output, "public SubscriptionBuilder SubscriptionBuilder() => new(this);");
            writeln!(
                output,
                "public event Action<ReducerEventContext, Exception> OnUnhandledReducerError"
            );
            indented_block(output, |output| {
                writeln!(output, "add => Reducers.InternalOnUnhandledReducerError += value;");
                writeln!(output, "remove => Reducers.InternalOnUnhandledReducerError -= value;");
            });
        });

        vec![OutputFile {

View on GitHub (pinned to 524b4487d9)

When it happens

Trigger: Thrown at crates/codegen/src/csharp.rs:1246 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of clockworklabs/SpacetimeDB@524b4487d9 (2026-08-16). Data as JSON: /api/errors/b6382319e8261ddd. Report an issue: GitHub.