sveltejs/kit · error · Error

incorrect_fail_message (form action returned an ActionFailur

Error message

incorrect_fail_message (form action returned an ActionFailure from a remote form function, dev-only)

What it means

Dev-only diagnostic inside remote form handling: after invoking the remote form function, its return value was an ActionFailure. Remote form functions replaced classic form actions and must surface invalid state via the provided `issue` callback (create_issues), not by returning or throwing fail(); this guard replaces the opaque failure with the shared incorrect_fail_message so the developer sees the real mistake.

Source

Thrown at packages/kit/src/runtime/app/server/remote/form.js:127

					handle_issues(output, validated.issues, form_data, __.id);
				} else {
					if (validated !== undefined) {
						data = validated.value;
					}

					const issue = create_issues();

					try {
						output.result = await run_remote_function(
							event,
							state,
							true,
							() => data,
							(data) => (!maybe_fn ? fn() : fn(data, issue))
						);

						if (DEV && output.result instanceof ActionFailure) {
							throw new Error(incorrect_fail_message);
						}
					} catch (e) {
						if (e instanceof ValidationError) {
							handle_issues(output, e.issues, form_data, __.id);
						} else if (DEV && e instanceof ActionFailure) {
							throw new Error(incorrect_fail_message, { cause: e });
						} else {
							throw e;
						}
					}
				}

				// We don't need to care about args or deduplicating calls, because uneval results are only relevant in full page reloads
				// where only one form submission is active at the same time
				if (!event.isRemoteRequest) {
					const cache = get_cache(__, state);
					cache[''] ??= output;

View on GitHub (pinned to 03f1687fe6)

Solutions

1. Replace `return fail(...)` with the issue callback passed to the form function, e.g. issue('field', 'message')
2. Return normal data from the remote form function and report validation problems via create_issues

When it happens

Trigger: Thrown at packages/kit/src/runtime/app/server/remote/form.js:127 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/cb01c42a74bfa5bd. Report an issue: GitHub.