can1357/oh-my-pi · error · TraversalError

TraversalError

Error message

TraversalError

What it means

`type.assert(data)` runs the type against the data and, if the result is an OmpErrors collection, throws a TraversalError aggregating all traversal problems. Unlike `.allows()` or `.run()`, assert is the throwing API: failures surface as a single TraversalError rather than a returned result.

Source

Thrown at packages/omptype/src/type.ts:1021

			const allows = compileAllows(this.ir);
			// Shadow the shared dispatcher once this schema has its specialized check.
			this.allows = allows;
			return allows(data);
		}
		for (const step of steps) {
			if (step.kind === "filter" && !step.fn(data, new Ctx(data))) return false;
		}
		const out = this[kBase](data);
		if (out instanceof OmpErrors) return false;
		for (const step of steps) {
			if (step.kind === "narrow" && !step.fn(out, new Ctx(out))) return false;
		}
		return true;
	},

	assert(this: InternalType, data: unknown): unknown {
		const out = this.run(data);
		if (out instanceof OmpErrors) throw new TraversalError(out);
		return out;
	},

	from(this: InternalType, data: unknown): unknown {
		const out = this.run(data);
		if (out instanceof OmpErrors) throw new TraversalError(out);
		return out;
	},

	toJsonSchema(this: InternalType, options?: ToJsonSchemaOptions): Record<string, unknown> {
		const ir =
			options?.io === "output" ? (this.opaqueOutput ? OPAQUE_OUTPUT_IR : (this.stepOut ?? this.ir)) : this.ir;
		const description = options?.description ?? this.ir.desc;
		if (description === undefined) return irToJsonSchema(ir, options);
		return irToJsonSchema(ir, { ...options, description });
	},
};

View on GitHub (pinned to 9690622007)

Solutions

1. Inspect `error.summary` / the aggregated OmpErrors for each failed path and fix the data.
2. Use `T.allows(data)` or `const r = T.run(data)` for non-throwing checks first.
3. Update the schema or the data so they agree; for morphs, ensure the input shape matches the morph's input type.

Example fix

// before
T.assert(data); // throws TraversalError on bad data

// after
const result = T.run(data);
if (result instanceof OmpErrors) {
  console.error(result.summary);
} else {
  // result is valid
}

// pre-validate without throwing
if (!T.allows(data)) {
  const r = T.run(data);
  // inspect r (OmpErrors) before calling assert
}

try {
  T.assert(data);
} catch (e) {
  if (e instanceof TraversalError) {
    // e holds aggregated OmpErrors; report per-path problems
  } else throw e;
}

When it happens

Trigger: Calling `T.assert(data)` where data fails any validation constraint — wrong primitive type, missing required prop, failed morph/pipe, out-of-bounds number, etc.

Common situations: Validating external input (HTTP bodies, CLI args, config) at runtime; asserting a value whose shape drifted after a schema change; test assertions on fixture data.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Unsupported language '{value}'. Supported: {}
• Unable to infer language from file extension: {}. Specify `l
• Invalid pattern: {err}
• Failed to load tree-sitter language: {err}
• err.to_string() (invalid glob pattern)

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/795d60852c8a0706. Report an issue: GitHub.