theonedev/onedev · error · ValidationException

At least one value needs to be specified

Error message

At least one value needs to be specified

What it means

This ValidationException is thrown by ParamUtils.validateParamValues when the list of value-combinations for a job parameter is empty. BuildSpec job parameters defined with a values provider must specify at least one value combination; an empty list means the parameter can never take a value, so validation fails fast. The message is later wrapped by validateParamMatrix with the offending param name.

Source

Thrown at server-core/src/main/java/io/onedev/server/buildspec/param/ParamUtils.java:34

import org.apache.commons.lang.SerializationUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.jspecify.annotations.Nullable;
import javax.validation.ValidationException;
import java.io.Serializable;
import java.util.*;
import java.util.stream.Collectors;

public class ParamUtils {
	
	private static final Logger logger = LoggerFactory.getLogger(ParamInstances.class);
	
	private static final String PARAM_BEAN_CLASS_NAME_PREFIX = "BuildParamBean";
	
	public static void validateParamValues(List<List<String>> values) {
		if (values.isEmpty())
			throw new ValidationException("At least one value needs to be specified");
		Set<List<String>> encountered = new HashSet<>();
		for (List<String> value: values) {
			if (encountered.contains(value)) 
				throw new ValidationException("Duplicate values not allowed");
			else 
				encountered.add(value);
		}
	}
	
	private static void validateParamMatrix(List<ParamSpec> paramSpecs, Map<String, List<List<String>>> paramMatrix) {
		Map<String, ParamSpec> paramSpecMap = ParamUtils.getParamSpecMap(paramSpecs);
		validateParamNames(paramSpecMap.keySet(), paramMatrix.keySet());
		for (Map.Entry<String, List<List<String>>> entry: paramMatrix.entrySet()) {
			if (entry.getValue() != null) {
				try {
					validateParamValues(entry.getValue());
				} catch (ValidationException e) {
					String errorMessage = String.format("Error validating param values (param: %s, error message: %s)",

View on GitHub (pinned to d44925c47c)

Solutions

  1. Add at least one value (row) to the parameter's specified values list
  2. If the parameter should not constrain values, remove the values provider / parameter instead of leaving it empty
  3. Check YAML indentation so values are actually parsed into the list rather than dropped

Example fix

// before
params:
  - name: version
    values:
// after
params:
  - name: version
    values:
      - "1.0"
      - "2.0"
Defensive patterns

Strategy: validation

Validate before calling

if (values == null || values.isEmpty())
    throw new IllegalArgumentException("param values must contain at least one combination");

Try / catch

try { ParamUtils.validateParamValues(values); } catch (ValidationException e) { /* show 'add at least one value' UI hint */ }

Prevention

When it happens

Trigger: Calling ParamUtils.validateParamValues with an empty List<List<String>>, typically via validateParamMatrix when a BuildParam's SpecifiedValues.getValues() returns an empty list for a parameter.

Common situations: A developer defines a job parameter in .onedev-buildspec.yml with `values:` left empty or removes all values from the list; UI form saved with no rows; programmatic BuildSpec construction passing new ArrayList<>() as values.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

AI-assisted analysis of theonedev/onedev@d44925c47c (2026-09-06). Data as JSON: /api/errors/f2e75fd214958ead. Report an issue: GitHub.