Stop on first failure

System Details

• FluentValidation version: 8.4.0

Issue Description

Is it possible to stop validation on first failure? I could not find the answer in github and also stack overflow. I hope that someone can help me.

Here is the current code I find in github

public abstract class AbstractValidator<T> : IValidator<T>, IEnumerable<IValidationRule> {
   internal TrackingCollection<IValidationRule> Rules { get; } = new TrackingCollection<IValidationRule>();
   public async virtual Task<ValidationResult> ValidateAsync(ValidationContext<T> context, CancellationToken cancellation = new CancellationToken()) {
	context.Guard("Cannot pass null to Validate", nameof(context));
	context.RootContextData["__FV_IsAsyncExecution"] = true;
	var result = new ValidationResult();
	bool shouldContinue = PreValidate(context, result);
	if (!shouldContinue) {
		return result;
	}
	EnsureInstanceNotNull(context.InstanceToValidate);
	foreach (var rule in Rules) {
		cancellation.ThrowIfCancellationRequested();
		var failures = await rule.ValidateAsync(context, cancellation);
		foreach (var failure in failures.Where(f => f != null)) {
			result.Errors.Add(failure);
		}
	}
	SetExecutedRulesets(result, context);
	return result;
}

In order to tackle my problem, I need to override our current ValidateAsync like this

public override async Task<ValidationResult> ValidateAsync(ValidationContext<T> context, CancellationToken cancellation = default(CancellationToken))
        {
            context.RootContextData["__FV_IsAsyncExecution"] = true;
            var result = new ValidationResult();
            var rules = (IEnumerable<IValidationRule>)this.GetType().GetProperty("Rules", BindingFlags.Instance | BindingFlags.GetProperty | BindingFlags.NonPublic).GetValue(this);
            foreach (var rule in rules)
            {
                cancellation.ThrowIfCancellationRequested();
                var failures = await rule.ValidateAsync(context, cancellation);
                foreach (var failure in failures.Where(f => f != null))
                {
                    result.Errors.Add(failure);
                }
                // stop on first error
                if (result.Errors.Any())
                {
                    return result;
                }
            }
            return result;
        }

but it is too ugly imo.

Thanks,

[lust4life]

@minhtd1981 maybe you can set some context when there is an error occur in OnFailure, then check it to decide whether execution needs to continue in ‘Selector.CanExecute’ like what RuleSets do. But this should be only used in general cases, when in advanced case , DependentRules should be used.

but if @JeremySkinner can add some options for this case like what you do (skip other rules when first rule has some errors), that would be nice for case when need fast failed check.

[minhtd1981]

Hi @JeremySkinner,

If there is no other way around, I will stick with DependentRules.

FYI. base.Validate(context) will validate all other property rules and that causes database hits.

I was not aware that Validator implements IEnumerable<IValidationRule> that is really cool.

Thanks a lot,