ent/ent · error · ValidationError

{{ $pkg }}: validator failed for field "{{ $.Name }}.{{ $f.N

Error message

{{ $pkg }}: validator failed for field "{{ $.Name }}.{{ $f.Name }}": %w

What it means

This error is generated in the Create builder's validation step. Before saving, ent runs the field's validator functions, enum checks, or a Validate() method on custom Go types. If any fails, it wraps the validator's error in a ValidationError naming the schema type and field. It means the value being inserted violates the schema's field constraints.

Source

Thrown at entc/gen/template/builder/create.tmpl:123

			{{- if $n }}
				{{- $partially := ne $n (len $.Config.Storage.Dialects) }}
				{{- if $partially }}
					switch {{ $receiver }}.driver.Dialect() {
					case {{ join $dialects ", " }}:
				{{- end }}
					if _, ok := {{ $mutation }}.{{ $f.MutationGet }}(); !ok {
						return &ValidationError{Name: "{{ $f.Name }}", err: errors.New(`{{ $pkg }}: missing required field "{{ $.Name }}.{{ $f.Name }}"`)}
					}
				{{- if $partially }}
					}
				{{- end }}
			{{- end }}
		{{- end }}
		{{- $isValidator := and ($f.HasGoType) ($f.Type.Validator) }}
		{{- with or $f.Validators $f.IsEnum $isValidator }}
			if v, ok := {{ $mutation }}.{{ $f.MutationGet }}(); ok {
				if err := {{ if or $f.Validators $f.IsEnum }}{{ $.Package }}.{{ $f.Validator }}({{ $f.BasicType "v" }}){{ else }}v.Validate(){{ end }}; err != nil {
					return &ValidationError{Name: "{{ $f.Name }}", err: fmt.Errorf(`{{ $pkg }}: validator failed for field "{{ $.Name }}.{{ $f.Name }}": %w`, err)}
				}
			}
		{{- end }}
	{{- end }}
	{{- range $e := $.EdgesWithID }}
		{{- if not $e.Optional }}
			if len({{ $mutation }}.{{ $e.StructField }}IDs()) == 0 {
				return &ValidationError{Name: "{{ $e.Name }}", err: errors.New(`{{ $pkg }}: missing required edge "{{ $.Name }}.{{ $e.Name }}"`)}
			}
		{{- end }}
	{{- end }}
	return nil
}

{{ with extend $ "Receiver" $receiver "Builder" $builder }}
	{{ $tmpl := printf "dialect/%s/create" $.Storage }}
	{{ xtemplate $tmpl . }}
{{ end }}

View on GitHub (pinned to 69d5d4deb1)

Solutions

  1. Inspect the wrapped validator error to see which rule failed.
  2. Adjust the value passed to the Set<Field> call so it passes the validator/enum.
  3. If the validator is too strict, update the field validator in the schema and run ent generate.
  4. Use mutation.Validate() or the builder's check before Save to catch it early.

Example fix

// before
client.User.Create().SetEmail("not-an-email").Save(ctx)
// after
if err := client.User.Create().SetEmail("user@example.com").Save(ctx); err != nil {
    var verr *ent.ValidationError
    if errors.As(err, &verr) { /* handle field: verr.Name */ }
}
Defensive patterns

Strategy: try-catch

Validate before calling

// Validate before Save
if err := builder.Validate(); err != nil {
    var verr *ent.ValidationError
    if errors.As(err, &verr) { /* inspect verr.Name */ }
}

Type guard

func IsEntValidationError(err error) (field string, ok bool) {
    var verr *ent.ValidationError
    if errors.As(err, &verr) {
        return verr.Name, true
    }
    return "", false
}

Try / catch

if _, err := client.User.Create().SetAge(v).Save(ctx); err != nil {
    var verr *ent.ValidationError
    if errors.As(err, &verr) && verr.Name == "age" {
        return fmt.Errorf("invalid age: %w", err)
    }
    return err
}

Prevention

When it happens

Trigger: Calling client.User.Create().SetAge(200)...Save(ctx) where SetAge's value fails the field's validator (e.g. positive int check), violates an enum constraint, or a custom Go-type field's Validate() method returns an error.

Common situations: Inserting values outside enum lists; custom types with Validate() rejecting edge cases (empty strings, negative numbers); validators updated in the schema after data was already produced against older rules.

Related errors

AI-assisted analysis of ent/ent@69d5d4deb1 (2026-09-03). Data as JSON: /api/errors/4176af5aaa802946. Report an issue: GitHub.