validation_hints

Proactive validation hints derived from model validators — complementary to Rails errors (which react after valid? fails).

Requirements: Ruby >= 4.0, Rails / Active Record 7.2.x (>= 7.2.3.1, < 7.3). Used by inline_forms 7.x for label tooltips on validated fields.

Install

# Gemfile
gem "validation_hints", "~> 7.13"

Rails apps load the gem via ValidationHints::Railtie (no manual require).

inline_forms

Generated apps include validation_hints automatically. The engine patches load order so hints work when rails/all loads before Bundler. Tooltips use has_validations_for?, hints.full_messages_for, and Tippy.js in inline_forms 7.9.x — see inline_forms CHANGELOG.md.

Example

class Person < ApplicationRecord
  validates :name, presence: true
  validates :password, length: { within: 1...5 }
end

Person.new.hints[:name]      # => ["can't be blank"]
Person.new.hints[:password]  # => ["must be between 1 and 4 characters"]

Person.new.hints.full_messages_for(:name)  # => ["Name can't be blank"]
Person.new.has_validations_for?(:name)     # => true

API (stable)

Method	Description
model.hints	ActiveModel::Hints for the instance
hints[:attribute]	Short hint strings for an attribute
hints.full_messages_for(attr)	Attribute label + hint (used by inline_forms tooltips)
has_validations? / has_validations_for?(attr)	Whether to show hint UI

I18n

Default copy lives in the gem at lib/validation_hints/locale/en.yml under the hints namespace.

Lookup order mirrors Rails errors, but uses hints instead of errors:

1. activerecord.hints.models.<model>.attributes.<attr>.<type>
2. activerecord.hints.models.<model>.<type>
3. activerecord.hints.messages.<type>
4. activemodel.hints.messages.<type>
5. hints.attributes.<attr>.<type>
6. hints.messages.<type>

Full messages (full_messages_for) use hints.format with the same scoping (activerecord.hints.format, activemodel.hints.format, hints.format).

App overrides

Add a locale file, e.g. config/locales/validation_hints.en.yml:

en:
  activerecord:
    hints:
      format: "%{attribute}: %{message}"
      messages:
        presence: "is required"
      models:
        apartment:
          attributes:
            name:
              presence: "enter a name for this apartment"

Per-attribute overrides without a model block:

en:
  hints:
    attributes:
      name:
        presence: "is required"

Attribute labels in full messages come from the normal Rails path (activerecord.attributes.<model>.<attr>), same as errors.

Conditional validators

:if, :unless, and :on are not evaluated when building hints. Hints describe the static validation rules declared on the model, not whether they would run for the current record state. Use errors (after valid?) when you need conditional feedback.

Custom validators

validates :attr, my_validator: true (EachValidator)

The hint type is derived from the validator class name (MyValidator → my). Add copy under hints.messages.my or per-model/per-attribute keys in the lookup chain.

validates_with MyValidator (class validator)

Only EachValidator-style validators (declared per attribute) produce hints automatically. Class-level ActiveModel::Validator implementations are not introspectable for attribute lists — prefer validates :attr, … or an EachValidator subclass when you need hint tooltips.

Format validators

validates :attr, format: { with: /…/ } emits the default hints.messages.format copy (“must match the required format”). Override globally, per model, or per attribute via the I18n lookup chain; or set message: on the validator.

en:
  activerecord:
    hints:
      models:
        person:
          attributes:
            code:
              format: "must be numeric"

Security

Runtime dependency is Active Record 7.2.x only (no Action View / Active Storage in the gem).

Dev dependencies were slimmed from full rails to activerecord + activemodel to reduce audit noise. Run:

bundler-audit check --update

Rails 7.2.x advisories: run bundle exec bundler-audit in your app; bump patch releases as needed.

Tests

From the gem root:

bundle install
bundle exec rake test

Runs Minitest against an in-memory SQLite Active Record 7.2 app (test/test_helper.rb).

History

See CHANGELOG.md.