Merge pull request rails#43495 from DRBragg/drbragg/except_option_for_validations

Add `:except_on` option for validations

Author: byroot

activemodel/CHANGELOG.md

@@ -1,3 +1,18 @@
+*   Add `:except_on` option for validations. Grants the ability to _skip_ validations in specified contexts.
+
+    ```ruby
+    class User < ApplicationRecord
+        #...
+        validates :birthday, presence: { except_on: :admin }
+        #...
+    end
+
+    user = User.new(attributes except birthday)
+    user.save(context: :admin)
+    ```
+
+    *Drew Bragg*
+
 ## Rails 8.0.0.beta1 (September 26, 2024) ##
 
 *   Make `ActiveModel::Serialization#read_attribute_for_serialization` public

activemodel/lib/active_model/validations.rb

@@ -69,6 +69,11 @@ module ClassMethods
       #   or an array of symbols. (e.g. <tt>on: :create</tt> or
       #   <tt>on: :custom_validation_context</tt> or
       #   <tt>on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:except_on</tt> - Specifies the contexts where this validation is not active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>except: :create</tt> or
+      #   <tt>except_on: :custom_validation_context</tt> or
+      #   <tt>except_on: [:create, :custom_validation_context]</tt>)
       # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+.
       # * <tt>:allow_blank</tt> - Skip validation if attribute is blank.
       # * <tt>:if</tt> - Specifies a method, proc, or string to call to determine
@@ -84,7 +89,7 @@ def validates_each(*attr_names, &block)
         validates_with BlockValidator, _merge_attributes(attr_names), &block
       end
 
-      VALID_OPTIONS_FOR_VALIDATE = [:on, :if, :unless, :prepend].freeze # :nodoc:
+      VALID_OPTIONS_FOR_VALIDATE = [:on, :if, :unless, :prepend, :except_on].freeze # :nodoc:
 
       # Adds a validation method or block to the class. This is useful when
       # overriding the +validate+ instance method becomes too unwieldy and
@@ -135,7 +140,12 @@ def validates_each(*attr_names, &block)
       #   or an array of symbols. (e.g. <tt>on: :create</tt> or
       #   <tt>on: :custom_validation_context</tt> or
       #   <tt>on: [:create, :custom_validation_context]</tt>)
-      # * <tt>:if</tt> - Specifies a method, proc, or string to call to determine
+      # * <tt>:except_on</tt> - Specifies the contexts where this validation is not active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>except: :create</tt> or
+      #   <tt>except_on: :custom_validation_context</tt> or
+      #   <tt>except_on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
       #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
       #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
       #   proc or string should return or evaluate to a +true+ or +false+ value.
@@ -162,6 +172,15 @@ def validate(*args, &block)
           options = options.merge(if: [predicate_for_validation_context(options[:on]), *options[:if]])
         end
 
+        if options.key?(:except_on)
+          options = options.dup
+          options[:except_on] = Array(options[:except_on])
+          options[:unless] = [
+            ->(o) { (options[:except_on] & Array(o.validation_context)).any? },
+            *options[:unless]
+          ]
+        end
+
         set_callback(:validate, *args, options, &block)
       end
 

activemodel/lib/active_model/validations/validates.rb

@@ -78,7 +78,12 @@ module ClassMethods
       #   or an array of symbols. (e.g. <tt>on: :create</tt> or
       #   <tt>on: :custom_validation_context</tt> or
       #   <tt>on: [:create, :custom_validation_context]</tt>)
-      # * <tt>:if</tt> - Specifies a method, proc, or string to call to determine
+      # * <tt>:except_on</tt> - Specifies the contexts where this validation is not active.
+      #   Runs in all validation contexts by default +nil+. You can pass a symbol
+      #   or an array of symbols. (e.g. <tt>except: :create</tt> or
+      #   <tt>except_on: :custom_validation_context</tt> or
+      #   <tt>except_on: [:create, :custom_validation_context]</tt>)
+      # * <tt>:if</tt> - Specifies a method, proc or string to call to determine
       #   if the validation should occur (e.g. <tt>if: :allow_validation</tt>,
       #   or <tt>if: Proc.new { |user| user.signup_step > 2 }</tt>). The method,
       #   proc or string should return or evaluate to a +true+ or +false+ value.
@@ -155,7 +160,7 @@ def validates!(*attributes)
       # When creating custom validators, it might be useful to be able to specify
       # additional default keys. This can be done by overwriting this method.
       def _validates_default_keys
-        [:if, :unless, :on, :allow_blank, :allow_nil, :strict]
+        [:if, :unless, :on, :allow_blank, :allow_nil, :strict, :except_on]
       end
 
       def _parse_validates_options(options)

activemodel/test/cases/validations_test.rb

@@ -170,7 +170,7 @@ def test_invalid_options_to_validate
       # A common mistake -- we meant to call 'validates'
       Topic.validate :title, presence: true
     end
-    message = "Unknown key: :presence. Valid keys are: :on, :if, :unless, :prepend. Perhaps you meant to call `validates` instead of `validate`?"
+    message = "Unknown key: :presence. Valid keys are: :on, :if, :unless, :prepend, :except_on. Perhaps you meant to call `validates` instead of `validate`?"
     assert_equal message, error.message
   end
 
@@ -462,4 +462,29 @@ def test_frozen_models_can_be_validated
     assert_predicate person, :frozen?
     assert_not person.valid?
   end
+
+  def test_validate_with_except_on
+    Topic.validates :title, presence: true, except_on: :custom_context
+
+    topic = Topic.new
+    topic.validate
+
+    assert_equal ["can't be blank"], topic.errors[:title]
+
+    assert topic.validate(:custom_context)
+  end
+
+  def test_validations_some_with_except
+    Topic.validates :title, presence: { except_on: :custom_context }, length: { maximum: 10 }
+
+    assert_raise(ActiveModel::ValidationError) do
+      Topic.new.validate!
+    end
+
+    assert_raise(ActiveModel::ValidationError) do
+      Topic.new(title: "A" * 11).validate!(:custom_context)
+    end
+
+    assert Topic.new.validate!(:custom_context)
+  end
 end