Added a minlength validation on first attempt? Wooo - wish I could put bangs in commit messages *bang*

.gitignore

@@ -2,3 +2,4 @@
 pkg/
 rdoc/
 gemfiles/*.lock
+/.idea/

lib/simple_form/components.rb

@@ -15,6 +15,7 @@ module SimpleForm
     autoload :Labels
     autoload :MinMax
     autoload :Maxlength
+    autoload :Minlength
     autoload :Pattern
     autoload :Placeholders
     autoload :Readonly

lib/simple_form/components/minlength.rb

@@ -0,0 +1,34 @@
+module SimpleForm
+  module Components
+    # Needs to be enabled in order to do automatic lookups.
+    module Minlength
+      def minlength(wrapper_options = nil)
+        input_html_options[:minlength] ||= minimum_length_from_validation || limit
+        nil
+      end
+
+      private
+
+      def minimum_length_from_validation
+        minlength = options[:minlength]
+        if minlength.is_a?(String) || minlength.is_a?(Integer)
+          minlength
+        else
+          length_validator = find_length_validator
+
+          if length_validator && !has_tokenizer?(length_validator)
+            length_validator.options[:is] || length_validator.options[:minimum]
+          end
+        end
+      end
+
+      def find_length_validator
+        find_validator(:length)
+      end
+
+      def has_tokenizer?(length_validator)
+        length_validator.options[:tokenizer]
+      end
+    end
+  end
+end

lib/simple_form/inputs/base.rb

@@ -21,6 +21,7 @@ module SimpleForm
       include SimpleForm::Components::HTML5
       include SimpleForm::Components::LabelInput
       include SimpleForm::Components::Maxlength
+      include SimpleForm::Components::Minlength
       include SimpleForm::Components::MinMax
       include SimpleForm::Components::Pattern
       include SimpleForm::Components::Placeholders
@@ -50,7 +51,7 @@ module SimpleForm
       enable :hint
 
       # Usually disabled, needs to be enabled explicitly passing true as option.
-      disable :maxlength, :placeholder, :pattern, :min_max
+      disable :maxlength, :minlength, :placeholder, :pattern, :min_max
 
       def initialize(builder, attribute_name, column, input_type, options = {})
         super

lib/simple_form/inputs/password_input.rb

@@ -1,7 +1,7 @@
 module SimpleForm
   module Inputs
     class PasswordInput < Base
-      enable :placeholder, :maxlength
+      enable :placeholder, :maxlength, :minlength
 
       def input(wrapper_options = nil)
         merged_input_options = merge_wrapper_options(input_html_options, wrapper_options)

lib/simple_form/inputs/string_input.rb

@@ -1,7 +1,7 @@
 module SimpleForm
   module Inputs
     class StringInput < Base
-      enable :placeholder, :maxlength, :pattern
+      enable :placeholder, :maxlength, :minlength, :pattern
 
       def input(wrapper_options = nil)
         unless string?

lib/simple_form/inputs/text_input.rb

@@ -1,7 +1,7 @@
 module SimpleForm
   module Inputs
     class TextInput < Base
-      enable :placeholder, :maxlength
+      enable :placeholder, :maxlength, :minlength
 
       def input(wrapper_options = nil)
         merged_input_options = merge_wrapper_options(input_html_options, wrapper_options)

test/form_builder/input_field_test.rb

@@ -151,6 +151,14 @@ class InputFieldTest < ActionView::TestCase
     end
   end
 
+  test 'build input_field without minlength component use the minlength string' do
+    swap_wrapper :default, custom_wrapper_with_html5_components do
+      with_input_field_for @user, :name, minlength: 5
+
+      assert_select 'input[minlength="5"]'
+    end
+  end
+
   test 'build input_field without readonly component use the readonly string' do
     swap_wrapper :default, custom_wrapper_with_html5_components do
       with_input_field_for @user, :name, readonly: true