blank strings will be treated the same as nil for filters other than …

…string and symbol

CHANGELOG.md

@@ -6,6 +6,8 @@
 - drop support for Rails < 5.0
 - [#398][] - Predicate methods have been removed.
   ([how to upgrade](#predicate-methods))
+- [#412][] - Filters will now treat blank string values as `nil`
+  (except `string` and `symbol`). ([how to upgrade](#blank-values-treated-as-nil-for-filters))
 - [#392][] - Integer parsing now defaults the base to 10.
   ([how to upgrade](#integer-parsing-base-now-10))
 - The `inputs` method now returns an `ActiveInteraction::Input` instead of a
@@ -63,6 +65,45 @@ class Example < ActiveInteraction::Base
 end
 ```
 
+## Blank Values Treated As `nil` For Filters
+
+In an effort to improve form support, strings that are `blank?` will
+be converted into `nil` for all filters except `string` and `symbol`.
+Previously, blank strings would have cased `:invalid_type` errors but
+they'll now cause a `:missing` error which should be more form
+friendly. If the filter has a default, the blank string will cause
+the default to be used.
+
+```ruby
+class Example < ActiveInteraction::Base
+  integer :i
+  boolean :b, default: false
+
+  def execute
+    [i, b]
+  end
+end
+
+# v3.8
+Example.run(i: '', b: '').errors.details
+=> {:i=>[{:error=>:invalid_type, :type=>"integer"}], :b=>[{:error=>:invalid_type, :type=>"boolean"}]}
+
+# v4.0
+Example.run(i: '', b: '').errors.details
+=> {:i=>[{:error=>:missing}]}
+
+# v3.8
+Example.run(i: 0, b: '').errors.details
+=> {:b=>[{:error=>:invalid_type, :type=>"boolean"}]}
+
+# v4.0
+Example.run(i: 0, b: '').errors.details
+=> {}
+
+Example.run(i: 0, b: '').result
+=> [0, false] # the default is used for `:b`
+```
+
 ### Integer Parsing Base Now 10
 
 Integers are parsed using `Integer`. By default this meant that when

README.md

@@ -267,7 +267,7 @@ end
 
 Boolean filters convert the strings `"1"`, `"true"`, and `"on"`
 (case-insensitive) into `true`. They also convert `"0"`, `"false"`, and `"off"`
-into `false`.
+into `false`. Blank strings will be treated as `nil`.
 
 ``` rb
 class BooleanInteraction < ActiveInteraction::Base
@@ -565,9 +565,10 @@ SymbolInteraction.run!(method: :object_id)
 ### Dates and times
 
 Filters that work with dates and times behave similarly. By default, they all
-convert strings into their expected data types using `.parse`. If you give the
-`format` option, they will instead convert strings using `.strptime`. Note that
-formats won't work with `DateTime` and `Time` filters if a time zone is set.
+convert strings into their expected data types using `.parse`. Blank strings
+will be treated as `nil`. If you give the `format` option, they will instead
+convert strings using `.strptime`. Note that formats won't work with `DateTime`
+and `Time` filters if a time zone is set.
 
 #### Date
 
@@ -641,7 +642,8 @@ time :start,
 ### Numbers
 
 All numeric filters accept numeric input. They will also convert strings using
-the appropriate method from `Kernel` (like `.Float`).
+the appropriate method from `Kernel` (like `.Float`). Blank strings will be
+treated as `nil`.
 
 #### Decimal
 

lib/active_interaction/filters/abstract_date_time_filter.rb

@@ -26,7 +26,8 @@ def matches?(value)
 
     def convert(value)
       if value.respond_to?(:to_str)
-        convert_string(value.to_str)
+        value = value.to_str
+        value.blank? ? send(__method__, nil) : convert_string(value)
       elsif value.is_a?(GroupedInput)
         convert_grouped_input(value)
       else

lib/active_interaction/filters/abstract_numeric_filter.rb

@@ -25,7 +25,8 @@ def convert(value)
       elsif value.respond_to?(:to_int)
         safe_converter(value.to_int)
       elsif value.respond_to?(:to_str)
-        safe_converter(value.to_str)
+        value = value.to_str
+        value.blank? ? send(__method__, nil) : safe_converter(value)
       else
         super
       end

lib/active_interaction/filters/boolean_filter.rb

@@ -31,6 +31,11 @@ def matches?(value)
     end
 
     def convert(value)
+      if value.respond_to?(:to_str)
+        value = value.to_str
+        value = nil if value.blank?
+      end
+
       case value
       when /\A(?:0|false|off)\z/i
         false

spec/active_interaction/filters/boolean_filter_spec.rb

@@ -48,6 +48,34 @@ def to_str
         end
       end
     end
+
+    context 'with a blank String' do
+      let(:value) do
+        Class.new do
+          def to_str
+            ' '
+          end
+        end.new
+      end
+
+      context 'optional' do
+        include_context 'optional'
+
+        it 'returns the default' do
+          expect(filter.cast(value, nil)).to eql options[:default]
+        end
+      end
+
+      context 'required' do
+        include_context 'required'
+
+        it 'raises an error' do
+          expect do
+            filter.cast(value, nil)
+          end.to raise_error ActiveInteraction::MissingValueError
+        end
+      end
+    end
   end
 
   describe '#database_column_type' do

spec/active_interaction/filters/date_filter_spec.rb

@@ -75,6 +75,34 @@ def to_str
       end
     end
 
+    context 'with a blank String' do
+      let(:value) do
+        Class.new do
+          def to_str
+            ' '
+          end
+        end.new
+      end
+
+      context 'optional' do
+        include_context 'optional'
+
+        it 'returns the default' do
+          expect(result).to eql options[:default]
+        end
+      end
+
+      context 'required' do
+        include_context 'required'
+
+        it 'raises an error' do
+          expect do
+            result
+          end.to raise_error ActiveInteraction::MissingValueError
+        end
+      end
+    end
+
     context 'with a GroupedInput' do
       let(:year) { 2012 }
       let(:month) { 1 }

spec/active_interaction/filters/date_time_filter_spec.rb

@@ -75,6 +75,34 @@ def to_str
       end
     end
 
+    context 'with a blank String' do
+      let(:value) do
+        Class.new do
+          def to_str
+            ' '
+          end
+        end.new
+      end
+
+      context 'optional' do
+        include_context 'optional'
+
+        it 'returns the default' do
+          expect(result).to eql options[:default]
+        end
+      end
+
+      context 'required' do
+        include_context 'required'
+
+        it 'raises an error' do
+          expect do
+            result
+          end.to raise_error ActiveInteraction::MissingValueError
+        end
+      end
+    end
+
     context 'with a GroupedInput' do
       let(:year) { 2012 }
       let(:month) { 1 }

spec/active_interaction/filters/decimal_filter_spec.rb

@@ -86,6 +86,34 @@ def to_str
         expect(result).to eql BigDecimal(value)
       end
     end
+
+    context 'with a blank String' do
+      let(:value) do
+        Class.new do
+          def to_str
+            ' '
+          end
+        end.new
+      end
+
+      context 'optional' do
+        include_context 'optional'
+
+        it 'returns the default' do
+          expect(result).to eql options[:default]
+        end
+      end
+
+      context 'required' do
+        include_context 'required'
+
+        it 'raises an error' do
+          expect do
+            result
+          end.to raise_error ActiveInteraction::MissingValueError
+        end
+      end
+    end
   end
 
   describe '#database_column_type' do

spec/active_interaction/filters/float_filter_spec.rb

@@ -70,6 +70,34 @@ def to_str
         expect(result).to eql Float(value.to_str)
       end
     end
+
+    context 'with a blank String' do
+      let(:value) do
+        Class.new do
+          def to_str
+            ' '
+          end
+        end.new
+      end
+
+      context 'optional' do
+        include_context 'optional'
+
+        it 'returns the default' do
+          expect(result).to eql options[:default]
+        end
+      end
+
+      context 'required' do
+        include_context 'required'
+
+        it 'raises an error' do
+          expect do
+            result
+          end.to raise_error ActiveInteraction::MissingValueError
+        end
+      end
+    end
   end
 
   describe '#database_column_type' do

spec/active_interaction/filters/integer_filter_spec.rb

@@ -56,6 +56,34 @@ def to_str
       end
     end
 
+    context 'with a blank String' do
+      let(:value) do
+        Class.new do
+          def to_str
+            ' '
+          end
+        end.new
+      end
+
+      context 'optional' do
+        include_context 'optional'
+
+        it 'returns the default' do
+          expect(result).to eql options[:default]
+        end
+      end
+
+      context 'required' do
+        include_context 'required'
+
+        it 'raises an error' do
+          expect do
+            result
+          end.to raise_error ActiveInteraction::MissingValueError
+        end
+      end
+    end
+
     it 'supports different bases' do
       expect(described_class.new(name, base: 8).cast('071', nil)).to eql 57
       expect do

spec/active_interaction/filters/time_filter_spec.rb

@@ -97,6 +97,34 @@ def to_str
       end
     end
 
+    context 'with a blank String' do
+      let(:value) do
+        Class.new do
+          def to_str
+            ' '
+          end
+        end.new
+      end
+
+      context 'optional' do
+        include_context 'optional'
+
+        it 'returns the default' do
+          expect(result).to eql options[:default]
+        end
+      end
+
+      context 'required' do
+        include_context 'required'
+
+        it 'raises an error' do
+          expect do
+            result
+          end.to raise_error ActiveInteraction::MissingValueError
+        end
+      end
+    end
+
     context 'with an Integer' do
       let(:value) { rand(1 << 16) }