Allow to suppress automatic creation of --no-boolean flags

lib/thor.rb

@@ -151,6 +151,8 @@ def method_options(options = nil)
     # :type     - The type of the argument, can be :string, :hash, :array, :numeric or :boolean.
     # :banner   - String to show on usage notes.
     # :hide     - If you want to hide this option from the help.
+    # :inverse  - false if yo don't want an inverse option of your boolean type, String or Symbol
+    #             if you want to override the inverse option name.
     #
     def method_option(name, options = {})
       scope = if options[:for]

lib/thor/parser/option.rb

@@ -13,6 +13,7 @@ def initialize(name, options = {})
       @group          = options[:group].to_s.capitalize if options[:group]
       @aliases        = Array(options[:aliases])
       @hide           = options[:hide]
+      @inverse        = options[:inverse]
     end
 
     # This parse quick options given as method_options. It makes several
@@ -81,17 +82,7 @@ def human_name
     end
 
     def usage(padding = 0)
-      sample = if banner && !banner.to_s.empty?
-        "#{switch_name}=#{banner}".dup
-      else
-        switch_name
-      end
-
-      sample = "[#{sample}]".dup unless required?
-
-      if boolean?
-        sample << ", [#{dasherize('no-' + human_name)}]" unless (name == "force") || name.start_with?("no-")
-      end
+      sample = [ sample_banner, inverse_sample ].compact.join(", ")
 
       if aliases.empty?
         (" " * padding) << sample
@@ -110,6 +101,26 @@ def #{type}?
 
   protected
 
+    def sample_banner
+      sample_banner = if banner && !banner.to_s.empty?
+                        "#{switch_name}=#{banner}".dup
+                      else
+                        switch_name
+                      end
+      required? ? sample_banner : "[#{sample_banner}]"
+    end
+
+    def inverse_sample
+      return if !boolean? || name =~ /^(force|no-.*)$/
+
+      case @inverse
+      when Symbol, String
+        "[#{dasherize(@inverse.to_s)}]"
+      when nil, true
+        "[#{dasherize('no-' + human_name)}]"
+      end
+    end
+
     def validate!
       raise ArgumentError, "An option cannot be boolean and required." if boolean? && required?
       validate_default_type!

spec/parser/option_spec.rb

@@ -119,6 +119,22 @@ def option(name, options = {})
     expect(option("--foo").switch_name).to eq("--foo")
   end
 
+  it "suppresses the creation of a --no-option when explicitly requested" do
+    expect(option("bar", type: :boolean, :inverse => false).usage).to_not include("[--no-bar]")
+  end
+
+  it "allow to override the inverse option" do
+    expect(option("colorful", type: :boolean, :inverse => :monochromatic).usage).to include("[--monochromatic]")
+  end
+
+  it "creates the inversion flag by default" do
+    expect(option("bar", type: :boolean).usage).to include("[--no-bar]")
+  end
+
+  it "creates the inversion flag when requested" do
+    expect(option("bar", type: :boolean, :inverse => true).usage).to include("[--no-bar]")
+  end
+
   it "returns the human name" do
     expect(option("foo").human_name).to eq("foo")
     expect(option("--foo").human_name).to eq("foo")