Changed gem dependencies from install-time in gemspec to runtime when…

… each of the generators is loaded. This allows use of github gems (i.e. relevance-rcov instead of rcov) and also allows you to install only the gems for the metrics you plan on using.

lib/base/generator.rb

@@ -33,6 +33,7 @@ class Generator
     attr_reader :report, :template
 
     def initialize(options={})
+      self.class.verify_dependencies!
       create_metric_dir_if_missing
       create_output_dir_if_missing
     end
@@ -119,6 +120,11 @@ def generate_report
     def round_to_tenths(decimal)
       (decimal * 10).round / 10.0 
     end
+
+    # Allows subclasses to check for required gems
+    def self.verify_dependencies!
+      true
+    end
 
     def emit #:nodoc:
       raise <<-EOF

lib/generators/flay.rb

@@ -3,6 +3,11 @@ module MetricFu
 
   class Flay < Generator
 
+    def self.verify_dependencies!
+      `flay --help`
+      raise 'sudo gem install flay # if you want the flay tasks' unless $?.success?
+    end
+
     def emit
       files_to_flay = MetricFu.flay[:dirs_to_flay].map{|dir| Dir[File.join(dir, "**/*.rb")] }
       @output = `flay #{files_to_flay.join(" ")}`

lib/generators/flog.rb

@@ -3,6 +3,11 @@ module MetricFu
   class Flog < Generator
     attr_reader :pages
 
+    def self.verify_dependencies!
+      `flog --help`
+      raise 'sudo gem install flog # if you want the flog tasks' unless $?.success?
+    end
+
     SCORE_FORMAT = "%0.2f"
     METHOD_LINE_REGEX = /(\d+\.\d+):\s+([A-Za-z:]+#.*)/
     OPERATOR_LINE_REGEX = /\s*(\d+\.\d+):\s(.*)$/

lib/generators/rcov.rb

@@ -5,6 +5,16 @@ module MetricFu
   class Rcov < Generator
     NEW_FILE_MARKER =  ("=" * 80) + "\n"
 
+    def self.verify_dependencies!
+      `flay --help`
+      unless $?.success?
+        if RUBY_PLATFORM =~ /java/
+          raise 'running in jruby - rcov tasks not available'
+        else
+          raise 'sudo gem install rcov # if you want the rcov tasks'
+        end
+      end
+    end
 
     class Line
       attr_accessor :content, :was_run

lib/generators/reek.rb

@@ -3,6 +3,11 @@ module MetricFu
   class Reek < Generator
     REEK_REGEX = /^(\S+) (.*) \((.*)\)$/
 
+    def self.verify_dependencies!
+      `reek --help`
+      raise 'sudo gem install reek # if you want the reek tasks' unless $?.success?
+    end
+
     def emit
       files_to_reek = MetricFu.reek[:dirs_to_reek].map{|dir| Dir[File.join(dir, "**/*.rb")] }
       @output = `reek #{files_to_reek.join(" ")}`

lib/generators/roodi.rb

@@ -1,5 +1,12 @@
 module MetricFu
   class Roodi < Generator
+
+    def self.verify_dependencies!
+      `roodi --help`
+      raise 'sudo gem install roodi # if you want the roodi tasks' unless $?.success?
+    end
+
+
     def emit
       files_to_analyze = MetricFu.roodi[:dirs_to_roodi].map{|dir| Dir[File.join(dir, "**/*.rb")] }
       @output = `roodi #{files_to_analyze.join(" ")}`

lib/generators/saikuro.rb

@@ -2,11 +2,12 @@ module MetricFu
 
 class Saikuro < Generator
 
+  def self.verify_dependencies!
+    `ruby "#{saikuro}" --help`
+    raise "Please check #{saikuro} is a valid installation of saikuro" unless $?.success?
+  end
 
   def emit
-    relative_path = [File.dirname(__FILE__), '..', '..',
-                     'vendor', 'saikuro', 'saikuro.rb']
-    saikuro = File.expand_path(File.join(relative_path))
 
     format_directories
 
@@ -81,6 +82,14 @@ def saikuro_results
 
   private
 
+  def self.saikuro
+    relative_path = [File.dirname(__FILE__), '..', '..',
+                     'vendor', 'saikuro', 'saikuro.rb']
+    File.expand_path(File.join(relative_path))
+  end
+  def saikuro
+    self.class.saikuro
+  end
 
 end
 

metric_fu.gemspec

@@ -24,10 +24,5 @@ Gem::Specification.new do |s|
   s.has_rdoc = true
   s.rdoc_options = ["--main", "README"]
   s.extra_rdoc_files = ["HISTORY", "Manifest.txt", "README"]
-  s.add_dependency("flay", [">= 1.2.1"])  
-  s.add_dependency("flog", [">= 2.1.0"])
-  s.add_dependency("rcov", ["> 0.8.1"])
-  s.add_dependency("reek", [">= 1.0.0"])
-  s.add_dependency("roodi", [">= 1.3.5"])
   s.add_dependency("chronic", [">= 0.2.3"])
 end

spec/base/generator_spec.rb

@@ -154,6 +154,28 @@ def to_h
       @concrete_class.should_receive(:to_h)
       @concrete_class.generate_report
     end
+
+    it "should raise error if the concrete class is missing a required dependency" do
+      concrete_class_with_missing_gem = Class.new(MetricFu::Generator) do
+        def self.verify_dependencies!
+          raise 'gem install something # if you want these tasks'
+        end
+      end
+      lambda { concrete_class_with_missing_gem.generate_report }.should raise_error("gem install something # if you want these tasks")
+    end
 
   end
+
+  describe "instantiation" do
+    it "should fail is dependencies not verified" do
+      ConcreteClass.should_receive(:verify_dependencies!).and_raise("Missing a required gem. Please 'gem install something'")      
+      lambda { ConcreteClass.new() }.should raise_error("Missing a required gem. Please 'gem install something'")
+    end
+
+    it "should succeed when dependencies verified" do
+      ConcreteClass.should_receive(:verify_dependencies!).and_return(true)
+      ConcreteClass.new()
+    end
+  end
+
 end

spec/generators/flay_spec.rb

@@ -1,6 +1,9 @@
 require File.dirname(__FILE__) + '/../spec_helper.rb'
 
 describe Flay do 
+  before :each do
+    MetricFu::Flay.stub!(:verify_dependencies!).and_return(true)
+  end
   describe "emit method" do
     before :each do
       MetricFu::Configuration.run {|config| config.flay = { :dirs_to_flay => ['app', 'lib']  } }

spec/generators/flog_spec.rb

@@ -123,6 +123,7 @@
       1.2: assignment
       1.2: all
     HERE
+    MetricFu::Flog.stub!(:verify_dependencies!).and_return(true)
   end
 
   describe "parse method" do

spec/generators/reek_spec.rb

@@ -3,6 +3,7 @@
 describe Reek do
   describe "analyze method" do
     before :each do
+      MetricFu::Reek.stub!(:verify_dependencies!).and_return(true)
       @lines = <<-HERE
 "app/controllers/activity_reports_controller.rb" -- 4 warnings:
 ActivityReportsController#authorize_user calls current_user.primary_site_ids multiple times (Duplication)