Merge branch 'add_conflicts' of https://github.com/take-cheeze/mruby into take-cheeze-add_conflicts

tasks/mrbgem_spec.rake

@@ -32,7 +32,7 @@ module MRuby
       attr_accessor :bins
 
       attr_accessor :requirements
-      attr_reader :dependencies
+      attr_reader :dependencies, :conflicts
 
       attr_accessor :export_include_paths
 
@@ -72,7 +72,7 @@ module MRuby
         @bins = []
 
         @requirements = []
-        @dependencies = []
+        @dependencies, @conflicts = [], []
         @export_include_paths = []
         @export_include_paths << "#{dir}/include" if File.directory? "#{dir}/include"
 
@@ -102,6 +102,14 @@ module MRuby
         @dependencies << {:gem => name, :requirements => requirements, :default => default_gem}
       end
 
+      def add_conflicts(*names)
+        @conflicts += names.map { |n| {:gem => n} }
+      end
+
+      def add_conflict(name, *req)
+        @conflicts << {:gem => name, :requirements => req.empty? ? nil : req}
+      end
+
       def self.bin=(bin)
         @bins = [bin].flatten
       end
@@ -323,6 +331,12 @@ module MRuby
               fail "#{name} version should be #{req_versions.join(' and ')} but was '#{dep_g.version}'"
             end
           end
+
+          cfls = g.conflicts.select { |c|
+            cfl_g = gem_table[c[:gem]]
+            cfl_g and cfl_g.version_ok?(c[:requirements] || ['>= 0.0.0'])
+          }.map { |c| "#{c[:gem]}(#{gem_table[c[:gem]].version})" }
+          fail "Conflicts of gem `#{g.name}` found: #{cfls.join ', '}" unless cfls.empty?
         end
 
         class << gem_table