FC026: Conditional contains only string, refs #30.

features/026_check_for_conditional_block_string.feature

@@ -0,0 +1,20 @@
+Feature: Check for conditional attribute blocks with only strings
+
+  In order to avoid wrongly actioning a resource
+  As a developer
+  I want to identify conditional attribute blocks that consist only of strings
+
+  Scenario Outline:
+    Given a cookbook recipe that declares a resource with a <conditional_attribute>
+    When I check the cookbook
+    Then the conditional block contains only string warning 026 should be <show_warning>
+
+  Examples:
+    | conditional_attribute                   | show_warning |
+    | not_if { "ls foo" }                     | shown        |
+    | not_if do "ls foo" end                  | shown        |
+    | only_if { "ls #{node['foo']['path']}" } | shown        |
+    | not_if { "ls #{foo.method()}" }         | shown        |
+    | only_if { foo.bar }                     | not shown    |
+    | not_if { foo.to_s }                     | not shown    |
+    | not_if { File.exists?("/etc/foo") }     | not shown    |

features/step_definitions/cookbook_steps.rb

@@ -943,6 +943,10 @@ def search(bag_name, query=nil, sort=nil, start=0, rows=1000, &block)
   expect_warning('FC024', :line => should_not.nil? ? @expected_line : nil, :expect_warning => should_not.nil?)
 end
 
+Then /^the conditional block contains only string warning 026 should be (shown|not shown)$/ do |show_warning|
+  expect_warning('FC026', :line => nil, :expect_warning => show_warning == 'shown')
+end
+
 Then /^the conditional string looks like ruby warning 020 should be (shown|not shown)$/ do |show_warning|
   expect_warning('FC020', :line => nil, :expect_warning => show_warning == 'shown')
 end

features/support/command_helpers.rb

@@ -32,6 +32,7 @@ module CommandHelpers
       'FC023' => 'Prefer conditional attributes',
       'FC024' => 'Consider adding platform equivalents',
       'FC025' => 'Prefer chef_gem to compile-time gem install',
+      'FC026' => 'Conditional execution block attribute contains only string',
       'FCTEST001' => 'Test Rule'
     }
 

lib/foodcritic/rules.rb

@@ -362,3 +362,19 @@
     end
   end
 end
+
+rule "FC026", "Conditional execution block attribute contains only string" do
+  tags %w{correctness}
+  applies_to {|version| version >= gem_version("0.7.4")}
+  recipe do |ast|
+    find_resources(ast).map{|r| resource_attributes(r)}.map do |resource|
+      [resource['not_if'], resource['only_if']]
+    end.flatten.compact.select do |condition|
+      condition.respond_to?(:xpath) and
+      ! condition.xpath('descendant::string_literal').empty? and
+        ! condition.xpath('stmts_add/string_literal').empty? and
+        condition.xpath('descendant::stmts_add[count(ancestor::
+          string_literal) = 0]').size == 1
+    end
+  end
+end