Merge pull request #6846 from chef/lcg/add-nodemap-delete-class

add Chef::NodeMap#delete_class API

2 files changed, 53 insertions, 2 deletions

diff --git a/lib/chef/node_map.rb b/lib/chef/node_map.rb
index ecd5c9df8f..0406b3c1d6 100644
--- a/lib/chef/node_map.rb
+++ b/lib/chef/node_map.rb
@@ -118,6 +118,32 @@ class Chef
       end.map { |matcher| matcher[:klass] }
     end
 
+    # Remove a class from all its matchers in the node_map, will remove mappings completely if its the last matcher left
+    #
+    # Note that this leaks the internal structure out a bit, but the main consumer of this (poise/halite) cares only about
+    # the keys in the returned Hash.
+    #
+    # @param klass [Class] the class to seek and destroy
+    #
+    # @return [Hash] deleted entries in the same format as the @map
+    def delete_class(klass)
+      raise "please use a Class type for the klass argument" unless klass.is_a?(Class)
+      deleted = {}
+      map.each do |key, matchers|
+        deleted_matchers = []
+        matchers.delete_if do |matcher|
+          # because matcher[:klass] may be a string (which needs to die), coerce both to strings to compare somewhat canonically
+          if matcher[:klass].to_s == klass.to_s
+            deleted_matchers << matcher
+            true
+          end
+        end
+        deleted[key] = deleted_matchers unless deleted_matchers.empty?
+        map.delete(key) if matchers.empty?
+      end
+      deleted
+    end
+
     # Seriously, don't use this, it's nearly certain to change on you
     # @return remaining
     # @api private
diff --git a/spec/unit/node_map_spec.rb b/spec/unit/node_map_spec.rb
index 67bb741ec5..24f3bebe2a 100644
--- a/spec/unit/node_map_spec.rb
+++ b/spec/unit/node_map_spec.rb
@@ -19,6 +19,9 @@
 require "spec_helper"
 require "chef/node_map"
 
+class Foo; end
+class Bar; end
+
 describe Chef::NodeMap do
 
   let(:node_map) { Chef::NodeMap.new }
@@ -120,8 +123,6 @@ describe Chef::NodeMap do
   end
 
   describe "ordering classes" do
-    class Foo; end
-    class Bar; end
     it "last writer wins when its reverse alphabetic order" do
       node_map.set(:thing, Foo)
       node_map.set(:thing, Bar)
@@ -135,6 +136,30 @@ describe Chef::NodeMap do
     end
   end
 
+  describe "deleting classes" do
+    it "deletes a class and removes the mapping completely" do
+      node_map.set(:thing, Bar)
+      expect( node_map.delete_class(Bar) ).to eql({ :thing => [{ :klass => Bar }] })
+      expect( node_map.get(node, :thing) ).to eql(nil)
+    end
+
+    it "deletes a class and leaves the mapping that still has an entry" do
+      node_map.set(:thing, Bar)
+      node_map.set(:thing, Foo)
+      expect( node_map.delete_class(Bar) ).to eql({ :thing => [{ :klass => Bar }] })
+      expect( node_map.get(node, :thing) ).to eql(Foo)
+    end
+
+    it "handles deleting classes from multiple keys" do
+      node_map.set(:thing1, Bar)
+      node_map.set(:thing2, Bar)
+      node_map.set(:thing2, Foo)
+      expect( node_map.delete_class(Bar) ).to eql({ :thing1 => [{ :klass => Bar }], :thing2 => [{ :klass => Bar }] })
+      expect( node_map.get(node, :thing1) ).to eql(nil)
+      expect( node_map.get(node, :thing2) ).to eql(Foo)
+    end
+  end
+
   describe "with a block doing platform_version checks" do
     before do
       node_map.set(:thing, :foo, platform_family: "rhel") do |node|