Override the #to_yaml method for ImmutableMash & ImmutableArray

 - Psych module to_yaml not working as expected for ImmutableMash & ImmutableArray.
 - So parse first to Hash/Array then convert it to YAML formatted string.

Signed-off-by: Vivek Singh <vivek.singh@msystechnologies.com>

2 files changed, 40 insertions, 0 deletions

diff --git a/lib/chef/node/immutable_collections.rb b/lib/chef/node/immutable_collections.rb
index b4a7a39ba0..96e589fdaa 100644
--- a/lib/chef/node/immutable_collections.rb
+++ b/lib/chef/node/immutable_collections.rb
@@ -96,6 +96,12 @@ class Chef
 
       alias_method :to_array, :to_a
 
+      # As Psych module, not respecting Immutable ImmutableArray object
+      # So first convert it to Hash/Array then parse it to `.to_yaml`
+      def to_yaml(*opts)
+        to_a.to_yaml(*opts)
+      end
+
       private
 
       # needed for __path__
@@ -168,6 +174,12 @@ class Chef
 
       alias_method :to_hash, :to_h
 
+      # As Psych module, not respecting ImmutableMash object
+      # So first convert it to Hash/Array then parse it to `.to_yaml`
+      def to_yaml(*opts)
+        to_h.to_yaml(*opts)
+      end
+
       # For elements like Fixnums, true, nil...
       def safe_dup(e)
         e.dup
diff --git a/spec/unit/node/immutable_collections_spec.rb b/spec/unit/node/immutable_collections_spec.rb
index f23e40dc4c..e9697c320f 100644
--- a/spec/unit/node/immutable_collections_spec.rb
+++ b/spec/unit/node/immutable_collections_spec.rb
@@ -145,6 +145,20 @@ describe Chef::Node::ImmutableMash do
     end
   end
 
+  describe "to_yaml" do
+    before do
+      @copy = @immutable_mash.to_yaml
+    end
+
+    it "converts an immutable mash to a new mutable YAML formatted string" do
+      expect(@copy).to be_instance_of(String)
+    end
+
+    it "should create a YAML formatted string with the content" do
+      expect(@copy).to eq("---\ntop:\n  second_level: some value\ntop_level_2:\n- array\n- of\n- values\ntop_level_3:\n- hash_array: 1\n  hash_array_b: 2\ntop_level_4:\n  level2:\n    key: value\n")
+    end
+  end
+
   %i{
     []=
     clear
@@ -318,6 +332,20 @@ describe Chef::Node::ImmutableArray do
     end
   end
 
+  describe "to_yaml" do
+    before do
+      @copy = @immutable_nested_array.to_yaml
+    end
+
+    it "converts an immutable array to a new YAML formatted mutable string" do
+      expect(@copy).to be_instance_of(String)
+    end
+
+    it "should create a YAML formatted string with content" do
+      expect(@copy).to eq("---\n- level1\n- - foo\n  - bar\n  - baz\n  - 1\n  - 2\n  - 3\n  - \n  - true\n  - false\n  - - el\n    - 0\n    - \n- m: m\n")
+    end
+  end
+
   describe "#[]" do
     it "works with array slices" do
       expect(@immutable_array[1, 2]).to eql(%w{bar baz})