MONGOID 5800 When initializing an embedded association with an invalid hash, got undefined method `with_indifferent_access' error (#6075)

* Adds support for single hash input in nested attributes for has_many associations.

* Adding a check to initialize()

* add with_indifferent_access to array

* fixing how we handle arrays

* empty commit

* adding more guards in build()

* Adding handling for if the array has uneven number of elements

Author: kyleburgess2025

lib/mongoid/association/nested/many.rb

@@ -16,6 +16,9 @@ class Many
         # This attempts to perform 3 operations, either one of an update of
         # the existing association, a replacement of the association with a new
         # document, or a removal of the association.
+        # 
+        # It raises an argument error if the attributes are not a Hash or an 
+        # Array of key/value pairs.
         #
         # @example Build the nested attrs.
         #   many.build(person)
@@ -32,8 +35,12 @@ def build(parent, options = {})
           attributes.each do |attrs|
             if attrs.is_a?(::Hash)
               process_attributes(parent, attrs.with_indifferent_access)
-            else
+            elsif attrs.is_a?(Array) && attrs.length > 1 && attrs[1].respond_to?(:with_indifferent_access)
               process_attributes(parent, attrs[1].with_indifferent_access)
+            elsif attrs.is_a?(Array) && attrs.length.even?
+              process_attributes(parent, Hash[*attrs].with_indifferent_access)
+            else
+              raise ArgumentError, "Attributes for nested association '#{association.name}' must be a Hash or an Array of key/value pairs."
             end
           end
         end

spec/integration/associations/embeds_many_spec.rb

@@ -327,4 +327,20 @@ class Comment
       end
     end
   end
+
+  context "when a hash is provided instead of an array for an embeds_many association" do
+    let(:post) { EmbedsManySpec::Post.new(title: 'Broken post', comments: { content: 'Comment' }) }
+
+    it "does not raise an error on initialization" do
+      expect { post }.to_not raise_error
+    end
+
+    it "does not raise an error when accessing the association" do
+      expect { post.comments }.to_not raise_error
+    end
+
+    it "allows building new documents on the association" do
+      expect(post.comments.build).to be_a EmbedsManySpec::Comment
+    end
+  end
 end