Fix metadatable type in poly_metadata relationship on Well

app/models/well.rb

@@ -48,6 +48,19 @@
   has_many :target_well_links, -> { stock }, class_name: 'Well::Link', foreign_key: :source_well_id
   has_many :target_wells, through: :target_well_links, source: :target_well
 
+  # Can have many key value pairs of metadata
+  has_many :poly_metadata, as: :metadatable, dependent: :destroy
+
+  # Returns a collection of PolyMetadatum records associated with the Well.
+  # This method overrides the autogenerated poly_metadata method to pick the
+  # correct metadatable_type instead of the parent type. Without this override,
+  # the generated SQL uses the wrong class name, e.g. Receptacle instead of Well.
+  #
+  # @return [ActiveRecord::Relation] a collection of PolyMetadatum records
+  def poly_metadata
+    PolyMetadatum.where(metadatable_id: id, metadatable_type: self.class.name)
+  end
+
   belongs_to :plate, foreign_key: :labware_id
   has_one :well_attribute, inverse_of: :well
 

app/resources/api/v2/well_resource.rb

@@ -21,6 +21,8 @@ class WellResource < BaseResource
       # Attributes
       attribute :position, readonly: true
 
+      has_many :poly_metadata, as: :metadatable, class_name: 'PolyMetadatum'
+
       def position
         { 'name' => _model.map_description }
       end