Address review feedback on JSON ingestion spec migration

- Trim the JSON-schema-versioning scenarios from the core `rake_tasks_spec`
  that are now covered by `schema_artifact_manager_extension_spec` in
  `elasticgraph-json_ingestion`, and remove the helpers that only those
  scenarios used.
- Replace the core coverage those scenarios provided with focused unit specs:
  the `deleted_type`/`deleted_field`/`renamed_from` registration DSL,
  `FieldPath#fully_qualified_path_in_index`, and the test-support behavior
  when a schema sets its own JSON schema version.
- Make `doc_comment` load-bearing in the wrapper equality specs by adding
  cases that differ only in `doc_comment`.
- Assert on observable behavior instead of `singleton_class.ancestors` in
  the blockless-element extension spec.
- Explain why `unresolved_type_ref` uses a stand-in.

Author: jwils

elasticgraph-json_ingestion/spec/unit/elastic_graph/json_ingestion/schema_definition/indexing/wrappers_spec.rb

@@ -32,11 +32,18 @@ module Indexing
               json_schema_customizations: {maxLength: 10},
               doc_comment: reference.doc_comment
             )
+            different_doc_reference = FieldReference.new(
+              reference.__getobj__,
+              json_schema_layers: reference.json_schema_layers,
+              json_schema_customizations: reference.json_schema_customizations,
+              doc_comment: "alternate docs"
+            )
 
             expect(reference).to eq(matching_reference)
             expect(reference.eql?(matching_reference)).to eq(true)
             expect(reference.hash).to eq(matching_reference.hash)
             expect(reference).not_to eq(different_reference)
+            expect(reference).not_to eq(different_doc_reference)
             expect(reference == reference.__getobj__).to eq(true)
           end
 
@@ -73,11 +80,18 @@ module Indexing
               json_schema_customizations: {maxLength: 10},
               doc_comment: field.doc_comment
             )
+            different_doc_field = Field.new(
+              field.__getobj__,
+              json_schema_layers: field.json_schema_layers,
+              json_schema_customizations: field.json_schema_customizations,
+              doc_comment: "alternate docs"
+            )
 
             expect(field).to eq(matching_field)
             expect(field.eql?(matching_field)).to eq(true)
             expect(field.hash).to eq(matching_field.hash)
             expect(field).not_to eq(different_field)
+            expect(field).not_to eq(different_doc_field)
             expect(field == field.__getobj__).to eq(true)
           end
 
@@ -89,11 +103,16 @@ module Indexing
             different_object_field_type = FieldType::Object.new(object_field_type.__getobj__).tap do |field_type|
               field_type.json_schema_options = {type: "object"}
             end
+            different_doc_object_field_type = FieldType::Object.new(object_field_type.__getobj__).tap do |field_type|
+              field_type.json_schema_options = object_field_type.json_schema_options
+              field_type.doc_comment = "alternate docs"
+            end
 
             expect(object_field_type).to eq(matching_object_field_type)
             expect(object_field_type.eql?(matching_object_field_type)).to eq(true)
             expect(object_field_type.hash).to eq(matching_object_field_type.hash)
             expect(object_field_type).not_to eq(different_object_field_type)
+            expect(object_field_type).not_to eq(different_doc_object_field_type)
             expect(object_field_type == object_field_type.__getobj__).to eq(true)
           end
 
@@ -120,6 +139,9 @@ def widget_type
             end.state.object_types_by_name.fetch("Widget")
           end
 
+          # A minimal stand-in for a `SchemaElements::TypeReference` that never resolves. References to
+          # not-yet-defined types resolve to `nil` mid-definition; a stand-in lets us exercise that path
+          # directly instead of relying on the timing of a partially-defined schema.
           def unresolved_type_ref
             Class.new do
               def fully_unwrapped

elasticgraph-json_ingestion/spec/unit/elastic_graph/json_ingestion/schema_definition/schema_elements/scalar_type_extension_spec.rb

@@ -39,9 +39,20 @@ module SchemaElements
               field_factory: api.factory.method(:new_field)
             )
 
-            expect(api.state.enum_types_by_name.fetch("EmptyEnum").singleton_class.ancestors).to include(EnumTypeExtension)
-            expect(api.state.object_types_by_name.fetch("EmptyInterface").__getobj__.singleton_class.ancestors).to include(TypeWithSubfieldsExtension)
-            expect(direct_type_with_subfields.singleton_class.ancestors).to include(TypeWithSubfieldsExtension)
+            # An enum's derived GraphQL types are built from a derived scalar twin, which can only be
+            # built if `EnumTypeExtension` configured the twin's `json_schema`; otherwise building it
+            # raises a "lacks `json_schema`" error.
+            expect {
+              api.state.enum_types_by_name.fetch("EmptyEnum").derived_graphql_types
+            }.not_to raise_error
+
+            # `json_schema` is only available on types extended with `TypeWithSubfieldsExtension`.
+            interface_type = api.state.object_types_by_name.fetch("EmptyInterface")
+            interface_type.json_schema minProperties: 1
+            expect(interface_type.json_schema_options).to eq({minProperties: 1})
+
+            direct_type_with_subfields.json_schema minProperties: 2
+            expect(direct_type_with_subfields.json_schema_options).to eq({minProperties: 2})
 
             expect {
               build_api.scalar_type "BigInt"