Compiler for GraphQL::Schema

Which creates a strongly-typed sig for `#context`, if the context class was customized via the `context_class`  DSL.

lib/tapioca/dsl/compilers/graphql_schema.rb

@@ -0,0 +1,70 @@
+# typed: strict
+# frozen_string_literal: true
+
+begin
+  gem("graphql", ">= 1.13")
+  require "graphql"
+rescue LoadError
+  return
+end
+
+require "tapioca/dsl/helpers/graphql_type_helper"
+
+module Tapioca
+  module Dsl
+    module Compilers
+      # `Tapioca::Dsl::Compilers::GraphqlSchema` generates RBI files for subclasses of
+      # [`GraphQL::Schema`](https://graphql-ruby.org/api-doc/2.1.7/GraphQL/Schema).
+      #
+      # For example, with the following `GraphQL::Schema` subclass:
+      #
+      # ~~~rb
+      # class MySchema> < GraphQL::Schema
+      #   class MyContext < GraphQL::Query::Context; end
+      #
+      #   context_class MyContext
+      #
+      #   # ...
+      # end
+      # ~~~
+      #
+      # this compiler will produce the RBI file `my_schema.rbi` with the following content:
+      #
+      # ~~~rbi
+      # # my_schema.rbi
+      # # typed: true
+      # class MySchema
+      #   sig { returns(MySchema::MyContext) }
+      #   def context; end
+      # end
+      # ~~~
+      class GraphqlSchema < Compiler
+        extend T::Sig
+
+        ConstantType = type_member { { fixed: T.class_of(GraphQL::Schema) } }
+
+        sig { override.void }
+        def decorate
+          custom_context_class = constant.context_class
+          # Skip decoration if the context class hasn't been customized
+          return if custom_context_class == GraphQL::Query::Context
+
+          return if constant.method_defined?(:context, false) # Skip if the Schema overrides the `#context` getter.
+
+          root.create_path(constant) do |schema|
+            schema.create_method("context", return_type: T.must(name_of(custom_context_class)))
+          end
+        end
+
+        class << self
+          extend T::Sig
+
+          sig { override.returns(T::Enumerable[Module]) }
+          def gather_constants
+            all_classes.select { |c| c < GraphQL::Schema && c != GraphQL::Query::NullContext::NullSchema }
+          end
+        end
+      end
+    end
+  end
+end

manual/compiler_graphqlschema.md

@@ -0,0 +1,27 @@
+## GraphqlSchema
+
+`Tapioca::Dsl::Compilers::GraphqlSchema` generates RBI files for subclasses of
+[`GraphQL::Schema`](https://graphql-ruby.org/api-doc/2.1.7/GraphQL/Schema).
+
+For example, with the following `GraphQL::Schema` subclass:
+
+~~~rb
+class MySchema> < GraphQL::Schema
+  class MyContext < GraphQL::Query::Context; end
+
+  context_class MyContext
+
+  # ...
+end
+~~~
+
+this compiler will produce the RBI file `my_schema.rbi` with the following content:
+
+~~~rbi
+# my_schema.rbi
+# typed: true
+class MySchema
+  sig { returns(MySchema::MyContext) }
+  def context; end
+end
+~~~

manual/compilers.md

@@ -28,6 +28,7 @@ In the following section you will find all available DSL compilers:
 * [FrozenRecord](compiler_frozenrecord.md)
 * [GraphqlInputObject](compiler_graphqlinputobject.md)
 * [GraphqlMutation](compiler_graphqlmutation.md)
+* [GraphqlSchema](compiler_graphqlschema.md)
 * [IdentityCache](compiler_identitycache.md)
 * [JsonApiClientResource](compiler_jsonapiclientresource.md)
 * [Kredis](compiler_kredis.md)

spec/tapioca/dsl/compilers/graphql_schema_spec.rb

@@ -0,0 +1,103 @@
+# typed: strict
+# frozen_string_literal: true
+
+require "spec_helper"
+
+module Tapioca
+  module Dsl
+    module Compilers
+      class GraphqlSchemaSpec < ::DslSpec
+        describe "Tapioca::Dsl::Compilers::GraphqlSchema" do
+          describe "initialize" do
+            it "gathers no constants if there are no GraphQL::Schema subclasses" do
+              assert_empty(gathered_constants)
+            end
+
+            it "gathers only GraphQL::Schema subclasses" do
+              add_ruby_file("content.rb", <<~RUBY)
+                class MySchema < GraphQL::Schema
+                end
+
+                class User
+                end
+              RUBY
+
+              assert_equal(["MySchema"], gathered_constants)
+            end
+
+            it "gathers subclasses of GraphQL::Schema subclasses" do
+              add_ruby_file("content.rb", <<~RUBY)
+                class MyBaseSchema < GraphQL::Schema
+                end
+
+                class MySchema < MyBaseSchema
+                end
+              RUBY
+
+              assert_equal(["MyBaseSchema", "MySchema"], gathered_constants)
+            end
+          end
+
+          describe "decorate" do
+            it "generates an empty RBI file if there is no custom context_class is set" do
+              add_ruby_file("create_comment.rb", <<~RUBY)
+                class MySchema < GraphQL::Schema
+                end
+              RUBY
+
+              expected = <<~RBI
+                # typed: strong
+              RBI
+
+              assert_equal(expected, rbi_for(:MySchema))
+            end
+
+            it "generates correct RBI file for subclass that sets context_class" do
+              add_ruby_file("create_comment.rb", <<~RUBY)
+                class MySchema < GraphQL::Schema
+                  class MyContext < GraphQL::Query::Context; end
+
+                  context_class MyContext
+                end
+              RUBY
+
+              expected = <<~RBI
+                # typed: strong
+
+                class MySchema
+                  sig { returns(MySchema::MyContext) }
+                  def context; end
+                end
+              RBI
+
+              assert_equal(expected, rbi_for(:MySchema))
+            end
+
+            it "generates an empty RBI file if there is an inline signature" do
+              add_ruby_file("create_comment.rb", <<~RUBY)
+                class MySchema < GraphQL::Schema
+                  extend T::Sig
+
+                  class MyContext < GraphQL::Query::Context; end
+
+                  context_class MyContext
+
+                  sig { returns(SomethingElse) }
+                  def context
+                    # ...
+                  end
+                end
+              RUBY
+
+              expected = <<~RBI
+                # typed: strong
+              RBI
+
+              assert_equal(expected, rbi_for(:MySchema))
+            end
+          end
+        end
+      end
+    end
+  end
+end