Add rewriter option to erase generics

lib/spoom/cli/srb/sigs.rb

@@ -22,6 +22,10 @@ class Sigs < Thor
         option :translate_generics, type: :boolean, desc: "Translate generics", default: false
         option :translate_helpers, type: :boolean, desc: "Translate helpers", default: false
         option :translate_abstract_methods, type: :boolean, desc: "Translate abstract methods", default: false
+        option :erase_generic_types,
+          type: :boolean,
+          desc: "Drop generic types when translating from RBS to RBI",
+          default: false
         def translate(*paths)
           from = options[:from]
           to = options[:to]
@@ -65,6 +69,7 @@ def translate(*paths)
                 contents,
                 file: file,
                 max_line_length: max_line_length,
+                erase_generic_types: options[:erase_generic_types],
               )
             end
           end

lib/spoom/sorbet/translate.rb

@@ -53,13 +53,15 @@ def sorbet_sigs_to_rbs_comments(
 
         # Converts all the RBS comments in the given Ruby code to `sig` nodes.
         # It also handles type members and class annotations.
-        #: (String ruby_contents, file: String, ?max_line_length: Integer?, ?overloads_strategy: Symbol) -> String
-        def rbs_comments_to_sorbet_sigs(ruby_contents, file:, max_line_length: nil, overloads_strategy: :translate_all)
+        #: (String ruby_contents, file: String, ?max_line_length: Integer?, ?overloads_strategy: Symbol, ?erase_generic_types: bool) -> String
+        def rbs_comments_to_sorbet_sigs(ruby_contents, file:, max_line_length: nil, overloads_strategy: :translate_all,
+          erase_generic_types: false)
           RBSCommentsToSorbetSigs.rewrite_if_needed(
             ruby_contents,
             file: file,
             max_line_length: max_line_length,
             overloads_strategy: overloads_strategy,
+            erase_generic_types: erase_generic_types,
           )
         end
 

lib/spoom/sorbet/translate/rbs_comments_to_sorbet_sigs.rb

@@ -28,16 +28,18 @@ def contains_rbs_syntax?(source)
             Sigils.contains_valid_sigil?(source) && source.match?(RBS_REWRITE_PATTERN)
           end
 
-          #: (String ruby_contents, file: String, ?max_line_length: Integer?, ?overloads_strategy: Symbol) -> String
-          def rewrite_if_needed(ruby_contents, file:, max_line_length: nil, overloads_strategy: :translate_all)
+          #: (String ruby_contents, file: String, ?max_line_length: Integer?, ?overloads_strategy: Symbol, ?erase_generic_types: bool) -> String
+          def rewrite_if_needed(ruby_contents, file:, max_line_length: nil, overloads_strategy: :translate_all,
+            erase_generic_types: false)
             return ruby_contents unless contains_rbs_syntax?(ruby_contents)
 
-            new(ruby_contents, file:, max_line_length:, overloads_strategy:).rewrite
+            new(ruby_contents, file:, max_line_length:, overloads_strategy:, erase_generic_types:).rewrite
           end
         end
 
-        #: (String, file: String, ?max_line_length: Integer?, ?overloads_strategy: Symbol) -> void
-        def initialize(ruby_contents, file:, max_line_length: nil, overloads_strategy: :translate_all)
+        #: (String, file: String, ?max_line_length: Integer?, ?overloads_strategy: Symbol, ?erase_generic_types: bool) -> void
+        def initialize(ruby_contents, file:, max_line_length: nil, overloads_strategy: :translate_all,
+          erase_generic_types: false)
           super(ruby_contents, file: file)
 
           unless ALLOWED_OVERLOAD_STRATEGIES.include?(overloads_strategy)
@@ -47,6 +49,8 @@ def initialize(ruby_contents, file:, max_line_length: nil, overloads_strategy: :
 
           @max_line_length = max_line_length
           @overloads_strategy = overloads_strategy
+          @erase_generic_types = erase_generic_types
+          @type_translator = RBI::RBS::TypeTranslator.new(erase_generic_types:) #: RBI::RBS::TypeTranslator
         end
 
         # @override
@@ -133,11 +137,11 @@ def visit_attr(node)
               name = node.arguments&.arguments&.first #: as Prism::SymbolNode
               sig.params << RBI::SigParam.new(
                 name.slice[1..-1], #: as String
-                RBI::RBS::TypeTranslator.translate(attr_type),
+                @type_translator.translate(attr_type),
               )
             end
 
-            sig.return_type = RBI::RBS::TypeTranslator.translate(attr_type)
+            sig.return_type = @type_translator.translate(attr_type)
 
             apply_member_annotations(comments.method_annotations, sig)
 
@@ -174,7 +178,7 @@ def rewrite_def(def_node, comments)
               next
             end
 
-            translator = RBI::RBS::MethodTypeTranslator.new(rbi_node)
+            translator = RBI::RBS::MethodTypeTranslator.new(rbi_node, erase_generic_types: @erase_generic_types)
 
             begin
               translator.visit(method_type)
@@ -259,7 +263,7 @@ def apply_class_annotations(node)
                 "final!"
               when /^@requires_ancestor: /
                 srb_type = ::RBS::Parser.parse_type(annotation.string.delete_prefix("@requires_ancestor: "))
-                rbs_type = RBI::RBS::TypeTranslator.translate(srb_type)
+                rbs_type = @type_translator.translate(srb_type)
                 "requires_ancestor { #{rbs_type} }"
               else
                 next
@@ -288,6 +292,17 @@ def apply_class_annotations(node)
               to = adjust_to_line_end(signature.location.end_offset)
               @rewriter << Source::Delete.new(from, to)
 
+              if @erase_generic_types
+                type_params.each do |type_param|
+                  @rewriter << Source::Insert.new(
+                    insert_pos,
+                    "\n#{indent}#{type_param.name} = T.type_alias { T.anything }\n",
+                  )
+                end
+
+                next
+              end
+
               unless already_extends?(node, /^(::)?T::Generic$/)
                 @rewriter << Source::Insert.new(insert_pos, "\n#{indent}extend T::Generic\n")
               end
@@ -304,12 +319,12 @@ def apply_class_annotations(node)
 
                 if type_param.upper_bound || type_param.default_type
                   if type_param.upper_bound
-                    rbs_type = RBI::RBS::TypeTranslator.translate(type_param.upper_bound)
+                    rbs_type = @type_translator.translate(type_param.upper_bound)
                     type_member = "#{type_member} {{ upper: #{rbs_type} }}"
                   end
 
                   if type_param.default_type
-                    rbs_type = RBI::RBS::TypeTranslator.translate(type_param.default_type)
+                    rbs_type = @type_translator.translate(type_param.default_type)
                     type_member = "#{type_member} {{ fixed: #{rbs_type} }}"
                   end
                 end
@@ -417,7 +432,7 @@ def apply_type_aliases(comments)
             next unless decls.size == 1 && decls.first.is_a?(::RBS::AST::Declarations::TypeAlias)
 
             rbs_type = decls.first
-            sorbet_type = RBI::RBS::TypeTranslator.translate(rbs_type.type)
+            sorbet_type = @type_translator.translate(rbs_type.type)
 
             alias_name = ::RBS::TypeName.new(
               namespace: rbs_type.name.namespace,

test/spoom/cli/srb/sigs_test.rb

@@ -197,6 +197,46 @@ def foo(a, b = 42, *c, d:, e: 42, **f); end
           RB
         end
 
+        def test_translate_rbs_to_rbi_with_erase_generic_types
+          @project.write!("file.rb", <<~RB)
+            # typed: true
+
+            #: [E]
+            class Box
+              #: -> Array[E]
+              def values
+                []
+              end
+
+              #: (E) -> void
+              def push(value)
+              end
+            end
+          RB
+
+          result = @project.spoom("srb sigs translate --from rbs --to rbi --no-color --erase-generic-types")
+
+          assert_empty(result.err)
+          assert(result.status)
+
+          assert_equal(<<~RB, @project.read("file.rb"))
+            # typed: true
+
+            class Box
+              E = T.type_alias { T.anything }
+
+              sig { returns(Array) }
+              def values
+                []
+              end
+
+              sig { params(value: E).void }
+              def push(value)
+              end
+            end
+          RB
+        end
+
         def test_translate_includes_rbi_files
           @project.write!("file.rb", <<~RB)
             sig { void }