Merge pull request #2630 from Shopify/kaan/fix-rbs-rewriter-bootsnap-default

Restore `Bootsnap` fallback for RBS rewriting

Author: KaanOzkan

lib/tapioca/rbs/rewriter.rb

@@ -58,9 +58,37 @@ def setup(**_kwargs)
   rescue LoadError
     # Bootsnap is not in the bundle, skip iseq caching.
   end
-end
 
-require "require-hooks/setup"
+  require "require-hooks/setup"
+else
+  require "require-hooks/setup"
+
+  begin
+    # Disable Bootsnap's iseq cache unless TAPIOCA_RBS_CACHE=1 enabled the separate cache above.
+    #
+    # This is necessary because host apps can call Bootsnap.setup after tapioca loads this file. When that happens,
+    # Bootsnap installs `load_iseq` and serves files from its cache, which bypasses RequireHooks.source_transform.
+    # Preloading bootsnap's iseq support lets us override `load_iseq` before setup installs it, preserving the default
+    # RBS rewrite behavior at the cost of slower app boot.
+    require "bootsnap"
+    require "bootsnap/compile_cache/iseq"
+
+    module Bootsnap
+      module CompileCache
+        module ISeq
+          module InstructionSequenceMixin
+            #: (String) -> RubyVM::InstructionSequence
+            def load_iseq(path)
+              super if defined?(super) # Disable Bootsnap's hook, but trigger any others.
+            end
+          end
+        end
+      end
+    end
+  rescue LoadError
+    # Bootsnap is not in the bundle, we don't need to do anything.
+  end
+end
 
 # We need to include `T::Sig` very early to make sure that the `sig` method is available since gems using RBS comments
 # are unlikely to include `T::Sig` in their own classes.

spec/tapioca/cli/dsl_spec.rb

@@ -680,6 +680,65 @@ class Post
           assert_success_status(result)
         end
 
+        it "preserves RBS comment rewriting when the host sets up Bootsnap without TAPIOCA_RBS_CACHE" do
+          @project.write!("lib/00_bootsnap.rb", <<~RB)
+            require "bootsnap"
+            Bootsnap.setup(cache_dir: File.join(Dir.pwd, "tmp/cache/host-bootsnap"))
+          RB
+
+          @project.write!("lib/post.rb", <<~RB)
+            # typed: strict
+
+            class Post
+              #: -> String
+              def title
+                "hello"
+              end
+            end
+          RB
+
+          @project.write!("lib/compilers/rbs_comment_compiler.rb", <<~RB)
+            require "post"
+
+            class RbsCommentCompiler < Tapioca::Dsl::Compiler
+              extend T::Sig
+              extend T::Generic
+
+              ConstantType = type_member { { fixed: T.class_of(::Post) } }
+
+              sig { override.void }
+              def decorate
+                root.create_path(constant) do |klass|
+                  create_method_from_def(klass, constant.instance_method(:title))
+                end
+              end
+
+              sig { override.returns(T::Enumerable[T::Module[T.anything]]) }
+              def self.gather_constants
+                [::Post]
+              end
+            end
+          RB
+
+          result = @project.tapioca("dsl Post --only RbsCommentCompiler")
+
+          assert_empty_stderr(result)
+          assert_project_file_equal("sorbet/rbi/dsl/post.rbi", <<~RBI)
+            # typed: true
+
+            # DO NOT EDIT MANUALLY
+            # This is an autogenerated file for dynamic methods in `Post`.
+            # Please instead update this file by running `bin/tapioca dsl Post`.
+
+
+            class Post
+              sig { returns(::String) }
+              def title; end
+            end
+          RBI
+          assert_success_status(result)
+        end
+
         it "raises when the host calls Bootsnap.setup under TAPIOCA_RBS_CACHE=1" do
           @project.write!("lib/post.rb", <<~RB)
             require "bootsnap"