From 1d1bf71f1e91cdc650cbe35c054779d85f75c6db Mon Sep 17 00:00:00 2001
From: Jean-Philippe <jpduchesne89@gmail.com>
Date: Sat, 21 Feb 2026 14:41:52 -0500
Subject: [PATCH] Add Ruby 4.0 support via Prism parser

Switch from Parser::CurrentRuby to Prism::Translation::Parser for
future-proof Ruby 4.0+ syntax support. Parser::CurrentRuby silently
falls back to Ruby33 parser on Ruby 4.0 since the parser gem doesn't
know about it yet.

- Replace Parser::CurrentRuby with Prism::Translation::Parser
- Use Prism::Translation::Parser::Builder as default builder
- Add explicit prism runtime dependency
- Add Ruby 4.0 to CI matrix
- Bump version to 2.1.0

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 .github/workflows/ci.yml         | 2 +-
 Gemfile.lock                     | 3 ++-
 ast_transform.gemspec            | 1 +
 lib/ast_transform/source_map.rb  | 2 +-
 lib/ast_transform/transformer.rb | 9 +++++----
 lib/ast_transform/version.rb     | 2 +-
 6 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 869fdad..66ef1de 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ['3.2', '3.3']
+        ruby: ['3.2', '3.3', '4.0']
     steps:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
diff --git a/Gemfile.lock b/Gemfile.lock
index 812d8e3..c8e16a7 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,8 +1,9 @@
 PATH
   remote: .
   specs:
-    ast_transform (2.0.0)
+    ast_transform (2.1.0)
       parser (>= 3.0)
+      prism (>= 1.5)
       unparser (>= 0.6)
 
 GEM
diff --git a/ast_transform.gemspec b/ast_transform.gemspec
index e8cf193..e93e0c3 100644
--- a/ast_transform.gemspec
+++ b/ast_transform.gemspec
@@ -31,5 +31,6 @@ Gem::Specification.new do |spec|
 
   # Runtime dependencies
   spec.add_runtime_dependency "parser", ">= 3.0"
+  spec.add_runtime_dependency "prism", ">= 1.5"
   spec.add_runtime_dependency "unparser", ">= 0.6"
 end
diff --git a/lib/ast_transform/source_map.rb b/lib/ast_transform/source_map.rb
index ba61603..ae73ee2 100644
--- a/lib/ast_transform/source_map.rb
+++ b/lib/ast_transform/source_map.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require 'parser/current'
+require 'parser'
 
 module ASTTransform
   class SourceMap
diff --git a/lib/ast_transform/transformer.rb b/lib/ast_transform/transformer.rb
index a373fc5..4d53ea1 100644
--- a/lib/ast_transform/transformer.rb
+++ b/lib/ast_transform/transformer.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
-require 'parser/current'
+require 'prism'
+require 'prism/translation/parser'
 require 'unparser'
 require 'ast_transform/source_map'
 
@@ -8,8 +9,8 @@ class Transformer
     # Constructs a new Transformer instance.
     #
     # @param transformations [Array<ASTTransform::AbstractTransformation>] The transformations to be run.
-    # @param builder [Parser::Builders::Default] The AST Node builder.
-    def initialize(*transformations, builder: Parser::Builders::Default.new)
+    # @param builder [Prism::Translation::Parser::Builder] The AST Node builder.
+    def initialize(*transformations, builder: Prism::Translation::Parser::Builder.new)
       @transformations = transformations
       @builder = builder
     end
@@ -99,7 +100,7 @@ def create_buffer(source, file_path)
 
     def parser
       @parser&.reset
-      @parser ||= Parser::CurrentRuby.new(@builder)
+      @parser ||= Prism::Translation::Parser.new(@builder)
     end
 
     def register_source_map(source_file_path, transformed_file_path, transformed_ast, transformed_source)
diff --git a/lib/ast_transform/version.rb b/lib/ast_transform/version.rb
index 02ae8cf..1e638f8 100644
--- a/lib/ast_transform/version.rb
+++ b/lib/ast_transform/version.rb
@@ -1,3 +1,3 @@
 module ASTTransform
-  VERSION = "2.0.0"
+  VERSION = "2.1.0"
 end