Use Prism gem instead of Parser gem when Ruby 3.4+

lib/rspec/parameterized/core.rb

@@ -1,9 +1,8 @@
 require "rspec/parameterized/core/version"
-require 'parser'
-require 'unparser'
-require 'proc_to_ast'
 require 'rspec/parameterized/core/helper_methods'
 require 'rspec/parameterized/core/example_helper_methods'
+require 'rspec/parameterized/core/errors'
+require 'rspec/parameterized/core/composite_parser'
 
 module RSpec
   module Parameterized
@@ -143,11 +142,9 @@ def define_cases(parameter, *args, &block)
         end
 
         def params_inspect(obj)
-          begin
-            obj.is_a?(Proc) ? obj.to_raw_source : obj.inspect
-          rescue Parser::SyntaxError
-            return obj.inspect
-          end
+          RSpec::Parameterized::Core::CompositeParser.to_raw_source(obj)
+        rescue ParserSyntaxError
+          return obj.inspect
         end
 
         def set_verbose_parameters(&block)

lib/rspec/parameterized/core/composite_parser.rb

@@ -0,0 +1,75 @@
+module RSpec
+  module Parameterized
+    module Core
+      # Proxy class for parser and prism
+      module CompositeParser
+        # @param obj [Object]
+        # @return [String]
+        # @raise [RSpec::Parameterized::Core::ParserSyntaxError]
+        def self.to_raw_source(obj)
+          return to_raw_source_with_prism(obj) if use_prism?
+
+          to_raw_source_with_parser(obj)
+        end
+
+        # Whether use parser or prism
+        #
+        # @return [true] Use prism
+        # @return [false] Use parser
+        def self.use_prism?
+          Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("3.4.0")
+        end
+
+        # @param obj [Object]
+        # @return [String]
+        # @raise [RSpec::Parameterized::Core::ParserSyntaxError]
+        def self.to_raw_source_with_parser(obj)
+          obj.is_a?(Proc) ? obj.to_raw_source : obj.inspect
+        rescue Parser::SyntaxError => e
+          raise ParserSyntaxError
+        end
+        private_class_method :to_raw_source_with_parser
+
+        # @param obj [Object]
+        # @return [String]
+        def self.to_raw_source_with_prism(obj)
+          return obj.inspect unless obj.is_a?(Proc)
+
+          filename, linenum = obj.source_location
+          ast = parse_with_prism(filename, linenum)
+
+          return "" unless ast
+
+          ast.source.source.strip
+        end
+        private_class_method :to_raw_source_with_prism
+
+        # @param filename [String]
+        # @param linenum [Integer]
+        #
+        # @return [Prism::ParseResult,nil]
+        def self.parse_with_prism(filename, linenum)
+          buf = []
+          File.open(filename, "rb").each_with_index do |line, index|
+            next if index < linenum - 1
+            buf << line
+
+            ret = Prism.parse(buf.join)
+            return ret if ret.success?
+          end
+
+          nil
+        end
+        private_class_method :parse_with_prism
+      end
+    end
+  end
+end
+
+if RSpec::Parameterized::Core::CompositeParser.use_prism?
+  require 'prism'
+else
+  require 'parser'
+  require 'unparser'
+  require 'proc_to_ast'
+end

lib/rspec/parameterized/core/errors.rb

@@ -0,0 +1,9 @@
+module RSpec
+  module Parameterized
+    module Core
+      class Error < StandardError; end
+
+      class ParserSyntaxError < Error; end
+    end
+  end
+end

lib/rspec/parameterized/core/lazy_arg.rb

@@ -11,8 +11,8 @@ def apply(obj)
         end
 
         def inspect
-          "#{@block.to_raw_source}"
-        rescue Parser::SyntaxError
+          CompositeParser.to_raw_source(@block)
+        rescue ParserSyntaxError
           super.inspect
         end
       end

rspec-parameterized-core.gemspec

@@ -32,12 +32,18 @@ I was inspired by [udzura's mock](https://gist.github.com/1881139).}
   spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
+  spec.add_dependency "rspec", ">= 2.13", "< 4"
+
+  # parser dependencies
   spec.add_dependency "parser"
   spec.add_dependency "proc_to_ast", ">= 0.2.0"
-  spec.add_dependency "rspec", ">= 2.13", "< 4"
   spec.add_dependency "unparser"
 
+  # prism dependencies
+  spec.add_dependency "prism"
+
   spec.add_development_dependency "rake", ">= 12.0.0"
+  spec.add_development_dependency "rspec-its"
 
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html

spec/rspec/parameterized/core/composite_parser_spec.rb

@@ -0,0 +1,45 @@
+describe RSpec::Parameterized::Core::CompositeParser do
+  describe ".to_raw_source" do
+    subject { RSpec::Parameterized::Core::CompositeParser.to_raw_source(arg) }
+
+    context "arg is not proc" do
+      let(:arg) do
+        123
+      end
+
+      it { should eq "123" }
+    end
+
+    context "arg is proc" do
+      context "simple case" do
+        let(:arg) do
+          ->(a) { a + 1 }
+        end
+
+        it { should eq "->(a) { a + 1 }" }
+        its(:encoding) { should eq Encoding::UTF_8 }
+      end
+
+      context "arg is multibyte characters" do
+        let(:arg) do
+          ->(a) { a + "ほげほげ" }
+        end
+
+        it { should eq '->(a) { a + "ほげほげ" }' }
+        its(:encoding) { should eq Encoding::UTF_8 }
+      end
+
+      context "multiple lines" do
+        let(:arg) do
+          ->(a) {
+            a +
+              1
+          }
+        end
+
+        it { should eq "->(a) {\n            a +\n              1\n          }" }
+        its(:encoding) { should eq Encoding::UTF_8 }
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,5 +1,7 @@
 require 'rspec-parameterized-core'
 
+require 'rspec/its'
+
 RSpec.configure do |config|
   config.treat_symbols_as_metadata_keys_with_true_values = true
   config.run_all_when_everything_filtered = true