ruby-git · jcouball · Jul 6, 2025 · Jul 6, 2025
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
@@ -1,27 +1,22 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2025-07-05 15:13:23 UTC using RuboCop version 1.77.0.
+# on 2025-07-06 05:52:16 UTC using RuboCop version 1.77.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 56
+# Offense count: 50
 # Configuration parameters: AllowedMethods, AllowedPatterns, CountRepeatedAttributes.
 Metrics/AbcSize:
   Max: 109
 
 # Offense count: 21
 # Configuration parameters: CountComments, CountAsOne.
 Metrics/ClassLength:
-  Max: 976
+  Max: 1032
 
-# Offense count: 9
+# Offense count: 2
 # Configuration parameters: AllowedMethods, AllowedPatterns.
 Metrics/CyclomaticComplexity:
-  Max: 14
-
-# Offense count: 7
-# Configuration parameters: AllowedMethods, AllowedPatterns.
-Metrics/PerceivedComplexity:
-  Max: 14
+  Max: 8
diff --git a/lib/git/args_builder.rb b/lib/git/args_builder.rb
@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+module Git
+  # Takes a hash of user options and a declarative map and produces
+  # an array of command-line arguments. Also validates that only
+  # supported options are provided based on the map.
+  #
+  # @api private
+  class ArgsBuilder
+    # This hash maps an option type to a lambda that knows how to build the
+    # corresponding command-line argument. This is a scalable dispatch table.
+    ARG_BUILDERS = {
+      boolean: ->(config, value) { value ? config[:flag] : [] },
+
+      valued_equals: ->(config, value) { "#{config[:flag]}=#{value}" if value },
+
+      valued_space: ->(config, value) { [config[:flag], value.to_s] if value },
+
+      repeatable_valued_space: lambda do |config, value|
+        Array(value).flat_map { |v| [config[:flag], v.to_s] }
+      end,
+
+      custom: ->(config, value) { config[:builder].call(value) },
+
+      validate_only: ->(_config, _value) { [] } # Does not build any args
+    }.freeze
+
+    # Main entrypoint to validate options and build arguments
+    def self.build(opts, option_map)
+      validate!(opts, option_map)
+      new(opts, option_map).build
+    end
+
+    # Public validation method that can be called independently
+    def self.validate!(opts, option_map)
+      validate_unsupported_keys!(opts, option_map)
+      validate_configured_options!(opts, option_map)
+    end
+
+    def initialize(opts, option_map)
+      @opts = opts
+      @option_map = option_map
+    end
+
+    def build
+      @option_map.flat_map do |config|
+        type = config[:type]
+        next config[:flag] if type == :static
+
+        key = config[:keys].find { |k| @opts.key?(k) }
+        next [] unless key
+
+        build_arg_for_option(config, @opts[key])
+      end.compact
+    end
+
+    private
+
+    def build_arg_for_option(config, value)
+      builder = ARG_BUILDERS[config[:type]]
+      builder&.call(config, value) || []
+    end
+
+    private_class_method def self.validate_unsupported_keys!(opts, option_map)
+      all_valid_keys = option_map.flat_map { |config| config[:keys] }.compact
+      unsupported_keys = opts.keys - all_valid_keys
+
+      return if unsupported_keys.empty?
+
+      raise ArgumentError, "Unsupported options: #{unsupported_keys.map(&:inspect).join(', ')}"
+    end
+
+    private_class_method def self.validate_configured_options!(opts, option_map)
+      option_map.each do |config|
+        next unless config[:keys] # Skip static flags
+
+        check_for_missing_required_option!(opts, config)
+        validate_option_value!(opts, config)
+      end
+    end
+
+    private_class_method def self.check_for_missing_required_option!(opts, config)
+      return unless config[:required]
+
+      key_provided = config[:keys].any? { |k| opts.key?(k) }
+      return if key_provided
+
+      raise ArgumentError, "Missing required option: #{config[:keys].first}"
+    end
+
+    private_class_method def self.validate_option_value!(opts, config)
+      validator = config[:validator]
+      return unless validator
+
+      user_key = config[:keys].find { |k| opts.key?(k) }
+      return unless user_key # Don't validate if the user didn't provide the option
+
+      return if validator.call(opts[user_key])
+
+      raise ArgumentError, "Invalid value for option: #{user_key}"
+    end
+  end
+end