Fix Style/OneClassPerFile offenses

Collapse the 14 reopenings of MultiJSONBenchmark in benchmark.rb into
a single class body, fold the second module MultiJSON block in
options_cache.rb into the first, and extract the deprecated MultiJson
constant shim from lib/multi_json.rb into
lib/multi_json/legacy_constant.rb, required after multi_json/deprecated
so the forwarder snapshot still sees the complete public API.

Author: sferik

benchmark.rb

@@ -45,9 +45,7 @@ def verify_preference(adapters, measurements)
       verifier.valid? ? 0 : 1
     end
   end
-end
 
-class MultiJSONBenchmark
   # Command-line option parsing for the benchmark script.
   class CLI
     QUICK_OPTIONS = {
@@ -139,9 +137,7 @@ def validate_samples!(value)
       raise OptionParser::InvalidArgument, "--samples must be > 0" unless value.positive?
     end
   end
-end
 
-class MultiJSONBenchmark
   # Resolves benchmarkable adapters from the current Ruby environment.
   class AdapterLoader
     def load(selected = nil)
@@ -162,9 +158,7 @@ def load_entry(name)
       nil
     end
   end
-end
 
-class MultiJSONBenchmark
   # Builds the benchmark payload matrix across shapes and sizes.
   class PayloadCatalog
     CASES = [
@@ -206,9 +200,7 @@ def payload_case(shape, bucket, object)
       )
     end
   end
-end
 
-class MultiJSONBenchmark
   # Builds flat scalar and array-heavy payloads.
   class ScalarPayloadFactory
     def flat_scalars(count)
@@ -256,9 +248,7 @@ def token(prefix, index, width)
       "#{prefix}_#{index.to_s(36).rjust(width, "0")}"
     end
   end
-end
 
-class MultiJSONBenchmark
   # Builds nested object-heavy record payloads.
   class RecordPayloadFactory
     COUNTRIES = %w[US DE BR JP IN AU GB CA].freeze
@@ -341,9 +331,7 @@ def token(prefix, index, width)
       "#{prefix}_#{index.to_s(36).rjust(width, "0")}"
     end
   end
-end
 
-class MultiJSONBenchmark
   # Runs the benchmark matrix across adapters, payloads, and operations.
   class Runner
     OPERATIONS = %i[parse generate].freeze
@@ -394,9 +382,7 @@ def prime_adapter!(adapter, payload)
       adapter.dump(payload.object)
     end
   end
-end
 
-class MultiJSONBenchmark
   # Measures throughput for a single adapter/payload/operation combination.
   class Sampler
     def initialize(options)
@@ -462,9 +448,7 @@ def with_gc_disabled
       GC.enable unless already_disabled
     end
   end
-end
 
-class MultiJSONBenchmark
   # Prints the benchmark summary and detailed result tables.
   class Reporter
     SUMMARY_HEADERS = ["adapter", "parse score", "generate score", "overall score", "wins"].freeze
@@ -513,9 +497,7 @@ def print_details
       )
     end
   end
-end
 
-class MultiJSONBenchmark
   # Asserts MultiJSON::AdapterSelector::ADAPTERS matches the overall
   # benchmark throughput ranking.
   #
@@ -597,9 +579,7 @@ def tolerance_pct
       (TOLERANCE * 100).to_i
     end
   end
-end
 
-class MultiJSONBenchmark
   # Computes overall adapter scores and benchmark wins.
   class Summary
     def initialize(adapters, measurements)
@@ -668,9 +648,7 @@ def normalized_ratio(value, peak)
       value / [peak, MultiJSONBenchmark::EPSILON].max
     end
   end
-end
 
-class MultiJSONBenchmark
   # Builds the per-benchmark detail table rows.
   class Details
     def initialize(adapters, measurements)
@@ -734,9 +712,7 @@ def grouped_measurements
       @grouped_measurements ||= measurements.group_by { |measurement| [measurement.payload.label, measurement.operation] }
     end
   end
-end
 
-class MultiJSONBenchmark
   # Renders plain-text and markdown tables for benchmark output.
   class TableRenderer
     def initialize(format:)
@@ -792,9 +768,7 @@ def align_cell(text, width, alignment)
       (alignment == :right) ? text.rjust(width) : text.ljust(width)
     end
   end
-end
 
-class MultiJSONBenchmark
   # Shared numeric and display formatting helpers for benchmark output.
   class Formatter
     class << self

lib/multi_json.rb

@@ -267,54 +267,4 @@ def with_adapter(new_adapter, &)
 end
 
 require_relative "multi_json/deprecated"
-
-# Backward-compatible alias for the legacy ``MultiJson`` constant name
-#
-# Downstream code that still writes ``MultiJson.parse(...)`` or
-# ``rescue MultiJson::ParseError`` continues to work, but emits a
-# one-time deprecation warning pointing at ``MultiJSON``. Each public
-# method on {MultiJSON} gets an explicit forwarder defined on this
-# module, and constant access resolves via {.const_missing}, so both
-# dotted calls and ``::`` constant lookups (including rescue clauses)
-# route through the canonical module.
-#
-# @api public
-# @deprecated Use {MultiJSON} (all-caps) instead. Will be removed in v2.0.
-module MultiJson
-  # Forward every public method MultiJSON exposes through an explicit
-  # singleton method on the legacy MultiJson module, so callers that
-  # capture the method as a Method object (``MultiJson.method(:load)``)
-  # find this forwarder instead of falling back to inherited methods like
-  # ``Kernel#load``. The earlier ``method_missing``-based shim left
-  # ``MultiJson.method(:load)`` resolving to ``Kernel#load`` (because
-  # ``Module#method`` doesn't consult ``method_missing``) and broke
-  # libraries (Sawyer, Octokit, Danger) that capture decoders as Method
-  # objects. Forwarding eagerly fixes the capture path while preserving
-  # the one-time deprecation warning each call emits.
-  (::MultiJSON.public_methods - ::Module.public_methods).each do |forwarded|
-    define_singleton_method(forwarded) do |*args, **kwargs, &block|
-      ::MultiJSON.warn_deprecation_once(:multi_json_constant,
-        "The MultiJson constant is deprecated and will be removed in v2.0. Use MultiJSON instead.")
-      ::MultiJSON.public_send(forwarded, *args, **kwargs, &block)
-    end
-  end
-
-  class << self
-    # Resolve missing constants to their {MultiJSON} counterparts
-    #
-    # Enables ``rescue MultiJson::ParseError`` and
-    # ``MultiJson::Adapters::Oj`` to keep working during the
-    # deprecation cycle.
-    #
-    # @api public
-    # @param name [Symbol] constant name
-    # @return [Object] the resolved constant from {MultiJSON}
-    # @example
-    #   MultiJson::ParseError  # returns MultiJSON::ParseError
-    def const_missing(name)
-      ::MultiJSON.warn_deprecation_once(:multi_json_constant,
-        "The MultiJson constant is deprecated and will be removed in v2.0. Use MultiJSON instead.")
-      ::MultiJSON.const_get(name)
-    end
-  end
-end
+require_relative "multi_json/legacy_constant"

lib/multi_json/legacy_constant.rb

@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+# Backward-compatible alias for the legacy ``MultiJson`` constant name
+#
+# Downstream code that still writes ``MultiJson.parse(...)`` or
+# ``rescue MultiJson::ParseError`` continues to work, but emits a
+# one-time deprecation warning pointing at ``MultiJSON``. Each public
+# method on {MultiJSON} gets an explicit forwarder defined on this
+# module, and constant access resolves via {.const_missing}, so both
+# dotted calls and ``::`` constant lookups (including rescue clauses)
+# route through the canonical module.
+#
+# This file is loaded last by the ``multi_json`` entry point so the
+# forwarder snapshot below sees the complete {MultiJSON} public API,
+# including the deprecated aliases defined in ``deprecated.rb``.
+#
+# @api public
+# @deprecated Use {MultiJSON} (all-caps) instead. Will be removed in v2.0.
+module MultiJson
+  # Forward every public method MultiJSON exposes through an explicit
+  # singleton method on the legacy MultiJson module, so callers that
+  # capture the method as a Method object (``MultiJson.method(:load)``)
+  # find this forwarder instead of falling back to inherited methods like
+  # ``Kernel#load``. The earlier ``method_missing``-based shim left
+  # ``MultiJson.method(:load)`` resolving to ``Kernel#load`` (because
+  # ``Module#method`` doesn't consult ``method_missing``) and broke
+  # libraries (Sawyer, Octokit, Danger) that capture decoders as Method
+  # objects. Forwarding eagerly fixes the capture path while preserving
+  # the one-time deprecation warning each call emits.
+  (::MultiJSON.public_methods - ::Module.public_methods).each do |forwarded|
+    define_singleton_method(forwarded) do |*args, **kwargs, &block|
+      ::MultiJSON.warn_deprecation_once(:multi_json_constant,
+        "The MultiJson constant is deprecated and will be removed in v2.0. Use MultiJSON instead.")
+      ::MultiJSON.public_send(forwarded, *args, **kwargs, &block)
+    end
+  end
+
+  class << self
+    # Resolve missing constants to their {MultiJSON} counterparts
+    #
+    # Enables ``rescue MultiJson::ParseError`` and
+    # ``MultiJson::Adapters::Oj`` to keep working during the
+    # deprecation cycle.
+    #
+    # @api public
+    # @param name [Symbol] constant name
+    # @return [Object] the resolved constant from {MultiJSON}
+    # @example
+    #   MultiJson::ParseError  # returns MultiJSON::ParseError
+    def const_missing(name)
+      ::MultiJSON.warn_deprecation_once(:multi_json_constant,
+        "The MultiJson constant is deprecated and will be removed in v2.0. Use MultiJSON instead.")
+      ::MultiJSON.const_get(name)
+    end
+  end
+end

lib/multi_json/options_cache.rb

@@ -17,6 +17,13 @@ module OptionsCache
     # via {.max_cache_size=}.
     DEFAULT_MAX_CACHE_SIZE = 1000
 
+    # Dynamic require path so MRI (mutex_store) and JRuby
+    # (concurrent_store) execute the same physical line, avoiding a
+    # dead-branch ``require_relative`` that would otherwise drop
+    # JRuby's line coverage below 100%.
+    BACKENDS = {"jruby" => "concurrent_store"}.freeze
+    private_constant :BACKENDS
+
     class << self
       # Get the dump options cache
       #
@@ -71,16 +78,5 @@ def reset
   end
 end
 
-module MultiJSON
-  module OptionsCache
-    # Dynamic require path so MRI (mutex_store) and JRuby
-    # (concurrent_store) execute the same physical line, avoiding a
-    # dead-branch ``require_relative`` that would otherwise drop
-    # JRuby's line coverage below 100%.
-    BACKENDS = {"jruby" => "concurrent_store"}.freeze
-    private_constant :BACKENDS
-  end
-end
-
 require_relative "options_cache/#{MultiJSON::OptionsCache.send(:const_get, :BACKENDS).fetch(RUBY_ENGINE, "mutex_store")}"
 MultiJSON::OptionsCache.reset