Add RealpathCache and make require_relative to require via realpath

Author: ojab

lib/bootsnap/load_path_cache.rb

@@ -21,12 +21,14 @@ module LoadPathCache
     CACHED_EXTENSIONS = DLEXT2 ? [DOT_RB, DLEXT, DLEXT2] : [DOT_RB, DLEXT]
 
     class << self
-      attr_reader :load_path_cache, :autoload_paths_cache, :loaded_features_index
+      attr_reader :load_path_cache, :autoload_paths_cache,
+                  :loaded_features_index, :realpath_cache
 
       def setup(cache_path:, development_mode:, active_support: true)
         store = Store.new(cache_path)
 
         @loaded_features_index = LoadedFeaturesIndex.new
+        @realpath_cache = RealpathCache.new
 
         @load_path_cache = Cache.new(store, $LOAD_PATH, development_mode: development_mode)
         require_relative 'load_path_cache/core_ext/kernel_require'
@@ -53,3 +55,4 @@ def setup(cache_path:, development_mode:, active_support: true)
 require_relative 'load_path_cache/store'
 require_relative 'load_path_cache/change_observer'
 require_relative 'load_path_cache/loaded_features_index'
+require_relative 'load_path_cache/realpath_cache'

lib/bootsnap/load_path_cache/core_ext/kernel_require.rb

@@ -34,6 +34,14 @@ def require(path)
     require_with_bootsnap_lfi(path)
   end
 
+  alias_method :require_relative_without_bootsnap, :require_relative
+  def require_relative(path)
+    realpath = Bootsnap::LoadPathCache.realpath_cache.call(
+      caller_locations.first.absolute_path, path
+    )
+    require(realpath)
+  end
+
   alias_method :load_without_bootsnap, :load
   def load(path, wrap = false)
     if resolved = Bootsnap::LoadPathCache.load_path_cache.find(path)
@@ -76,6 +84,14 @@ def require(path)
     require_with_bootsnap_lfi(path)
   end
 
+  alias_method :require_relative_without_bootsnap, :require_relative
+  def require_relative(path)
+    realpath = Bootsnap::LoadPathCache.realpath_cache.call(
+      caller_locations.first.absolute_path, path
+    )
+    require(realpath)
+  end
+
   alias_method :load_without_bootsnap, :load
   def load(path, wrap = false)
     if resolved = Bootsnap::LoadPathCache.load_path_cache.find(path)

lib/bootsnap/load_path_cache/realpath_cache.rb

@@ -0,0 +1,22 @@
+module Bootsnap
+  module LoadPathCache
+    class RealpathCache
+      def initialize
+        @cache = Hash.new { |h, k| h[k] = realpath(*k) }
+      end
+
+      def call(*key)
+        @cache[key]
+      end
+
+      private
+
+      def realpath(caller_location, path)
+        base = File.dirname(caller_location)
+        file = File.expand_path(path, base)
+        dir = File.dirname(file)
+        File.join(File.realpath(dir), File.basename(file))
+      end
+    end
+  end
+end