From 901c0b728d0011e0384f78d7a7d640dda980bc83 Mon Sep 17 00:00:00 2001
From: Jean Boussier <jean.boussier@gmail.com>
Date: Tue, 31 May 2022 16:00:43 +0200
Subject: [PATCH] Add Bootsnap.unload_cache!

---
 CHANGELOG.md                                     |  3 +++
 lib/bootsnap.rb                                  |  4 ++++
 lib/bootsnap/load_path_cache.rb                  | 16 +++++++++++++++-
 .../load_path_cache/core_ext/kernel_require.rb   |  2 ++
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dc188568..30f7f600 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@
 
   People still using the classic autoloader might want to stick to `bootsnap 1.12`.
 
+* Add `Bootsnap.unload_cache!`. Applications can call it at the end of their boot sequence when they know
+  no more code will be loaded to reclaim a bit of memory.
+
 # 1.12.0
 
 * `bootsnap precompile` CLI will now also precompile `Rakefile` and `.rake` files.
diff --git a/lib/bootsnap.rb b/lib/bootsnap.rb
index 5aee9629..d5490f3a 100644
--- a/lib/bootsnap.rb
+++ b/lib/bootsnap.rb
@@ -76,6 +76,10 @@ def setup(
       )
     end
 
+    def self.unload_cache!
+      LoadPathCache.unload!
+    end
+
     def iseq_cache_supported?
       return @iseq_cache_supported if defined? @iseq_cache_supported
 
diff --git a/lib/bootsnap/load_path_cache.rb b/lib/bootsnap/load_path_cache.rb
index 05e9d30f..30ced18f 100644
--- a/lib/bootsnap/load_path_cache.rb
+++ b/lib/bootsnap/load_path_cache.rb
@@ -21,8 +21,12 @@ module LoadPathCache
 
     CACHED_EXTENSIONS = DLEXT2 ? [DOT_RB, DLEXT, DLEXT2] : [DOT_RB, DLEXT]
 
+    @enabled = false
+
     class << self
-      attr_reader(:load_path_cache, :loaded_features_index)
+      attr_reader(:load_path_cache, :loaded_features_index, :enabled)
+      alias_method :enabled?, :enabled
+      remove_method(:enabled)
 
       def setup(cache_path:, development_mode:)
         unless supported?
@@ -35,10 +39,20 @@ def setup(cache_path:, development_mode:)
         @loaded_features_index = LoadedFeaturesIndex.new
 
         @load_path_cache = Cache.new(store, $LOAD_PATH, development_mode: development_mode)
+        @enabled = true
         require_relative("load_path_cache/core_ext/kernel_require")
         require_relative("load_path_cache/core_ext/loaded_features")
       end
 
+      def unload!
+        @enabled = false
+        @loaded_features_index = nil
+        @realpath_cache = nil
+        @load_path_cache = nil
+        ChangeObserver.unregister($LOAD_PATH)
+        ::Kernel.alias_method(:require_relative, :require_relative_without_bootsnap)
+      end
+
       def supported?
         RUBY_ENGINE == "ruby" &&
           RUBY_PLATFORM =~ /darwin|linux|bsd|mswin|mingw|cygwin/
diff --git a/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb b/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb
index 8785f446..034a1ff5 100644
--- a/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb
+++ b/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb
@@ -6,6 +6,8 @@ module Kernel
   alias_method(:require_without_bootsnap, :require)
 
   def require(path)
+    return require_without_bootsnap(path) unless Bootsnap::LoadPathCache.enabled?
+
     string_path = Bootsnap.rb_get_path(path)
     return false if Bootsnap::LoadPathCache.loaded_features_index.key?(string_path)