Reset Bootsnap after installing gems

Library/Homebrew/cleanup.rb

@@ -558,7 +558,7 @@ module Homebrew
       return unless bootsnap.directory?
 
       bootsnap.each_child do |subdir|
-        cleanup_path(subdir) { FileUtils.rm_r(subdir) } if subdir.basename.to_s != Homebrew.bootsnap_key
+        cleanup_path(subdir) { FileUtils.rm_r(subdir) } if subdir.basename.to_s != Homebrew::Bootsnap.key
       end
     end
 

Library/Homebrew/standalone/init.rbi

@@ -0,0 +1,3 @@
+# typed: strict
+
+HOMEBREW_USING_PORTABLE_RUBY = T.let(false, T::Boolean)

Library/Homebrew/startup/bootsnap.rb

@@ -1,13 +1,10 @@
 # typed: true
 # frozen_string_literal: true
 
-homebrew_bootsnap_enabled = HOMEBREW_USING_PORTABLE_RUBY &&
-                            ENV["HOMEBREW_NO_BOOTSNAP"].nil? &&
-                            !ENV["HOMEBREW_BOOTSNAP"].nil?
-
 module Homebrew
-  def self.bootsnap_key
-    @bootsnap_key ||= begin
+  module Bootsnap
+    def self.key
+      @key ||= begin
         require "digest/sha2"
 
         checksum = Digest::SHA256.new
@@ -18,29 +15,53 @@ module Homebrew
         checksum.hexdigest
       end
     end
-end
-
-if homebrew_bootsnap_enabled
-  require "bootsnap"
 
+    private_class_method def self.cache_dir
       cache = ENV.fetch("HOMEBREW_CACHE", nil) || ENV.fetch("HOMEBREW_DEFAULT_CACHE", nil)
       raise "Needs HOMEBREW_CACHE or HOMEBREW_DEFAULT_CACHE!" if cache.nil? || cache.empty?
 
-  cache = File.join(cache, "bootsnap", Homebrew.bootsnap_key)
+      File.join(cache, "bootsnap", key)
+    end
 
+    private_class_method def self.ignore_directories
       # We never do `require "vendor/bundle/ruby/..."` or `require "vendor/portable-ruby/..."`,
       # so let's slim the cache a bit by excluding them.
       # Note that gems within `bundle/ruby` will still be cached - these are when directory walking down from above.
-  ignore_directories = [
+      [
         (HOMEBREW_LIBRARY_PATH/"vendor/bundle/ruby").to_s,
         (HOMEBREW_LIBRARY_PATH/"vendor/portable-ruby").to_s,
       ]
+    end
 
-  Bootsnap.setup(
-    cache_dir:          cache,
+    private_class_method def self.enabled?
+      HOMEBREW_USING_PORTABLE_RUBY && ENV["HOMEBREW_NO_BOOTSNAP"].nil? && !ENV["HOMEBREW_BOOTSNAP"].nil?
+    end
+
+    def self.load!(compile_cache: true)
+      return unless enabled?
+
+      require "bootsnap"
+
+      ::Bootsnap.setup(
+        cache_dir:,
         ignore_directories:,
         load_path_cache:    true,
-    compile_cache_iseq: true,
-    compile_cache_yaml: true,
+        compile_cache_iseq: compile_cache,
+        compile_cache_yaml: compile_cache,
+        compile_cache_json: compile_cache,
       )
     end
+
+    def self.reset!
+      return unless enabled?
+
+      ::Bootsnap.unload_cache!
+      @key = nil
+
+      # The compile cache doesn't get unloaded so we don't need to load it again!
+      load!(compile_cache: false)
+    end
+  end
+end
+
+Homebrew::Bootsnap.load!

Library/Homebrew/startup/bootsnap.rbi

@@ -1,8 +1,25 @@
 # typed: strict
 
 module Homebrew
+  module Bootsnap
     sig { returns(String) }
-  def self.bootsnap_key; end
+    def self.key; end
+
+    sig { returns(String) }
+    private_class_method def self.cache_dir; end
+
+    sig { returns(T::Array[String]) }
+    private_class_method def self.ignore_directories; end
+
+    sig { returns(T::Boolean) }
+    private_class_method def self.enabled?; end
+
+    sig { params(compile_cache: T::Boolean).void }
+    def self.load!(compile_cache: true); end
+
+    sig { void }
+    def self.reset!; end
+  end
 end
 
 module Bootsnap
@@ -29,5 +46,9 @@ module Bootsnap
     compile_cache_iseq: true,
     compile_cache_yaml: true,
     compile_cache_json: true
-  ); end
+  )
+  end
+
+  sig { void }
+  def self.unload_cache!; end
 end

Library/Homebrew/utils/gems.rb

@@ -303,6 +303,7 @@ module Homebrew
           exec bundle, "install", out: :err
         end)
         if $CHILD_STATUS.success?
+          Homebrew::Bootsnap.reset! if defined?(Homebrew::Bootsnap) # Gem install can run before Bootsnap loads
           true
         else
           message = <<~EOS