Sources now retained in Caches/Homebrew/Sources

Full path is ~/Library/Caches/Homebrew/Sources

This creates a brand new directory for each build, but leaves previous.

Library/Homebrew/mksource.rb

@@ -1,84 +0,0 @@
-# typed: false
-# frozen_string_literal: true
-
-# Performs {Formula#mktemp}'s functionality, and tracks the results.
-# Each instance is only intended to be used once.
-class Mksource
-  extend T::Sig
-
-  include FileUtils
-
-  # Path to the tmpdir used in this run, as a {Pathname}.
-  attr_reader :tmpdir
-
-  def initialize(prefix, opts = {})
-    @prefix = prefix
-    @retain = opts[:retain]
-    @quiet = false
-  end
-
-  # Instructs this {Mksource} to retain the staged files.
-  sig { void }
-  def retain!
-    @retain = true
-  end
-
-  # True if the staged temporary files should be retained.
-  def retain?
-    @retain
-  end
-
-  # Instructs this Mksource to not emit messages when retention is triggered.
-  sig { void }
-  def quiet!
-    @quiet = true
-  end
-
-  sig { returns(String) }
-  def to_s
-    "[Mksource: #{tmpdir} retain=#{@retain} quiet=#{@quiet}]"
-  end
-
-  def run
-    @tmpdir = Pathname.new(Dir.mktmpdir("#{@prefix.tr "@", "AT"}-", HOMEBREW_TEMP))
-
-    # Make sure files inside the temporary directory have the same group as the
-    # brew instance.
-    #
-    # Reference from `man 2 open`
-    # > When a new file is created, it is given the group of the directory which
-    # contains it.
-    group_id = if HOMEBREW_BREW_FILE.grpowned?
-      HOMEBREW_BREW_FILE.stat.gid
-    else
-      Process.gid
-    end
-    begin
-      chown(nil, group_id, tmpdir)
-    rescue Errno::EPERM
-      opoo "Failed setting group \"#{Etc.getgrgid(group_id).name}\" on #{tmpdir}"
-    end
-
-    begin
-      Dir.chdir(tmpdir) { yield self }
-    ensure
-      ignore_interrupts { chmod_rm_rf(tmpdir) } unless retain?
-    end
-  ensure
-    ohai "Temporary files retained at:", @tmpdir.to_s if retain? && !@tmpdir.nil? && !@quiet
-  end
-
-  private
-
-  def chmod_rm_rf(path)
-    if path.directory? && !path.symlink?
-      chmod("u+rw", path) if path.owned? # Need permissions in order to see the contents
-      path.children.each { |child| chmod_rm_rf(child) }
-      rmdir(path)
-    else
-      rm_f(path)
-    end
-  rescue
-    nil # Just skip this directory.
-  end
-end

Library/Homebrew/mktemp.rb

@@ -13,7 +13,8 @@ class Mktemp
 
   def initialize(prefix, opts = {})
     @prefix = prefix
-    @retain = opts[:retain]
+    @retain_in_sources = opts[:retain_in_sources]
+    @retain = opts[:retain] || @retain_in_sources
     @quiet = false
   end
 
@@ -40,7 +41,13 @@ class Mktemp
   end
 
   def run
-    @tmpdir = Pathname.new(Dir.mktmpdir("#{@prefix.tr "@", "AT"}-", HOMEBREW_TEMP))
+    if @retain_in_sources
+      root = "#{HOMEBREW_CACHE}/Sources"
+      FileUtils.mkdir_p root
+    else
+      root = HOMEBREW_TEMP
+    end
+    @tmpdir = Pathname.new(Dir.mktmpdir("#{@prefix.tr "@", "AT"}-", root))
 
     # Make sure files inside the temporary directory have the same group as the
     # brew instance.

Library/Homebrew/resource.rb

@@ -5,7 +5,6 @@ require "download_strategy"
 require "checksum"
 require "version"
 require "mktemp"
-require "mksource"
 require "livecheck"
 require "extend/on_system"
 
@@ -237,7 +236,7 @@ class Resource
   protected
 
   def stage_resource(prefix, debug_symbols: false, &block)
-    debug_symbols ? Mksource.new(prefix).run(&block) : Mktemp.new(prefix).run(&block)
+    Mktemp.new(prefix, retain_in_sources: debug_symbols).run(&block)
   end
 
   private