Rake executes file task when prerequisites have older timestamp

When a file task depends on some non-file task indirectly,
Rake executes the file task even if its immediate prerequisite files have older timestamp.

It looks like the behavior changed at 12.1.0.

Example

require "rake/clean"

CLEAN.include("config.yml", "component")

task "setup" do
  puts Rake::VERSION
  touch "config.yml" unless File.exist?("config.yml")
end

file "config.yml" => "setup"

file "component" => "config.yml" do |t|
  puts "[config.yml] #{File.mtime(t.prerequisites[0])}"
  puts "[component]  #{File.exist?(t.name) && File.mtime(t.name)}"
  sleep 1
  touch t.name
end

Based on the above Rakefile, clean up and create the "component" first.

$ rake clean && rake component

The next rake component results in different behavior as follows.
On 12.0.0:

$ rake component --trace
(in /path/to/Rakefile-directory)
** Invoke component (first_time, not_needed)
** Invoke config.yml (first_time)
** Invoke setup (first_time)
** Execute setup
12.0.0
** Execute config.yml

On 12.1.0:

$ rake component --trace
(in /path/to/Rakefile-directory)
** Invoke component (first_time)
** Invoke config.yml (first_time)
** Invoke setup (first_time)
** Execute setup
12.1.0
** Execute config.yml
** Execute component
[config.yml] 2018-01-01 15:13:19 +0900
[component]  2018-01-01 15:13:20 +0900
touch component

Rakefile の例で問題を再現し、影響を受ける動作と 12.0 の間で --trace の出力を比較します。まず、file-task の前提条件とタイムスタンプがどのように評価されるかを追跡します。rake component が直接の前提ファイルが古い場合に file task を実行しなくなれば完了です。