From b12623f4eb9666003a8bb915a73ee6d621c81465 Mon Sep 17 00:00:00 2001
From: Markus Reiter <me@reitermark.us>
Date: Fri, 31 May 2019 20:37:57 +0200
Subject: [PATCH 1/2] =?UTF-8?q?Don't=20redownload=20=E2=80=9Clatest?=
 =?UTF-8?q?=E2=80=9D=20casks=20unnecessarily.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 Library/Homebrew/cask/download.rb     | 2 +-
 Library/Homebrew/download_strategy.rb | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/cask/download.rb b/Library/Homebrew/cask/download.rb
index eb3a444bc4e9b..4bd4e4426a77d 100644
--- a/Library/Homebrew/cask/download.rb
+++ b/Library/Homebrew/cask/download.rb
@@ -35,7 +35,7 @@ def downloader
     attr_accessor :downloaded_path
 
     def clear_cache
-      downloader.clear_cache if force || cask.version.latest?
+      downloader.clear_cache if force
     end
 
     def fetch
diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 5afb8c13ede92..924c17f117456 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -296,6 +296,8 @@ def fetch
 
       fresh = if cached_location.exist? && url_time
         url_time <= cached_location.mtime
+      elsif version.respond_to?(:latest?)
+        !version.latest?
       else
         true
       end

From 17f6d19b9c178b2d54abcea67c5eba22b619588f Mon Sep 17 00:00:00 2001
From: Markus Reiter <me@reitermark.us>
Date: Fri, 31 May 2019 20:38:28 +0200
Subject: [PATCH 2/2] Add `Cask#install_time` method.

---
 Library/Homebrew/cask/cask.rb     | 7 +++++++
 Library/Homebrew/cask/metadata.rb | 8 ++------
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/Library/Homebrew/cask/cask.rb b/Library/Homebrew/cask/cask.rb
index 23d20dcc7889f..aef26e8b6f39f 100644
--- a/Library/Homebrew/cask/cask.rb
+++ b/Library/Homebrew/cask/cask.rb
@@ -80,6 +80,13 @@ def installed?
       !versions.empty?
     end
 
+    def install_time
+      _, time = timestamped_versions.last
+      return unless time
+
+      Time.strptime(time, Metadata::TIMESTAMP_FORMAT)
+    end
+
     def installed_caskfile
       installed_version = timestamped_versions.last
       metadata_master_container_path.join(*installed_version, "Casks", "#{token}.rb")
diff --git a/Library/Homebrew/cask/metadata.rb b/Library/Homebrew/cask/metadata.rb
index 9a47567e9f570..b15fbdda394aa 100644
--- a/Library/Homebrew/cask/metadata.rb
+++ b/Library/Homebrew/cask/metadata.rb
@@ -3,6 +3,7 @@
 module Cask
   module Metadata
     METADATA_SUBDIR = ".metadata"
+    TIMESTAMP_FORMAT = "%Y%m%d%H%M%S.%L"
 
     def metadata_master_container_path
       @metadata_master_container_path ||= caskroom_path.join(METADATA_SUBDIR)
@@ -58,12 +59,7 @@ def metadata_subdir(leaf, version: self.version, timestamp: :latest, create: fal
     private
 
     def new_timestamp(time = Time.now)
-      time = time.utc
-
-      timestamp = time.strftime("%Y%m%d%H%M%S")
-      fraction = format("%.3f", time.to_f - time.to_i)[1..-1]
-
-      timestamp.concat(fraction)
+      time.utc.strftime(TIMESTAMP_FORMAT)
     end
   end
 end