brew tap: allow tapping non-GitHub repositories.

`brew tap` restricts users to GitHub and checks for private repos. I
created `brew any-tap` to support a wider variety of taps.

With very small changes (and no extra flags!), this change allows users
to use `brew tap` with GitHub as they always have or add one extra
argument and tap any repository of any type from anywhere.

    brew tap user/name              # Same as it ever was
    brew tap user/name URL          # Tap URL, whatever it happens to be

Closes Homebrew/homebrew#40326.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

2 files changed, 25 insertions, 14 deletions

diff --git a/Library/Homebrew/cmd/tap.rb b/Library/Homebrew/cmd/tap.rb
index 8b38b8bb0..14542f1c5 100644
--- a/Library/Homebrew/cmd/tap.rb
+++ b/Library/Homebrew/cmd/tap.rb
@@ -7,11 +7,13 @@ module Homebrew
     elsif ARGV.first == "--repair"
       migrate_taps :force => true
     else
-      opoo "Already tapped!" unless install_tap(*tap_args)
+      user, repo = tap_args
+      clone_target = ARGV.named[1]
+      opoo "Already tapped!" unless install_tap(user, repo, clone_target)
     end
   end
 
-  def install_tap user, repo
+  def install_tap user, repo, clone_target=nil
     # we special case homebrew so users don't have to shift in a terminal
     repouser = if user == "homebrew" then "Homebrew" else user end
     user = "homebrew" if user == "Homebrew"
@@ -20,7 +22,11 @@ module Homebrew
     tapd = HOMEBREW_LIBRARY/"Taps/#{user.downcase}/homebrew-#{repo.downcase}"
     return false if tapd.directory?
     ohai "Tapping #{repouser}/#{repo}"
-    args = %W[clone https://github.com/#{repouser}/homebrew-#{repo} #{tapd}]
+    if clone_target
+      args = %W[clone #{clone_target} #{tapd}]
+    else
+      args = %W[clone https://github.com/#{repouser}/homebrew-#{repo} #{tapd}]
+    end
     args << "--depth=1" unless ARGV.include?("--full")
     safe_system "git", *args
 
@@ -28,14 +34,15 @@ module Homebrew
     tapd.find_formula { |file| files << file }
     puts "Tapped #{files.length} formula#{plural(files.length, 'e')} (#{tapd.abv})"
 
-    if private_tap?(repouser, repo) then puts <<-EOS.undent
-      It looks like you tapped a private repository. To avoid entering your
-      credentials each time you update, you can use git HTTP credential caching
-      or issue the following command:
+    if check_private?(clone_target, repouser, repo)
+      puts <<-EOS.undent
+        It looks like you tapped a private repository. To avoid entering your
+        credentials each time you update, you can use git HTTP credential
+        caching or issue the following command:
 
-        cd #{tapd}
-        git remote set-url origin git@github.com:#{repouser}/homebrew-#{repo}.git
-      EOS
+          cd #{tapd}
+          git remote set-url origin git@github.com:#{repouser}/homebrew-#{repo}.git
+        EOS
     end
 
     true
@@ -76,4 +83,8 @@ module Homebrew
   rescue GitHub::Error
     false
   end
+
+  def check_private?(clone_target, user, repo)
+    not clone_target && private_tap?(user, repo)
+  end
 end
diff --git a/Library/Homebrew/cmd/untap.rb b/Library/Homebrew/cmd/untap.rb
index 37ed2a3f1..937439e9d 100644
--- a/Library/Homebrew/cmd/untap.rb
+++ b/Library/Homebrew/cmd/untap.rb
@@ -7,10 +7,10 @@ module Homebrew
     ARGV.each do |tapname|
       user, repo = tap_args(tapname)
 
-      # we consistently downcase in tap to ensure we are not bitten by case-insensive
-      # filesystem issues. Which is the default on mac. The problem being the
-      # filesystem cares, but our regexps don't. So unless we resolve *every* path
-      # we will get bitten.
+      # We consistently downcase in tap to ensure we are not bitten by
+      # case-insensitive filesystem issues, which is the default on mac. The
+      # problem being the filesystem cares, but our regexps don't. So unless we
+      # resolve *every* path we will get bitten.
       user.downcase!
       repo.downcase!