git_repository: add type signatures and comments

Library/Homebrew/extend/git_repository.rb

-# typed: false
+# typed: strict
 # frozen_string_literal: true
 
 require "utils/git"
 require "utils/popen"
 
+# Extensions to {Pathname} for querying Git repository information.
+# @see Utils::Git
+# @api private
 module GitRepositoryExtension
+  extend T::Sig
+
+  sig { returns(T::Boolean) }
   def git?
     join(".git").exist?
   end
 
+  # Gets the URL of the Git origin remote.
+  sig { returns(T.nilable(String)) }
   def git_origin
     return unless git? && Utils::Git.available?
 
     Utils.popen_read("git", "config", "--get", "remote.origin.url", chdir: self).chomp.presence
   end
 
+  # Sets the URL of the Git origin remote.
+  sig { params(origin: String).returns(T.nilable(T::Boolean)) }
   def git_origin=(origin)
     return unless git? && Utils::Git.available?
 
     safe_system "git", "remote", "set-url", "origin", origin, chdir: self
   end
 
+  # Gets the full commit hash of the HEAD commit.
+  sig { returns(T.nilable(String)) }
   def git_head
     return unless git? && Utils::Git.available?
 
     Utils.popen_read("git", "rev-parse", "--verify", "-q", "HEAD", chdir: self).chomp.presence
   end
 
+  # Gets a short commit hash of the HEAD commit.
+  sig { returns(T.nilable(String)) }
   def git_short_head
     return unless git? && Utils::Git.available?
 
     Utils.popen_read("git", "rev-parse", "--short=4", "--verify", "-q", "HEAD", chdir: self).chomp.presence
   end
 
+  # Gets the relative date of the last commit, e.g. "1 hour ago"
+  sig { returns(T.nilable(String)) }
   def git_last_commit
     return unless git? && Utils::Git.available?
 
     Utils.popen_read("git", "show", "-s", "--format=%cr", "HEAD", chdir: self).chomp.presence
   end
 
+  # Gets the name of the currently checked-out branch, or HEAD if the repository is in a detached HEAD state.
+  sig { returns(T.nilable(String)) }
   def git_branch
     return unless git? && Utils::Git.available?
 
     Utils.popen_read("git", "rev-parse", "--abbrev-ref", "HEAD", chdir: self).chomp.presence
   end
 
+  # Returns the date of the last commit, in YYYY-MM-DD format.
+  sig { returns(T.nilable(String)) }
   def git_last_commit_date
     return unless git? && Utils::Git.available?
 

Library/Homebrew/extend/git_repository.rbi

+# typed: strict
+
+module GitRepositoryExtension
+  include Kernel
+
+  sig { params(args: T.any(String, Pathname)).returns(Pathname) }
+  def join(*args); end
+end

Library/Homebrew/utils/git.rb

@@ -4,6 +4,7 @@
 module Utils
   # Helper functions for querying Git information.
   #
+  # @see GitRepositoryExtension
   # @api private
   module Git
     module_function