1 files changed, 10 insertions, 13 deletions
diff --git a/Library/Homebrew/utils/git.rb b/Library/Homebrew/utils/git.rb
index 43d93b64e..f1113af66 100644
--- a/Library/Homebrew/utils/git.rb
+++ b/Library/Homebrew/utils/git.rb
@@ -16,8 +16,7 @@ module Git
   def last_revision_of_file(repo, file, before_commit: nil)
     relative_file = Pathname(file).relative_path_from(repo)
 
-    commit_hash = last_revision_commit_of_file(repo, file, before_commit: before_commit)
-
+    commit_hash = last_revision_commit_of_file(repo, relative_file, before_commit: before_commit)
     out, = Open3.capture3(
       HOMEBREW_SHIMS_PATH/"scm/git", "-C", repo,
       "show", "#{commit_hash}:#{relative_file}"
@@ -28,8 +27,7 @@ end
 
 module Utils
   def self.git_available?
-    return @git if instance_variable_defined?(:@git)
-    @git = quiet_system HOMEBREW_SHIMS_PATH/"scm/git", "--version"
+    @git ||= quiet_system HOMEBREW_SHIMS_PATH/"scm/git", "--version"
   end
 
   def self.git_path
@@ -50,21 +48,20 @@ module Utils
     return if git_available?
 
     # we cannot install brewed git if homebrew/core is unavailable.
-    raise "Git is unavailable" unless CoreTap.instance.installed?
-
-    begin
-      oh1 "Installing git"
-      safe_system HOMEBREW_BREW_FILE, "install", "git"
-    rescue
-      raise "Git is unavailable"
+    if CoreTap.instance.installed?
+      begin
+        oh1 "Installing git"
+        safe_system HOMEBREW_BREW_FILE, "install", "git"
+      rescue
+        raise "Git is unavailable"
+      end
     end
 
-    clear_git_available_cache
     raise "Git is unavailable" unless git_available?
   end
 
   def self.clear_git_available_cache
-    remove_instance_variable(:@git) if instance_variable_defined?(:@git)
+    @git = nil
     @git_path = nil
     @git_version = nil
   end