add Tap#formula_file?

Return true if given path would present a Formula file in this Tap.
Accepts both absolute path and relative path (relative to this Tap's path)

It offer an abstraction such that caller would not need to worry about
low level file system in the tap.

It will be used in `brew pull` and `brew update`.

Closes Homebrew/homebrew#49191.

Signed-off-by: Xu Cheng <xucheng@me.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index 712348d60..08e85688d 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -247,6 +247,15 @@ class Tap
     end
   end
 
+  # return true if given path would present a {Formula} file in this {Tap}.
+  # accepts both absolute path and relative path (relative to this {Tap}'s path)
+  # @private
+  def formula_file?(file)
+    file = Pathname.new(file) unless file.is_a? Pathname
+    file = file.expand_path(path)
+    file.extname == ".rb" && file.parent == formula_dir
+  end
+
   # an array of all {Formula} names of this {Tap}.
   def formula_names
     @formula_names ||= formula_files.map { |f| formula_file_to_name(f) }