remove Pathname#find_formula

Closes Homebrew/homebrew#40486.

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

Library/Homebrew/extend/pathname.rb

@@ -327,17 +327,6 @@ class Pathname
     quiet_system "/usr/bin/install-info", "--delete", "--quiet", to_s, "#{dirname}/dir"
   end
 
-  def find_formula
-    [join("Formula"), join("HomebrewFormula"), self].each do |d|
-      if d.exist?
-        d.children.each do |pn|
-          yield pn if pn.extname == ".rb"
-        end
-        break
-      end
-    end
-  end
-
   # Writes an exec script in this folder for each target pathname
   def write_exec_script *targets
     targets.flatten!

Library/Homebrew/formula.rb

@@ -9,6 +9,7 @@ require 'formulary'
 require 'software_spec'
 require 'install_renamed'
 require 'pkg_version'
+require 'tap'
 
 # A formula provides instructions and metadata for Homebrew to install a piece
 # of software. Every Homebrew formula is a {Formula}.
@@ -627,14 +628,7 @@ class Formula
 
   # an array of all tap {Formula} names
   def self.tap_names
-    names = []
-    Pathname.glob("#{HOMEBREW_LIBRARY}/Taps/*/*/") do |tap|
-      tap.find_formula do |formula|
-        formula.to_s =~ HOMEBREW_TAP_PATH_REGEX
-        names << "#{$1}/#{$2.gsub(/^homebrew-/, "")}/#{formula.basename(".rb")}"
-      end
-    end
-    names.sort
+    Tap.map(&:formula_names).flatten.sort
   end
 
   # an array of all {Formula} names

Library/Homebrew/formulary.rb

@@ -136,16 +136,9 @@ class Formulary
     def initialize tapped_name
       @tapped_name = tapped_name
       user, repo, name = tapped_name.split("/", 3).map(&:downcase)
-      tap = Pathname.new("#{HOMEBREW_LIBRARY}/Taps/#{user}/homebrew-#{repo}")
-      path = tap.join("#{name}.rb")
-
-      if tap.directory?
-        tap.find_formula do |file|
-          if file.basename(".rb").to_s == name
-            path = file
-          end
-        end
-      end
+      tap = Tap.new user, repo
+      path = tap.formula_files.detect { |file| file.basename(".rb").to_s == name }
+      path ||= tap.path/"#{name}.rb"
 
       super name, path
     end