From 7c9e8927e94e8637eb7c75ce87ca78ffe204f73c Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Fri, 3 May 2024 16:08:22 +0100
Subject: [PATCH] tap: memoize allowed and forbidden taps

---
 Library/Homebrew/tap.rb | 39 +++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 14 deletions(-)

diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index cf3da6e358..527fc0e156 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -132,29 +132,40 @@ class Tap
     false
   end
 
+  # rubocop:disable Style/ClassVars
+  # We want the the class variables below to be global to all `Tap` classes and subclasses.
   sig { returns(T::Set[Tap]) }
   def self.allowed_taps
-    allowed_tap_list = Homebrew::EnvConfig.allowed_taps.to_s.split
+    @@allowed_taps ||= begin
+      allowed_tap_list = Homebrew::EnvConfig.allowed_taps.to_s.split
 
-    Set.new(allowed_tap_list.filter_map do |tap|
-      Tap.fetch(tap)
-    rescue Tap::InvalidNameError
-      opoo "Invalid tap name in `HOMEBREW_ALLOWED_TAPS`: #{tap}"
-      nil
-    end)
+      Set.new(allowed_tap_list.filter_map do |tap|
+        Tap.fetch(tap)
+      rescue Tap::InvalidNameError
+        opoo "Invalid tap name in `HOMEBREW_ALLOWED_TAPS`: #{tap}"
+        nil
+      end)
+    end
+
+    @@allowed_taps.freeze
   end
 
   sig { returns(T::Set[Tap]) }
   def self.forbidden_taps
-    forbidden_tap_list = Homebrew::EnvConfig.forbidden_taps.to_s.split
+    @@forbidden_taps ||= begin
+      forbidden_tap_list = Homebrew::EnvConfig.forbidden_taps.to_s.split
 
-    Set.new(forbidden_tap_list.filter_map do |tap|
-      Tap.fetch(tap)
-    rescue Tap::InvalidNameError
-      opoo "Invalid tap name in `HOMEBREW_FORBIDDEN_TAPS`: #{tap}"
-      nil
-    end)
+      Set.new(forbidden_tap_list.filter_map do |tap|
+        Tap.fetch(tap)
+      rescue Tap::InvalidNameError
+        opoo "Invalid tap name in `HOMEBREW_FORBIDDEN_TAPS`: #{tap}"
+        nil
+      end)
+    end
+
+    @@forbidden_taps.freeze
   end
+  # rubocop:enable Style/ClassVars
 
   # @api public
   extend Enumerable