Don't tap user-untapped official taps

Library/Homebrew/brew.rb

@@ -132,7 +132,10 @@ begin
     possible_tap = OFFICIAL_CMD_TAPS.find { |_, cmds| cmds.include?(cmd) }
     possible_tap = Tap.fetch(possible_tap.first) if possible_tap
 
-    odie "Unknown command: #{cmd}" if !possible_tap || possible_tap.installed?
+    untapped_official_taps = Homebrew::Settings.read(:untapped)&.split(";") || []
+    if !possible_tap || possible_tap.installed? || untapped_official_taps.include?(possible_tap.name)
+      odie "Unknown command: #{cmd}"
+    end
 
     # Unset HOMEBREW_HELP to avoid confusing the tap
     with_env HOMEBREW_HELP: nil do

Library/Homebrew/extend/os/mac/tap.rb

@@ -5,6 +5,9 @@ class Tap
   def self.install_default_cask_tap_if_necessary
     return false if default_cask_tap.installed?
 
+    untapped_official_taps = Homebrew::Settings.read(:untapped)&.split(";") || []
+    return false if untapped_official_taps.include?(default_cask_tap.name)
+
     default_cask_tap.install
     true
   end

Library/Homebrew/tap.rb

@@ -326,6 +326,17 @@ class Tap
                            .update_from_formula_names!(formula_names)
     end
 
+    if official?
+      untapped = Homebrew::Settings.read(:untapped)&.split(";") || []
+      untapped -= [name]
+
+      if untapped.empty?
+        Homebrew::Settings.delete :untapped
+      else
+        Homebrew::Settings.write :untapped, untapped.join(";")
+      end
+    end
+
     return if clone_target
     return unless private?
     return if quiet
@@ -374,6 +385,15 @@ class Tap
 
     Commands.rebuild_commands_completion_list
     clear_cache
+
+    return unless official?
+
+    untapped = Homebrew::Settings.read(:untapped)&.split(";") || []
+
+    return if untapped.include? name
+
+    untapped << name
+    Homebrew::Settings.write :untapped, untapped.join(";")
   end
 
   # True if the {#remote} of {Tap} is customized.