Safe access to tap attributes

Prevent calling name tap attribute when the tap is nil

Co-Authored-By: Rylan Polster <rslpolster@gmail.com>

Library/Homebrew/cask/cask.rb

@@ -169,8 +169,8 @@ module Cask
     def to_h
       {
         "token"          => token,
-        "full_token"     => "#{tap.name}/#{token}",
-        "tap"            => tap.name,
+        "full_token"     => full_name,
+        "tap"            => tap&.name,
         "name"           => name,
         "desc"           => desc,
         "homepage"       => homepage,

Library/Homebrew/formula.rb

@@ -1766,7 +1766,7 @@ class Formula
     hsh = {
       "name"                     => name,
       "full_name"                => full_name,
-      "tap"                      => tap.name,
+      "tap"                      => tap&.name,
       "oldname"                  => oldname,
       "aliases"                  => aliases.sort,
       "versioned_formulae"       => versioned_formulae.map(&:name),