Add a new RuboCop for alphabetizing zap trash array elements

- Part of issue 16323.
- Previously this was being done manually by Cask maintainers.
- While we're here, enforce that the `zap trash` path is not in `[]` if
  it only contains a single element.
- This is buggy on actual Casks, hence the draft PR.

Library/Homebrew/rubocops/cask/array_alphabetization.rb

@@ -0,0 +1,38 @@
+# typed: true
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Cask
+      class ArrayAlphabetization < Base
+        extend AutoCorrector
+
+        def on_send(node)
+          return if node.method_name != :zap
+
+          node.each_descendant(:pair).each do |pair|
+            pair.each_descendant(:array).each do |array|
+              if array.children.length == 1
+                add_offense(array, message: "Remove the `[]` around a single `zap trash` path") do |corrector|
+                  corrector.replace(array.source_range, array.children.first.source)
+                end
+              end
+
+              array.each_descendant(:str).each_cons(2) do |first, second|
+                next if first.source < second.source
+
+                add_offense(second, message: "The `zap trash` paths should be in alphabetical order") do |corrector|
+                  corrector.insert_before(first.source_range, second.source)
+                  corrector.insert_before(second.source_range, first.source)
+                  # Using `corrector.replace` here trips the clobbering detection.
+                  corrector.remove(first.source_range)
+                  corrector.remove(second.source_range)
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

Library/Homebrew/rubocops/rubocop-cask.rb

@@ -12,6 +12,7 @@ require_relative "cask/extend/node"
 require_relative "cask/mixin/cask_help"
 require_relative "cask/mixin/on_homepage_stanza"
 require_relative "cask/mixin/on_url_stanza"
+require_relative "cask/array_alphabetization"
 require_relative "cask/desc"
 require_relative "cask/homepage_url_trailing_slash"
 require_relative "cask/no_overrides"

Library/Homebrew/test/rubocops/cask/array_alphabetization_spec.rb

@@ -0,0 +1,59 @@
+
+# frozen_string_literal: true
+
+require "rubocops/rubocop-cask"
+
+describe RuboCop::Cop::Cask::ArrayAlphabetization, :config do
+  it "reports an offense when a single `zap trash` path is specified in an array" do
+    source = <<~CASK
+      cask "foo" do
+        url "https://example.com/foo.zip"
+
+        zap trash: ["~/Library/Application Support/Foo"]
+                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Remove the `[]` around a single `zap trash` path
+      end
+    CASK
+
+    expect_offense(source)
+    expect_correction(<<~CASK)
+      cask "foo" do
+        url "https://example.com/foo.zip"
+
+        zap trash: "~/Library/Application Support/Foo"
+      end
+    CASK
+  end
+
+  it "reports an offense when the `zap trash` paths are not in alphabetical order" do
+    source = <<~CASK
+      cask "foo" do
+        url "https://example.com/foo.zip"
+
+        zap trash: [
+          "/Library/Application Support/Foo",
+          "/Library/Application Support/Baz",
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The `zap trash` paths should be in alphabetical order
+          "~/Library/Application Support/Foo",
+          "~/.dotfiles/thing",
+          ^^^^^^^^^^^^^^^^^^^ The `zap trash` paths should be in alphabetical order
+          "~/Library/Application Support/Bar",
+        ]
+      end
+    CASK
+
+    expect_offense(source)
+    expect_correction(<<~CASK)
+      cask "foo" do
+        url "https://example.com/foo.zip"
+
+        zap trash: [
+          "/Library/Application Support/Baz",
+          "/Library/Application Support/Foo",
+          "~/.dotfiles/thing",
+          "~/Library/Application Support/Bar",
+          "~/Library/Application Support/Foo",
+        ]
+      end
+    CASK
+  end
+end