cask audit: installer and pkg require uninstall

Library/Homebrew/cask/lib/hbc/audit.rb

@@ -36,6 +36,7 @@ module Hbc
       check_untrusted_pkg
       check_github_releases_appcast
       check_latest_with_appcast
+      check_stanza_requires_uninstall
       self
     rescue StandardError => e
       odebug "#{e.message}\n#{e.backtrace.join("\n")}"
@@ -65,6 +66,14 @@ module Hbc
       add_warning "allow_untrusted is not permitted in official Homebrew-Cask taps"
     end
 
+    def check_stanza_requires_uninstall
+      odebug "Auditing stanzas which require an uninstall"
+
+      return if cask.artifacts.none? { |k| k.is_a?(Hbc::Artifact::Pkg) || k.is_a?(Hbc::Artifact::Installer) }
+      return if cask.artifacts.any? { |k| k.is_a?(Hbc::Artifact::Uninstall) }
+      add_warning "installer and pkg stanzas require an uninstall stanza"
+    end
+
     def check_single_pre_postflight
       odebug "Auditing preflight and postflight stanzas"
 

Library/Homebrew/test/cask/audit_spec.rb

@@ -115,6 +115,40 @@ describe Hbc::Audit, :cask do
       end
     end
 
+    describe "when the Cask stanza requires uninstall" do
+      let(:error_msg) { "installer and pkg stanzas require an uninstall stanza" }
+
+      context "when the Cask does not require an uninstall" do
+        let(:cask_token) { "basic-cask" }
+
+        it { is_expected.not_to warn_with(error_msg) }
+      end
+
+      context "when the pkg Cask has an uninstall" do
+        let(:cask_token) { "with-uninstall-pkgutil" }
+
+        it { is_expected.not_to warn_with(error_msg) }
+      end
+
+      context "when the installer Cask has an uninstall" do
+        let(:cask_token) { "installer-with-uninstall" }
+
+        it { is_expected.not_to warn_with(error_msg) }
+      end
+
+      context "when the installer Cask does not have an uninstall" do
+        let(:cask_token) { "with-installer-manual" }
+
+        it { is_expected.to warn_with(error_msg) }
+      end
+
+      context "when the pkg Cask does not have an uninstall" do
+        let(:cask_token) { "pkg-without-uninstall" }
+
+        it { is_expected.to warn_with(error_msg) }
+      end
+    end
+
     describe "preflight stanza checks" do
       let(:error_msg) { "only a single preflight stanza is allowed" }
 

Library/Homebrew/test/support/fixtures/cask/Casks/installer-with-uninstall.rb

@@ -0,0 +1,11 @@
+cask 'installer-with-uninstall' do
+  version '1.2.3'
+  sha256 '67cdb8a02803ef37fdbf7e0be205863172e41a561ca446cd84f0d7ab35a99d94'
+
+  url "file://#{TEST_FIXTURE_DIR}/cask/caffeine.zip"
+  homepage 'http://example.com/local-caffeine'
+
+  installer manual: 'Caffeine.app'
+
+  uninstall delete: '/Applications/Caffeine.app'
+end

Library/Homebrew/test/support/fixtures/cask/Casks/pkg-without-uninstall.rb

@@ -0,0 +1,9 @@
+cask 'pkg-without-uninstall' do
+  version '1.2.3'
+  sha256 '8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b'
+
+  url "file://#{TEST_FIXTURE_DIR}/cask/MyFancyPkg.zip"
+  homepage 'http://example.com/fancy-pkg'
+
+  pkg 'Fancy.pkg'
+end