Cask::Audit: Handle livecheck skip conditions

Library/Homebrew/cask/audit.rb

@@ -552,8 +552,10 @@ module Cask
 
     def check_livecheck_version
       return unless appcast?
-      return :skip if cask.livecheck.skip?
-      return :latest if cask.version.latest?
+
+      # Respect cask skip conditions (e.g. discontinued, latest, unversioned)
+      skip_info = Homebrew::Livecheck::SkipConditions.skip_information(cask)
+      return :skip if skip_info.present?
 
       latest_version = Homebrew::Livecheck.latest_version(cask)&.fetch(:latest)
       if cask.version.to_s == latest_version.to_s

Library/Homebrew/test/cask/audit_spec.rb

@@ -411,6 +411,35 @@ describe Cask::Audit, :cask do
       end
     end
 
+    describe "livecheck should be skipped" do
+      let(:online) { true }
+      let(:message) { /Version '[^']*' differs from '[^']*' retrieved by livecheck\./ }
+
+      context "when the Cask has a livecheck block using skip" do
+        let(:cask_token) { "livecheck/livecheck-skip" }
+
+        it { is_expected.not_to fail_with(message) }
+      end
+
+      context "when the Cask is discontinued" do
+        let(:cask_token) { "livecheck/discontinued" }
+
+        it { is_expected.not_to fail_with(message) }
+      end
+
+      context "when version is :latest" do
+        let(:cask_token) { "livecheck/version-latest" }
+
+        it { is_expected.not_to fail_with(message) }
+      end
+
+      context "when url is unversioned" do
+        let(:cask_token) { "livecheck/url-unversioned" }
+
+        it { is_expected.not_to fail_with(message) }
+      end
+    end
+
     describe "when the Cask stanza requires uninstall" do
       let(:message) { "installer and pkg stanzas require an uninstall stanza" }
 

Library/Homebrew/test/support/fixtures/cask/Casks/livecheck/discontinued.rb

@@ -0,0 +1,18 @@
+cask "discontinued" do
+  version "1.2.3"
+  sha256 "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
+
+  # This cask is used in --online tests, so we use fake URLs to avoid impacting
+  # real servers. The URL paths are specific enough that they'll be
+  # understandable if they appear in local server logs.
+  url "http://localhost/homebrew/test/cask/audit/livecheck/discontinued-#{version}.dmg"
+  name "Discontinued"
+  desc "Cask for testing discontinued in livecheck"
+  homepage "http://localhost/homebrew/test/cask/audit/livecheck/discontinued"
+
+  app "TestCask.app"
+
+  caveats do
+    discontinued
+  end
+end

Library/Homebrew/test/support/fixtures/cask/Casks/livecheck/livecheck-skip.rb

@@ -0,0 +1,18 @@
+cask "livecheck-skip" do
+  version "1.2.3"
+  sha256 "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
+
+  # This cask is used in --online tests, so we use fake URLs to avoid impacting
+  # real servers. The URL paths are specific enough that they'll be
+  # understandable if they appear in local server logs.
+  url "http://localhost/homebrew/test/cask/audit/livecheck/livecheck-skip-#{version}.dmg"
+  name "Skip"
+  desc "Cask for testing skip in a livecheck block"
+  homepage "http://localhost/homebrew/test/cask/audit/livecheck/livecheck-skip"
+
+  livecheck do
+    skip "No version information available to check"
+  end
+
+  app "TestCask.app"
+end

Library/Homebrew/test/support/fixtures/cask/Casks/livecheck/url-unversioned.rb

@@ -0,0 +1,14 @@
+cask "url-unversioned" do
+  version "1.2.3"
+  sha256 "8c62a2b791cf5f0da6066a0a4b6e85f62949cd60975da062df44adf887f4370b"
+
+  # This cask is used in --online tests, so we use fake URLs to avoid impacting
+  # real servers. The URL paths are specific enough that they'll be
+  # understandable if they appear in local server logs.
+  url "http://localhost/homebrew/test/cask/audit/livecheck/url-unversioned.dmg"
+  name "Unversioned URL"
+  desc "Cask for testing an unversioned URL in livecheck"
+  homepage "http://localhost/homebrew/test/cask/audit/livecheck/url-unversioned"
+
+  app "TestCask.app"
+end

Library/Homebrew/test/support/fixtures/cask/Casks/livecheck/version-latest.rb

@@ -0,0 +1,14 @@
+cask "version-latest" do
+  version :latest
+  sha256 :no_check
+
+  # This cask is used in --online tests, so we use fake URLs to avoid impacting
+  # real servers. The URL paths are specific enough that they'll be
+  # understandable if they appear in local server logs.
+  url "http://localhost/homebrew/test/cask/audit/livecheck/version-latest.dmg"
+  name "Version Latest"
+  desc "Cask for testing a latest version in livecheck"
+  homepage "http://localhost/homebrew/test/cask/audit/livecheck/version-latest"
+
+  app "TestCask.app"
+end