Merge pull request #13496 from mohammadzainabbas/mohammad

Extend the `livecheck` DSL to work for resources

Library/Homebrew/livecheck.rb

@@ -1,9 +1,10 @@
 # typed: true
 # frozen_string_literal: true
 
-# The {Livecheck} class implements the DSL methods used in a formula's or cask's
+# The {Livecheck} class implements the DSL methods used in a formula's, cask's
-# `livecheck` block and stores related instance variables. Most of these methods
+# or resource's `livecheck` block and stores related instance variables. Most
-# also return the related instance variable when no argument is provided.
+# of these methods also return the related instance variable when no argument
+# is provided.
 #
 # This information is used by the `brew livecheck` command to control its
 # behavior. Example `livecheck` blocks can be found in the
@@ -11,13 +12,13 @@
 class Livecheck
   extend Forwardable
 
-  # A very brief description of why the formula/cask is skipped (e.g. `No longer
+  # A very brief description of why the formula/cask/resource is skipped (e.g.
-  # developed or maintained`).
+  # `No longer developed or maintained`).
   # @return [String, nil]
   attr_reader :skip_msg
 
-  def initialize(formula_or_cask)
+  def initialize(package_or_resource)
-    @formula_or_cask = formula_or_cask
+    @package_or_resource = package_or_resource
     @referenced_cask_name = nil
     @referenced_formula_name = nil
     @regex = nil
@@ -81,8 +82,9 @@ class Livecheck
 
   # Sets the `@skip` instance variable to `true` and sets the `@skip_msg`
   # instance variable if a `String` is provided. `@skip` is used to indicate
-  # that the formula/cask should be skipped and the `skip_msg` very briefly
+  # that the formula/cask/resource should be skipped and the `skip_msg` very
-  # describes why it is skipped (e.g. "No longer developed or maintained").
+  # briefly describes why it is skipped (e.g. "No longer developed or
+  # maintained").
   #
   # @param skip_msg [String] string describing why the formula/cask is skipped
   # @return [Boolean]
@@ -96,7 +98,7 @@ class Livecheck
     @skip = true
   end
 
-  # Should `livecheck` skip this formula/cask?
+  # Should `livecheck` skip this formula/cask/resource?
   def skip?
     @skip
   end
@@ -126,7 +128,7 @@ class Livecheck
   # Sets the `@url` instance variable to the provided argument or returns the
   # `@url` instance variable when no argument is provided. The argument can be
   # a `String` (a URL) or a supported `Symbol` corresponding to a URL in the
-  # formula/cask (e.g. `:stable`, `:homepage`, `:head`, `:url`).
+  # formula/cask/resource (e.g. `:stable`, `:homepage`, `:head`, `:url`).
   # @param val [String, Symbol] URL to check for version information
   # @return [String, nil]
   def url(val = nil)
@@ -140,7 +142,7 @@ class Livecheck
     end
   end
 
-  delegate version: :@formula_or_cask
+  delegate version: :@package_or_resource
   private :version
 
   # Returns a `Hash` of all instance variable values.

Library/Homebrew/resource.rb

@@ -5,6 +5,7 @@ require "download_strategy"
 require "checksum"
 require "version"
 require "mktemp"
+require "livecheck"
 require "extend/on_system"
 
 # Resource is the fundamental representation of an external resource. The
@@ -36,6 +37,8 @@ class Resource
     @checksum = nil
     @using = nil
     @patches = []
+    @livecheck = nil
+    @livecheckable = false
     instance_eval(&block) if block
   end
 
@@ -168,6 +171,32 @@ class Resource
     EOS
   end
 
+  # @!attribute [w] livecheck
+  # {Livecheck} can be used to check for newer versions of the software.
+  # This method evaluates the DSL specified in the livecheck block of the
+  # {Resource} (if it exists) and sets the instance variables of a {Livecheck}
+  # object accordingly. This is used by `brew livecheck` to check for newer
+  # versions of the software.
+  #
+  # <pre>livecheck do
+  #   url "https://example.com/foo/releases"
+  #   regex /foo-(\d+(?:\.\d+)+)\.tar/
+  # end</pre>
+  def livecheck(&block)
+    @livecheck ||= Livecheck.new(self) if block
+    return @livecheck unless block
+
+    @livecheckable = true
+    @livecheck.instance_eval(&block)
+  end
+
+  # Whether a livecheck specification is defined or not.
+  # It returns true when a livecheck block is present in the {Resource} and
+  # false otherwise, and is used by livecheck.
+  def livecheckable?
+    @livecheckable == true
+  end
+
   def sha256(val)
     @checksum = Checksum.new(val)
   end

Library/Homebrew/test/resource_spec.rb

@@ -2,10 +2,23 @@
 # frozen_string_literal: true
 
 require "resource"
+require "livecheck"
 
 describe Resource do
   subject(:resource) { described_class.new("test") }
 
+  let(:livecheck_resource) {
+    described_class.new do
+      url "https://brew.sh/foo-1.0.tar.gz"
+      sha256 "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
+
+      livecheck do
+        url "https://brew.sh/test/releases"
+        regex(/foo[._-]v?(\d+(?:\.\d+)+)\.t/i)
+      end
+    end
+  }
+
   describe "#url" do
     it "sets the URL" do
       resource.url("foo")
@@ -52,6 +65,27 @@ describe Resource do
     end
   end
 
+  describe "#livecheck" do
+    it "returns nil if livecheck block is not set in resource" do
+      expect(resource.livecheck).to be_nil
+    end
+
+    specify "when livecheck block is set" do
+      expect(livecheck_resource.livecheck.url).to eq("https://brew.sh/test/releases")
+      expect(livecheck_resource.livecheck.regex).to eq(/foo[._-]v?(\d+(?:\.\d+)+)\.t/i)
+    end
+  end
+
+  describe "#livecheckable?" do
+    it "returns false if livecheck block is not set in resource" do
+      expect(resource.livecheckable?).to be false
+    end
+
+    specify "livecheck block defined in resources" do
+      expect(livecheck_resource.livecheckable?).to be true
+    end
+  end
+
   describe "#version" do
     it "sets the version" do
       resource.version("1.0")