Add brew link --HEAD

Library/Homebrew/cli/named_args.rb

@@ -98,8 +98,9 @@ def load_formula_or_cask(name, only: nil, method: nil)
               Formulary.factory(name, *spec, force_bottle: @force_bottle, flags: @flags)
             when :resolve
               resolve_formula(name)
-            when :keg
-              resolve_keg(name)
+            # odeprecated "`method: :keg`"
+            when :keg, :default_kegs
+              resolve_default_keg(name)
             when :kegs
               _, kegs = resolve_kegs(name)
               kegs
@@ -208,10 +209,22 @@ def to_paths(only: parent&.only_formula_or_cask, recurse_tap: false)
         end.uniq.freeze
       end
 
+      sig { returns(T::Array[Keg]) }
+      def to_default_kegs
+        @to_default_kegs ||= begin
+          to_formulae_and_casks(only: :formula, method: :default_kegs).freeze
+        rescue NoSuchKegError => e
+          if (reason = MissingFormula.suggest_command(e.name, "uninstall"))
+            $stderr.puts reason
+          end
+          raise e
+        end
+      end
+
       sig { returns(T::Array[Keg]) }
       def to_kegs
         @to_kegs ||= begin
-          to_formulae_and_casks(only: :formula, method: :keg).freeze
+          to_formulae_and_casks(only: :formula, method: :kegs).freeze
         rescue NoSuchKegError => e
           if (reason = MissingFormula.suggest_command(e.name, "uninstall"))
             $stderr.puts reason
@@ -225,7 +238,7 @@ def to_kegs
           .returns([T::Array[Keg], T::Array[Cask::Cask]])
       }
       def to_kegs_to_casks(only: parent&.only_formula_or_cask, ignore_unavailable: nil, all_kegs: nil)
-        method = all_kegs ? :kegs : :keg
+        method = all_kegs ? :kegs : :default_kegs
         @to_kegs_to_casks ||= {}
         @to_kegs_to_casks[method] ||=
           to_formulae_and_casks(only: only, ignore_unavailable: ignore_unavailable, method: method)
@@ -282,7 +295,7 @@ def resolve_kegs(name)
         [rack, kegs]
       end
 
-      def resolve_keg(name)
+      def resolve_default_keg(name)
         rack, kegs = resolve_kegs(name)
 
         linked_keg_ref = HOMEBREW_LINKED_KEGS/rack.basename

Library/Homebrew/cmd/link.rb

@@ -26,6 +26,8 @@ def link_args
                           "`brew link --overwrite` without actually linking or deleting any files."
       switch "-f", "--force",
              description: "Allow keg-only formulae to be linked."
+      switch "--HEAD",
+             description: "Link the HEAD version of the formula if it is installed."
 
       named_args :installed_formula, min: 1
     end
@@ -40,16 +42,18 @@ def link
       verbose:   args.verbose?,
     }
 
-    args.named.to_kegs.each do |keg|
+    kegs = if args.HEAD?
+      args.named.to_kegs.filter { |keg| keg.version.head? }
+    else
+      args.named.to_default_kegs
+    end
+
+    kegs.freeze.each do |keg|
       keg_only = Formulary.keg_only?(keg.rack)
 
       if keg.linked?
         opoo "Already linked: #{keg}"
-        name_and_flag = if keg_only
-          "--force #{keg.name}"
-        else
-          keg.name
-        end
+        name_and_flag = "#{"--HEAD " if args.HEAD?}#{"--force " if keg_only}#{keg.name}"
         puts <<~EOS
           To relink:
             brew unlink #{keg.name} && brew link #{name_and_flag}

Library/Homebrew/cmd/list.rb

@@ -129,9 +129,10 @@ def list
         safe_system "ls", *ls_args, Cask::Caskroom.path
       end
     elsif args.verbose? || !$stdout.tty?
-      system_command! "find", args: args.named.to_kegs.map(&:to_s) + %w[-not -type d -print], print_stdout: true
+      system_command! "find", args:         args.named.to_default_kegs.map(&:to_s) + %w[-not -type d -print],
+                              print_stdout: true
     else
-      args.named.to_kegs.each { |keg| PrettyListing.new keg }
+      args.named.to_default_kegs.each { |keg| PrettyListing.new keg }
     end
   end
 

Library/Homebrew/cmd/unlink.rb

@@ -31,7 +31,7 @@ def unlink
 
     options = { dry_run: args.dry_run?, verbose: args.verbose? }
 
-    args.named.to_kegs.each do |keg|
+    args.named.to_default_kegs.each do |keg|
       if args.dry_run?
         puts "Would remove:"
         keg.unlink(**options)

Library/Homebrew/dev-cmd/linkage.rb

@@ -35,10 +35,10 @@ def linkage
     args = linkage_args.parse
 
     CacheStoreDatabase.use(:linkage) do |db|
-      kegs = if args.named.to_kegs.empty?
+      kegs = if args.named.to_default_kegs.empty?
         Formula.installed.map(&:any_installed_keg).reject(&:nil?)
       else
-        args.named.to_kegs
+        args.named.to_default_kegs
       end
       kegs.each do |keg|
         ohai "Checking #{keg.name} linkage" if kegs.size > 1

Library/Homebrew/test/cli/named_args_spec.rb

@@ -179,18 +179,38 @@ def setup_unredable_cask(name)
   describe "#to_kegs" do
     before do
       (HOMEBREW_CELLAR/"foo/1.0").mkpath
+      (HOMEBREW_CELLAR/"foo/2.0").mkpath
       (HOMEBREW_CELLAR/"bar/1.0").mkpath
     end
 
     it "resolves kegs with #resolve_kegs" do
-      expect(described_class.new("foo", "bar").to_kegs.map(&:name)).to eq ["foo", "bar"]
+      expect(described_class.new("foo", "bar").to_kegs.map(&:name)).to eq ["foo", "foo", "bar"]
+    end
+
+    it "resolves kegs with multiple versions with #resolve_keg" do
+      expect(described_class.new("foo").to_kegs.map(&->(k) { k.version.version })).to eq ["1.0", "2.0"]
     end
 
     it "when there are no matching kegs returns an array of Kegs" do
       expect(described_class.new.to_kegs).to be_empty
     end
   end
 
+  describe "#to_default_kegs" do
+    before do
+      (HOMEBREW_CELLAR/"foo/1.0").mkpath
+      (HOMEBREW_CELLAR/"bar/1.0").mkpath
+    end
+
+    it "resolves kegs with #resolve_default_keg" do
+      expect(described_class.new("foo", "bar").to_default_kegs.map(&:name)).to eq ["foo", "bar"]
+    end
+
+    it "when there are no matching kegs returns an array of Kegs" do
+      expect(described_class.new.to_default_kegs).to be_empty
+    end
+  end
+
   describe "#to_kegs_to_casks" do
     before do
       (HOMEBREW_CELLAR/"foo/1.0").mkpath