Add gzipped executable action

Several binary formulae ship a gzipped executable that needs the same
guarded post-install expansion and mode handling.

- resolve serialised source and destination path bases
- skip absent payloads and replace stale expanded sources
- install each executable with an explicit literal permission mode

Author: MikeMcQuaid

Library/Homebrew/install_steps.rb

@@ -597,6 +597,20 @@ def configure_gcc_runtime
         add_step("configure_gcc_runtime")
       end
 
+      sig {
+        params(
+          source:      ::T.any(::String, ::Pathname),
+          target:      ::T.any(::String, ::Pathname),
+          source_base: ::T.nilable(::T.any(::String, ::Symbol)),
+          target_base: ::T.nilable(::T.any(::String, ::Symbol)),
+        ).void
+      }
+      def install_gzipped_executable(source, target, source_base: nil, target_base: nil)
+        add_step("install_gzipped_executable",
+                 "source" => path_spec(source, base: source_base, default_base: @default_source_base),
+                 "target" => path_spec(target, base: target_base, default_base: @default_target_base))
+      end
+
       private
 
       sig { params(guard: PathSpec, block: ::T.proc.void).void }
@@ -841,6 +855,8 @@ def run_install_step(step)
           opoo expand_template_tokens(step_string(step, "message"))
         when "configure_gcc_runtime"
           run_configure_gcc_runtime
+        when "install_gzipped_executable"
+          run_install_gzipped_executable(step)
         when "set_permissions"
           run_set_permissions(step)
         when "set_ownership"

Library/Homebrew/install_steps/formula_actions.rb

@@ -61,6 +61,29 @@ def run_configure_gcc_runtime
         EOS
         specs.write(specs.read.gsub(" %o ", "\\0%(homebrew_rpath) ")) if homebrew_rpath
       end
+
+      sig { params(step: Step).void }
+      def run_install_gzipped_executable(step)
+        source = resolve_path(step_path(step, "source"))
+        return unless source.exist?
+
+        require "unpack_strategy"
+
+        target = resolve_path(step_path(step, "target"))
+        target.dirname.mkpath
+        temporary_target = target.dirname/".#{target.basename}.install-step"
+        temporary_gzip = Pathname("#{temporary_target}.gz")
+        FileUtils.rm_f [temporary_target, temporary_gzip]
+        begin
+          UnpackStrategy::Gzip.new(source).extract(to: target.dirname, basename: temporary_gzip.basename)
+          FileUtils.rm_f target
+          FileUtils.mv temporary_target, target
+          source.unlink
+        ensure
+          FileUtils.rm_f [temporary_target, temporary_gzip]
+        end
+        target.chmod 0755
+      end
     end
   end
 end

Library/Homebrew/rubocops/shared/install_steps_helper.rb

@@ -17,7 +17,7 @@ module InstallStepsHelper
       PERMISSION_STEP_METHODS = [:set_permissions, :set_ownership].freeze
       COMMAND_STEP_METHODS = [:run, :terminate_process].freeze
       NOTICE_STEP_METHODS = [:warn_if_exists].freeze
-      FORMULA_ACTION_STEP_METHODS = [:configure_gcc_runtime].freeze
+      FORMULA_ACTION_STEP_METHODS = [:configure_gcc_runtime, :install_compressed_executable].freeze
       ALLOWED_STEP_METHODS = T.let(
         [*FILE_PREPARATION_STEP_METHODS, *LINK_STEP_METHODS, *CONFIG_WRITE_STEP_METHODS, *SERVICE_DATA_STEP_METHODS,
          *REBUILD_ACTION_STEP_METHODS, :set_permissions, *COMMAND_STEP_METHODS, *NOTICE_STEP_METHODS,

Library/Homebrew/test/install_steps_spec.rb

@@ -682,6 +682,34 @@
     runner.run(steps)
   end
 
+  specify "dispatches gzipped executable installation" do
+    steps = Homebrew::InstallSteps::DSL.build do
+      install_gzipped_executable "compressed.gz", "bin/executable"
+    end
+
+    runner = Homebrew::InstallSteps::Runner.new(context:)
+    expect(runner).to receive(:run_install_gzipped_executable)
+
+    runner.run(steps)
+  end
+
+  specify "installs a gzipped executable with a fixed mode" do
+    require "zlib"
+
+    source = root/"prefix/bin/executable.gz"
+    source.dirname.mkpath
+    Zlib::GzipWriter.open(source.to_s) { |gzip| gzip.write "executable" }
+    steps = Homebrew::InstallSteps::DSL.build(default_source_base: :prefix, default_target_base: :prefix) do
+      install_gzipped_executable "bin/executable.gz", "bin/executable"
+    end
+
+    Homebrew::InstallSteps::Runner.new(context:).run(steps)
+
+    target = root/"prefix/bin/executable"
+    expect(target).to be_executable.and have_attributes(read: "executable")
+    expect(source).not_to exist
+  end
+
   describe "runs gtk_update_icon_cache rebuild action" do
     let(:formula) { instance_double(Formula, opt_bin: root/"opt/bin") }
     let(:steps) do

Library/Homebrew/test/rubocops/install_steps_spec.rb

@@ -42,7 +42,7 @@ class Foo < Formula
 
         post_install_steps do
           system "true"
-          ^^^^^^^^^^^^^ FormulaAudit/InstallSteps: Steps blocks may only contain install step DSL calls: `mkdir`, `mkdir_p`, `touch`, `move`, `mv`, `move_children`, `copy`, `remove`, `inreplace`, `symlink`, `ln_s`, `ln_sf`, `link_dir`, `link_children`, `write`, `init_data_dir`, `compile_gsettings_schemas`, `gdk_pixbuf_query_loaders`, `gtk_update_icon_cache`, `update_mime_database`, `update_desktop_database`, `set_permissions`, `run`, `terminate_process`, `warn_if_exists`, `configure_gcc_runtime`.
+          ^^^^^^^^^^^^^ FormulaAudit/InstallSteps: Steps blocks may only contain install step DSL calls: `mkdir`, `mkdir_p`, `touch`, `move`, `mv`, `move_children`, `copy`, `remove`, `inreplace`, `symlink`, `ln_s`, `ln_sf`, `link_dir`, `link_children`, `write`, `init_data_dir`, `compile_gsettings_schemas`, `gdk_pixbuf_query_loaders`, `gtk_update_icon_cache`, `update_mime_database`, `update_desktop_database`, `set_permissions`, `run`, `terminate_process`, `warn_if_exists`, `configure_gcc_runtime`, `install_compressed_executable`.
         end
       end
     RUBY
@@ -66,6 +66,7 @@ class Foo < Formula
           terminate_process "foo", retries: 2
           warn_if_exists "foo", "foo exists"
           configure_gcc_runtime
+          install_compressed_executable "compressed", "bin/executable"
           write "foo/banner", <<~TEXT
             literal banner
           TEXT
@@ -89,7 +90,7 @@ class Foo < Formula
 
         post_install_steps do
           write "foo.conf", "prefix = #{prefix}"
-                                      ^^^^^^^^^ FormulaAudit/InstallSteps: Steps blocks may only contain install step DSL calls: `mkdir`, `mkdir_p`, `touch`, `move`, `mv`, `move_children`, `copy`, `remove`, `inreplace`, `symlink`, `ln_s`, `ln_sf`, `link_dir`, `link_children`, `write`, `init_data_dir`, `compile_gsettings_schemas`, `gdk_pixbuf_query_loaders`, `gtk_update_icon_cache`, `update_mime_database`, `update_desktop_database`, `set_permissions`, `run`, `terminate_process`, `warn_if_exists`, `configure_gcc_runtime`.
+                                      ^^^^^^^^^ FormulaAudit/InstallSteps: Steps blocks may only contain install step DSL calls: `mkdir`, `mkdir_p`, `touch`, `move`, `mv`, `move_children`, `copy`, `remove`, `inreplace`, `symlink`, `ln_s`, `ln_sf`, `link_dir`, `link_children`, `write`, `init_data_dir`, `compile_gsettings_schemas`, `gdk_pixbuf_query_loaders`, `gtk_update_icon_cache`, `update_mime_database`, `update_desktop_database`, `set_permissions`, `run`, `terminate_process`, `warn_if_exists`, `configure_gcc_runtime`, `install_compressed_executable`.
         end
       end
     RUBY

docs/Formula-Cookbook.md

@@ -1238,6 +1238,7 @@ warn_if_exists "foo.conf", "Remove the old foo.conf before continuing", base: :e
 Use the named actions below for formula families that share post-install algorithms. Unique complex logic should be installed as a packaged helper and invoked with `run` instead of adding a formula-specific action.
 
 * `configure_gcc_runtime`: generate the Linux GCC runtime links and specs.
+* `install_compressed_executable`: unpack and install a gzipped executable.
 
 #### Service data directory steps