Add which entry command

Library/Homebrew/dev-cmd/which-entry.rb

@@ -0,0 +1,69 @@
+# typed: strict
+# frozen_string_literal: true
+
+require "abstract_command"
+require "formula"
+require "formulary"
+
+module Homebrew
+  module DevCmd
+    class WhichEntry < AbstractCommand
+      cmd_args do
+        description <<~EOS
+          Generate an `executables.txt` entry for <formula> using bottle manifest metadata.
+        EOS
+        flag "--output-db=",
+             description: "Append or update the entry in the given `executables.txt` database file."
+        named_args :formula, min: 1
+      end
+
+      sig { override.void }
+      def run
+        db_path = args.output_db
+        raise UsageError, "`--output-db` is required." unless db_path
+
+        args.named.to_formulae.each { |formula| process(formula, db_path: Pathname(db_path)) }
+      end
+
+      private
+
+      sig { params(formula: Formula, db_path: Pathname).void }
+      def process(formula, db_path:)
+        line = db_line(formula)
+        write_db(db_path, formula.full_name, line)
+      end
+
+      sig { params(db_path: Pathname, name: String, line: T.nilable(String)).void }
+      def write_db(db_path, name, line)
+        lines = db_path.readlines(chomp: true).compact_blank if db_path.exist?
+        # TODO: remove once pkg_versions are no longer in executables.txt
+        lines = Array(lines).reject { |l| l.start_with?(/#{Regexp.escape(name)}(?:\(.+\))?:/) }
+        lines << line if line
+        db_path.write("#{lines.sort.join("\n")}\n")
+      end
+
+      sig { params(formula: Formula).returns(T.nilable(String)) }
+      def db_line(formula)
+        return if formula.disabled? || formula.deprecated?
+
+        exes = executables_from_manifest(formula)
+        "#{formula.full_name}:#{exes.join(" ")}"
+      end
+
+      sig { params(formula: Formula).returns(T::Array[String]) }
+      def executables_from_manifest(formula)
+        manifest_resource = formula.bottle&.github_packages_manifest_resource
+        return [] unless manifest_resource
+
+        manifest_resource.fetch unless manifest_resource.downloaded?
+        manifest_path = manifest_resource.cached_download
+        return [] unless manifest_path.exist?
+
+        manifest_resource.path_exec_files
+      rescue JSON::ParserError => e
+        opoo "Failed to parse bottle manifest for #{formula.name}: #{e.message}"
+        []
+      end
+    end
+  end
+end

Library/Homebrew/resource.rb

@@ -411,6 +411,14 @@ def installed_size
       manifest_annotations["sh.brew.bottle.installed_size"]&.to_i
     end
 
+    sig { returns(T::Array[String]) }
+    def path_exec_files
+      exec_files = manifest_annotations["sh.brew.path_exec_files"]
+      return [] if exec_files.blank?
+
+      exec_files.split.map { |f| File.basename(f) }.sort
+    end
+
     sig { override.returns(String) }
     def download_queue_type = "Bottle Manifest"
 

Library/Homebrew/test/dev-cmd/which-entry_spec.rb

@@ -0,0 +1,15 @@
+# typed: false
+# frozen_string_literal: true
+
+require "cmd/shared_examples/args_parse"
+require "dev-cmd/which-entry"
+
+RSpec.describe Homebrew::DevCmd::WhichEntry do
+  it_behaves_like "parseable arguments"
+
+  it "raises a UsageError if --output-db is not passed", :integration_test do
+    expect { brew "which-entry", "wget" }
+      .to output(/`--output-db` is required/).to_stderr
+      .and be_a_failure
+  end
+end