brew/Library/Homebrew/dev-cmd/prof.rb

# typed: true
# frozen_string_literal: true

require "cli/parser"

module Homebrew
  module_function

  sig { returns(CLI::Parser) }
  def prof_args
    Homebrew::CLI::Parser.new do
      description <<~EOS
        Run Homebrew with a Ruby profiler. For example, `brew prof readall`.
      EOS
      switch "--stackprof",
             description: "Use `stackprof` instead of `ruby-prof` (the default)."

      named_args :command, min: 1
    end
  end

  def prof
    args = prof_args.parse

    Homebrew.install_bundler_gems!(groups: ["prof"])

    brew_rb = (HOMEBREW_LIBRARY_PATH/"brew.rb").resolved_path
    FileUtils.mkdir_p "prof"
    cmd = args.named.first

    case Commands.path(cmd)&.extname
    when ".rb"
      # expected file extension so we do nothing
    when ".sh"
      raise UsageError, <<~EOS
        `#{cmd}` is a Bash command!
        Try `hyperfine` for benchmarking instead.
      EOS
    else
      raise UsageError, "`#{cmd}` is an unknown command!"
    end

    if args.stackprof?
      with_env HOMEBREW_STACKPROF: "1" do
        system(*HOMEBREW_RUBY_EXEC_ARGS, brew_rb, *args.named)
      end
      output_filename = "prof/d3-flamegraph.html"
      safe_system "stackprof --d3-flamegraph prof/stackprof.dump > #{output_filename}"
    else
      output_filename = "prof/call_stack.html"
      safe_system "ruby-prof", "--printer=call_stack", "--file=#{output_filename}", brew_rb, "--", *args.named
    end

    exec_browser output_filename
  rescue OptionParser::InvalidOption => e
    ofail e

    # The invalid option could have been meant for the subcommand.
    # Suggest `brew prof list -r` -> `brew prof -- list -r`
    args = ARGV - ["--"]
    puts "Try `brew prof -- #{args.join(" ")}` instead."
  end
end