Add Ruby implementation using parallel gem

bin/nit-ruby

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+exec ruby "${SCRIPT_DIR}/../ruby/nit.rb" "$@"

ruby/Gemfile

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+source "https://rubygems.org"
+
+gem "parallel", "~> 1.24"
+
+group :development, :test do
+  gem "rspec", "~> 3.12"
+end

ruby/Gemfile.lock

@@ -0,0 +1,38 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    diff-lcs (1.6.2)
+    parallel (1.27.0)
+    rspec (3.13.2)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.6)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.5)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.7)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.6)
+
+PLATFORMS
+  arm64-darwin-24
+  ruby
+
+DEPENDENCIES
+  parallel (~> 1.24)
+  rspec (~> 3.12)
+
+CHECKSUMS
+  diff-lcs (1.6.2) sha256=9ae0d2cba7d4df3075fe8cd8602a8604993efc0dfa934cff568969efb1909962
+  parallel (1.27.0) sha256=4ac151e1806b755fb4e2dc2332cbf0e54f2e24ba821ff2d3dcf86bf6dc4ae130
+  rspec (3.13.2) sha256=206284a08ad798e61f86d7ca3e376718d52c0bc944626b2349266f239f820587
+  rspec-core (3.13.6) sha256=a8823c6411667b60a8bca135364351dda34cd55e44ff94c4be4633b37d828b2d
+  rspec-expectations (3.13.5) sha256=33a4d3a1d95060aea4c94e9f237030a8f9eae5615e9bd85718fe3a09e4b58836
+  rspec-mocks (3.13.7) sha256=0979034e64b1d7a838aaaddf12bf065ea4dc40ef3d4c39f01f93ae2c66c62b1c
+  rspec-support (3.13.6) sha256=2e8de3702427eab064c9352fe74488cc12a1bfae887ad8b91cba480ec9f8afb2
+
+BUNDLED WITH
+   2.7.2

ruby/nit.rb

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+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "optparse"
+require "open3"
+require "parallel"
+require "shellwords"
+
+VERSION = "0.1.0"
+MAX_REPO_NAME_WIDTH = 24
+
+# === Passthrough Check ===
+# Per SPEC.md 1.1: Must check if inside git repo before any other operation
+
+def inside_git_repo?
+  system("git", "rev-parse", "--git-dir", out: File::NULL, err: File::NULL)
+end
+
+# === GitCommand Struct ===
+# Critical: to_s (dry-run) and run both use to_cmd - same code path per SPEC.md 6.1.1
+
+GitCommand = Struct.new(:repo, :args, :url_scheme) do
+  def to_cmd
+    cmd = ["git"]
+    case url_scheme
+    when :ssh
+      cmd += ["-c", "url.git@github.com:.insteadOf=https://github.com/"]
+    when :https
+      cmd += ["-c", "url.https://github.com/.insteadOf=git@github.com:"]
+    end
+    cmd += ["-C", repo] + args
+  end
+
+  def to_s
+    to_cmd.shelljoin
+  end
+
+  def run
+    Open3.capture3({ "GIT_TERMINAL_PROMPT" => "0" }, *to_cmd)
+  end
+end
+
+# === Output Formatters ===
+
+FORMATTERS = {
+  status: lambda { |stdout, stderr, success|
+    return "ERROR: #{stderr.lines.first&.strip || 'failed'}" unless success
+
+    modified = 0
+    untracked = 0
+
+    stdout.each_line do |line|
+      next if line.length < 2
+
+      if line.start_with?("??")
+        untracked += 1
+      elsif line =~ /^[ MADRCU][MD]|^[MADRCU][ MD]/
+        modified += 1
+      end
+    end
+
+    return "clean" if modified.zero? && untracked.zero?
+
+    parts = []
+    parts << "#{modified} modified" if modified > 0
+    parts << "#{untracked} untracked" if untracked > 0
+    parts.join(", ")
+  },
+
+  pull: lambda { |stdout, stderr, success|
+    return "ERROR: #{stderr.lines.first&.strip || 'failed'}" unless success
+    return "Already up to date" if stdout.include?("Already up to date")
+
+    # Match both "1 file changed" and "N files changed"
+    stdout.lines.find { |l| l.include?("file changed") || l.include?("files changed") }&.strip || "completed"
+  },
+
+  fetch: lambda { |stdout, stderr, success|
+    return "ERROR: #{stderr.lines.first&.strip || 'failed'}" unless success
+    return "no new commits" if stdout.strip.empty? && stderr.strip.empty?
+
+    "fetched"
+  },
+
+  passthrough: lambda { |stdout, stderr, success|
+    return "ERROR: #{stderr.lines.first&.strip || 'failed'}" unless success
+
+    stdout.lines.first&.strip || stderr.lines.first&.strip || "ok"
+  }
+}.freeze
+
+# === Helper Functions ===
+
+def find_repos
+  Dir.glob("*/.git").map { |p| File.dirname(p) }.sort
+end
+
+def format_repo_name(name)
+  display = if name.length > MAX_REPO_NAME_WIDTH
+    "#{name[0, MAX_REPO_NAME_WIDTH - 4]}-..."
+  else
+    name
+  end
+  "[#{display.ljust(MAX_REPO_NAME_WIDTH)}]"
+end
+
+# === Parallel Execution ===
+
+def run_parallel(repos, command:, args:, dry_run:, workers:, url_scheme:, formatter:)
+  # Build commands for all repos
+  commands = repos.map do |repo|
+    full_args = case command
+    when "status"
+      ["status", "--porcelain"] + args
+    else
+      [command] + args
+    end
+    GitCommand.new(repo, full_args, url_scheme)
+  end
+
+  # Dry-run: print commands and exit
+  if dry_run
+    puts "[nit v#{VERSION}] Running in **dry-run mode**, no git commands will be executed. Planned git commands below."
+    commands.each { |cmd| puts cmd.to_s }
+    return
+  end
+
+  # Parallel execution with processes
+  worker_count = workers.zero? ? repos.size : [workers, repos.size].min
+
+  results = Parallel.map(commands, in_processes: worker_count) do |cmd|
+    stdout, stderr, status = cmd.run
+    { repo: cmd.repo, stdout: stdout, stderr: stderr, success: status.success? }
+  end
+
+  # Print results in order (Parallel.map preserves order)
+  results.each do |r|
+    name = format_repo_name(File.basename(r[:repo]))
+    output = formatter.call(r[:stdout], r[:stderr], r[:success])
+    puts "#{name} #{output}"
+  end
+end
+
+# === Main Entry Point ===
+# Only execute when run directly (not when required for testing)
+
+if __FILE__ == $0
+  # Passthrough check FIRST per SPEC.md 1.1
+  if inside_git_repo?
+    exec("git", *ARGV) # Never returns - replaces process with git
+  end
+
+  # CLI Parsing
+  options = { dry_run: false, workers: 8, url_scheme: nil }
+
+  parser = OptionParser.new do |opts|
+    opts.banner = "Usage: nit [OPTIONS] <COMMAND> [ARGS...]"
+    opts.separator ""
+    opts.separator "Commands:"
+    opts.separator "  status    Show status of all repositories"
+    opts.separator "  pull      Pull all repositories"
+    opts.separator "  fetch     Fetch all repositories"
+    opts.separator "  <other>   Pass through to git"
+    opts.separator ""
+    opts.separator "Options:"
+
+    opts.on("--dry-run", "Print exact commands without executing") do
+      options[:dry_run] = true
+    end
+
+    opts.on("-n", "--max-connections NUM", Integer, "Max concurrent git processes (default: 8, 0 = unlimited)") do |n|
+      options[:workers] = n
+    end
+
+    opts.on("--ssh", "Force SSH URLs for all remotes") do
+      options[:url_scheme] = :ssh
+    end
+
+    opts.on("--https", "Force HTTPS URLs for all remotes") do
+      options[:url_scheme] = :https
+    end
+
+    opts.on("-V", "--version", "Print version") do
+      puts "nit #{VERSION}"
+      exit
+    end
+
+    opts.on("-h", "--help", "Print help") do
+      puts opts
+      exit
+    end
+  end
+
+  begin
+    args = parser.order(ARGV) # Parse options, stop at first non-option
+  rescue OptionParser::InvalidOption => e
+    warn "nit: #{e.message}"
+    exit 1
+  end
+
+  command = args.shift
+  git_args = args
+
+  # Main Execution
+  repos = find_repos
+
+  if repos.empty?
+    puts "No git repositories found in current directory"
+    exit 0
+  end
+
+  # Handle no command - default to showing help
+  if command.nil?
+    warn "nit: no command specified"
+    warn parser
+    exit 1
+  end
+
+  formatter = case command
+  when "status" then FORMATTERS[:status]
+  when "pull" then FORMATTERS[:pull]
+  when "fetch" then FORMATTERS[:fetch]
+  else FORMATTERS[:passthrough]
+  end
+
+  run_parallel(
+    repos,
+    command: command,
+    args: git_args,
+    dry_run: options[:dry_run],
+    workers: options[:workers],
+    url_scheme: options[:url_scheme],
+    formatter: formatter
+  )
+end