Switch template-dir hooks from symlinks to regular files

Since symlinks are not supported on Windows, we need to swap these with
regular files so that the gem can be extracted on Windows machines.

We weren't hitting this problem before because it wasn't an issue in
earlier versions of Rubygems. There appears to have been some changes
around this in rubygems/rubygems@14b1eec7bd0f
and likely elsewhere, so perhaps the only reason it worked was because
of a bug.

To protect against the copies of the master hooks failing out of sync,
we added a hook to catch this. It's somewhat redundant since we have a
spec in spec/integration/template_dir_spec.rb, but this provides quicker
feedback, and we really want to make sure we don't screw up these hooks.

Fixes 387

Author: sds

.git-hooks/pre_commit/master_hooks_match.rb

@@ -0,0 +1,26 @@
+require 'fileutils'
+
+module Overcommit::Hook::PreCommit
+  # Ensures all master hooks have the same content.
+  #
+  # This is necessary because we can't use symlinks to link all the hooks in the
+  # template directory to the master `overcommit-hook` file, since symlinks are
+  # not supported on Windows.
+  class MasterHooksMatch < Base
+    def run
+      hooks_dir = File.join('template-dir', 'hooks')
+      master_hook = File.join(hooks_dir, 'overcommit-hook')
+      Dir.glob(File.join(hooks_dir, '*')).each do |hook_path|
+        unless FileUtils.compare_file(master_hook, hook_path)
+          return [
+            :fail,
+            "Template directory hook '#{hook_path}' does not match '#{master_hook}'!\n" \
+            "Run `cp #{master_hook} #{hook_path}`"
+          ]
+        end
+      end
+
+      :pass
+    end
+  end
+end

.overcommit.yml

@@ -14,6 +14,10 @@ PreCommit:
   HardTabs:
     enabled: true
 
+  MasterHooksMatch:
+    enabled: true
+    quiet: true
+
   RuboCop:
     enabled: true
     include:

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Overcommit Changelog
 
+## master (unreleased)
+
+* Switch template directory hooks from symlinks to regular files so gem can
+  be installed on Windows
+
 ## 0.34.0
 
 * Fix `Scalastyle` pre-commit hook to capture messages with no line number

spec/integration/template_dir_spec.rb

@@ -1,4 +1,5 @@
 require 'spec_helper'
+require 'fileutils'
 
 describe 'template directory' do
   let(:template_dir) { File.join(Overcommit::HOME, 'template-dir') }
@@ -16,15 +17,16 @@
       Overcommit::Utils::FileUtils.symlink?(master_hook).should == false
     end
 
-    it 'contains all other hooks as symlinks to the master hook' do
-      if Overcommit::OS.windows?
-        # Symlinks in template-dir are not compatible with Windows.
-        # Windows users will need to manually install Overcommit for now.
-        skip 'Unix symlinks not compatible with Windows'
+    it 'contains all other hooks as copies of the master hook' do
+      Overcommit::Utils.supported_hook_types.each do |hook_type|
+        FileUtils.compare_file(File.join(hooks_dir, hook_type),
+                               File.join(hooks_dir, 'overcommit-hook')).should == true
       end
+    end
 
+    it 'contains no symlinks' do
       Overcommit::Utils.supported_hook_types.each do |hook_type|
-        Overcommit::Utils::FileUtils.symlink?(File.join(hooks_dir, hook_type)).should == true
+        Overcommit::Utils::FileUtils.symlink?(File.join(hooks_dir, hook_type)).should == false
       end
     end
   end

template-dir/hooks/commit-msg

@@ -0,0 +1,115 @@
+#!/usr/bin/env ruby
+
+# Entrypoint for Overcommit hook integration. Installing Overcommit will result
+# in all of your git hooks being symlinked to this file, allowing the framework
+# to manage your hooks for you.
+
+# Prevent a Ruby stack trace from appearing when we interrupt the hook.
+# Note that this will be overridden when Overcommit is loaded, since the
+# InterruptHandler will redefine the trap at that time.
+Signal.trap('INT') do
+  puts 'Hook run interrupted'
+  exit 130
+end
+
+# Allow hooks to be disabled via environment variable so git commands can be run
+# in scripts without Overcommit running hooks
+if ENV['OVERCOMMIT_DISABLE'].to_i != 0 || ENV['OVERCOMMIT_DISABLED'].to_i != 0
+  exit
+end
+
+hook_type = File.basename($0)
+if hook_type == 'overcommit-hook'
+  puts "Don't run `overcommit-hook` directly; it is intended to be symlinked " \
+       "by each hook in a repository's .git/hooks directory."
+  exit 64 # EX_USAGE
+end
+
+# Check if Overcommit should invoke a Bundler context for loading gems
+require 'yaml'
+# rubocop:disable Style/RescueModifier
+if gemfile = YAML.load_file('.overcommit.yml')['gemfile'] rescue nil
+  ENV['BUNDLE_GEMFILE'] = gemfile
+  require 'bundler'
+
+  begin
+    Bundler.setup
+  rescue Bundler::BundlerError => ex
+    puts "Problem loading '#{gemfile}': #{ex.message}"
+    puts "Try running:\nbundle install --gemfile=#{gemfile}" if ex.is_a?(Bundler::GemNotFound)
+    exit 78 # EX_CONFIG
+  end
+end
+# rubocop:enable Style/RescueModifier
+
+begin
+  require 'overcommit'
+rescue LoadError
+  if gemfile
+    puts 'You have specified the `gemfile` option in your Overcommit ' \
+         'configuration but have not added the `overcommit` gem to ' \
+         "#{gemfile}."
+  else
+    puts 'This repository contains hooks installed by Overcommit, but the ' \
+         "`overcommit` gem is not installed.\n" \
+         'Install it with `gem install overcommit`.'
+  end
+
+  exit 64 # EX_USAGE
+end
+
+begin
+  logger = Overcommit::Logger.new(STDOUT)
+  Overcommit::Utils.log = logger
+
+  # Ensure master hook is up-to-date
+  installer = Overcommit::Installer.new(logger)
+  if installer.run(Overcommit::Utils.repo_root, action: :update)
+    exec($0, *ARGV) # Execute the updated hook with all original arguments
+  end
+
+  config = Overcommit::ConfigurationLoader.new(logger).load_repo_config
+
+  context = Overcommit::HookContext.create(hook_type, config, ARGV, STDIN)
+  config.apply_environment!(context, ENV)
+
+  printer = Overcommit::Printer.new(config, logger, context)
+  runner = Overcommit::HookRunner.new(config, logger, context, printer)
+
+  status = runner.run
+
+  exit(status ? 0 : 65) # 65 = EX_DATAERR
+rescue Overcommit::Exceptions::ConfigurationError => error
+  puts error
+  exit 78 # EX_CONFIG
+rescue Overcommit::Exceptions::HookContextLoadError => error
+  puts error
+  puts 'Are you running an old version of Overcommit?'
+  exit 69 # EX_UNAVAILABLE
+rescue Overcommit::Exceptions::HookLoadError,
+       Overcommit::Exceptions::InvalidHookDefinition => error
+  puts error.message
+  puts error.backtrace
+  exit 78 # EX_CONFIG
+rescue Overcommit::Exceptions::HookSetupFailed,
+       Overcommit::Exceptions::HookCleanupFailed => error
+  puts error.message
+  exit 74 # EX_IOERR
+rescue Overcommit::Exceptions::HookCancelled
+  puts 'You cancelled the hook run'
+  exit 130 # Ctrl-C cancel
+rescue Overcommit::Exceptions::InvalidGitRepo => error
+  puts error
+  exit 64 # EX_USAGE
+rescue Overcommit::Exceptions::ConfigurationSignatureChanged => error
+  puts error
+  puts "For more information, see #{Overcommit::REPO_URL}#security"
+  exit 1
+rescue Overcommit::Exceptions::InvalidHookSignature
+  exit 1
+rescue => error
+  puts error.message
+  puts error.backtrace
+  puts "Report this bug at #{Overcommit::BUG_REPORT_URL}"
+  exit 70 # EX_SOFTWARE
+end

template-dir/hooks/commit-msg

@@ -0,0 +1,115 @@
+#!/usr/bin/env ruby
+
+# Entrypoint for Overcommit hook integration. Installing Overcommit will result
+# in all of your git hooks being symlinked to this file, allowing the framework
+# to manage your hooks for you.
+
+# Prevent a Ruby stack trace from appearing when we interrupt the hook.
+# Note that this will be overridden when Overcommit is loaded, since the
+# InterruptHandler will redefine the trap at that time.
+Signal.trap('INT') do
+  puts 'Hook run interrupted'
+  exit 130
+end
+
+# Allow hooks to be disabled via environment variable so git commands can be run
+# in scripts without Overcommit running hooks
+if ENV['OVERCOMMIT_DISABLE'].to_i != 0 || ENV['OVERCOMMIT_DISABLED'].to_i != 0
+  exit
+end
+
+hook_type = File.basename($0)
+if hook_type == 'overcommit-hook'
+  puts "Don't run `overcommit-hook` directly; it is intended to be symlinked " \
+       "by each hook in a repository's .git/hooks directory."
+  exit 64 # EX_USAGE
+end
+
+# Check if Overcommit should invoke a Bundler context for loading gems
+require 'yaml'
+# rubocop:disable Style/RescueModifier
+if gemfile = YAML.load_file('.overcommit.yml')['gemfile'] rescue nil
+  ENV['BUNDLE_GEMFILE'] = gemfile
+  require 'bundler'
+
+  begin
+    Bundler.setup
+  rescue Bundler::BundlerError => ex
+    puts "Problem loading '#{gemfile}': #{ex.message}"
+    puts "Try running:\nbundle install --gemfile=#{gemfile}" if ex.is_a?(Bundler::GemNotFound)
+    exit 78 # EX_CONFIG
+  end
+end
+# rubocop:enable Style/RescueModifier
+
+begin
+  require 'overcommit'
+rescue LoadError
+  if gemfile
+    puts 'You have specified the `gemfile` option in your Overcommit ' \
+         'configuration but have not added the `overcommit` gem to ' \
+         "#{gemfile}."
+  else
+    puts 'This repository contains hooks installed by Overcommit, but the ' \
+         "`overcommit` gem is not installed.\n" \
+         'Install it with `gem install overcommit`.'
+  end
+
+  exit 64 # EX_USAGE
+end
+
+begin
+  logger = Overcommit::Logger.new(STDOUT)
+  Overcommit::Utils.log = logger
+
+  # Ensure master hook is up-to-date
+  installer = Overcommit::Installer.new(logger)
+  if installer.run(Overcommit::Utils.repo_root, action: :update)
+    exec($0, *ARGV) # Execute the updated hook with all original arguments
+  end
+
+  config = Overcommit::ConfigurationLoader.new(logger).load_repo_config
+
+  context = Overcommit::HookContext.create(hook_type, config, ARGV, STDIN)
+  config.apply_environment!(context, ENV)
+
+  printer = Overcommit::Printer.new(config, logger, context)
+  runner = Overcommit::HookRunner.new(config, logger, context, printer)
+
+  status = runner.run
+
+  exit(status ? 0 : 65) # 65 = EX_DATAERR
+rescue Overcommit::Exceptions::ConfigurationError => error
+  puts error
+  exit 78 # EX_CONFIG
+rescue Overcommit::Exceptions::HookContextLoadError => error
+  puts error
+  puts 'Are you running an old version of Overcommit?'
+  exit 69 # EX_UNAVAILABLE
+rescue Overcommit::Exceptions::HookLoadError,
+       Overcommit::Exceptions::InvalidHookDefinition => error
+  puts error.message
+  puts error.backtrace
+  exit 78 # EX_CONFIG
+rescue Overcommit::Exceptions::HookSetupFailed,
+       Overcommit::Exceptions::HookCleanupFailed => error
+  puts error.message
+  exit 74 # EX_IOERR
+rescue Overcommit::Exceptions::HookCancelled
+  puts 'You cancelled the hook run'
+  exit 130 # Ctrl-C cancel
+rescue Overcommit::Exceptions::InvalidGitRepo => error
+  puts error
+  exit 64 # EX_USAGE
+rescue Overcommit::Exceptions::ConfigurationSignatureChanged => error
+  puts error
+  puts "For more information, see #{Overcommit::REPO_URL}#security"
+  exit 1
+rescue Overcommit::Exceptions::InvalidHookSignature
+  exit 1
+rescue => error
+  puts error.message
+  puts error.backtrace
+  puts "Report this bug at #{Overcommit::BUG_REPORT_URL}"
+  exit 70 # EX_SOFTWARE
+end