From 70854f222d35779bd18f7cdec35c5532e1f2a274 Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Sat, 4 Nov 2017 20:09:50 -0200
Subject: [PATCH 1/8] Add prepare-commit-msg hook

---
 .../hook/prepare_commit_msg/base.rb           |  11 ++
 .../hook_context/prepare_commit_msg.rb        |  26 ++++
 .../hook_context/prepare_commit_msg_spec.rb   |  38 ++++++
 spec/overcommit/utils_spec.rb                 |   4 +-
 template-dir/hooks/prepare-commit-msg         | 115 ++++++++++++++++++
 5 files changed, 192 insertions(+), 2 deletions(-)
 create mode 100644 lib/overcommit/hook/prepare_commit_msg/base.rb
 create mode 100644 lib/overcommit/hook_context/prepare_commit_msg.rb
 create mode 100644 spec/overcommit/hook_context/prepare_commit_msg_spec.rb
 create mode 100755 template-dir/hooks/prepare-commit-msg

diff --git a/lib/overcommit/hook/prepare_commit_msg/base.rb b/lib/overcommit/hook/prepare_commit_msg/base.rb
new file mode 100644
index 00000000..8b9f7901
--- /dev/null
+++ b/lib/overcommit/hook/prepare_commit_msg/base.rb
@@ -0,0 +1,11 @@
+require 'forwardable'
+
+module Overcommit::Hook::PrepareCommitMsg
+  # Functionality common to all prepare-commit-msg hooks.
+  class Base < Overcommit::Hook::Base
+    extend Forwardable
+
+    def_delegators :@context,
+                   :commit_msg_filename, :commit_msg_source, :commit
+  end
+end
diff --git a/lib/overcommit/hook_context/prepare_commit_msg.rb b/lib/overcommit/hook_context/prepare_commit_msg.rb
new file mode 100644
index 00000000..d50efd47
--- /dev/null
+++ b/lib/overcommit/hook_context/prepare_commit_msg.rb
@@ -0,0 +1,26 @@
+module Overcommit::HookContext
+  # Contains helpers related to contextual information used by prepare-commit-msg
+  # hooks.
+  class PrepareCommitMsg < Base
+    # Returns the name of the file that contains the commit log message
+    def commit_msg_filename
+      @args[0]
+    end
+
+    # Returns the source of the commit message, and can be: message (if a -m or
+    # -F option was given); template (if a -t option was given or the
+    # configuration option commit.template is set); merge (if the commit is a
+    # merge or a .git/MERGE_MSG file exists); squash (if a .git/SQUASH_MSG file
+    # exists); or commit, followed by a commit SHA-1 (if a -c, -C or --amend
+    # option was given)
+    def commit_msg_source
+      (@args[1] || 'commit').to_sym
+    end
+
+    # Returns the commit's SHA-1.
+    # If commit_msg_source is :commit, it's passed through the command-line.
+    def commit
+      @args[2] || `git rev-parse HEAD`
+    end
+  end
+end
diff --git a/spec/overcommit/hook_context/prepare_commit_msg_spec.rb b/spec/overcommit/hook_context/prepare_commit_msg_spec.rb
new file mode 100644
index 00000000..e664bba6
--- /dev/null
+++ b/spec/overcommit/hook_context/prepare_commit_msg_spec.rb
@@ -0,0 +1,38 @@
+require 'spec_helper'
+require 'overcommit/hook_context/prepare_commit_msg'
+
+describe Overcommit::HookContext::PrepareCommitMsg do
+  let(:config) { double('config') }
+  let(:args) { [commit_msg_filename, commit_msg_source] }
+  let(:commit_msg_filename) { 'message-template.txt' }
+  let(:commit_msg_source) { :file }
+  let(:commit) { 'SHA-1 here' }
+  let(:input) { double('input') }
+  let(:context) { described_class.new(config, args, input) }
+
+  describe '#commit_msg_filename' do
+    subject { context.commit_msg_filename }
+
+    it { should == commit_msg_filename }
+  end
+
+  describe '#commit_msg_source' do
+    subject { context.commit_msg_source }
+
+    it { should == commit_msg_source }
+  end
+
+  describe '#commit' do
+    subject { context.commit }
+
+    context "source isn't :commit" do
+      it { should == `git rev-parse HEAD` }
+    end
+
+    context 'source is :commit' do
+      let(:args) { [commit_msg_filename, :commit, commit] }
+
+      it { should == commit }
+    end
+  end
+end
diff --git a/spec/overcommit/utils_spec.rb b/spec/overcommit/utils_spec.rb
index 4a39d1a9..76272cdb 100644
--- a/spec/overcommit/utils_spec.rb
+++ b/spec/overcommit/utils_spec.rb
@@ -118,7 +118,7 @@
     subject { described_class.supported_hook_types }
 
     # rubocop:disable Metrics/LineLength
-    it { should =~ %w[commit-msg pre-commit post-checkout post-commit post-merge post-rewrite pre-push pre-rebase] }
+    it { should =~ %w[commit-msg pre-commit post-checkout post-commit post-merge post-rewrite pre-push pre-rebase prepare-commit-msg] }
     # rubocop:enable Metrics/LineLength
   end
 
@@ -126,7 +126,7 @@
     subject { described_class.supported_hook_type_classes }
 
     # rubocop:disable Metrics/LineLength
-    it { should =~ %w[CommitMsg PreCommit PostCheckout PostCommit PostMerge PostRewrite PrePush PreRebase] }
+    it { should =~ %w[CommitMsg PreCommit PostCheckout PostCommit PostMerge PostRewrite PrePush PreRebase PrepareCommitMsg] }
     # rubocop:enable Metrics/LineLength
   end
 
diff --git a/template-dir/hooks/prepare-commit-msg b/template-dir/hooks/prepare-commit-msg
new file mode 100755
index 00000000..3010ef7a
--- /dev/null
+++ b/template-dir/hooks/prepare-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 copied from 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

From 6004e53980d033d976a1384f5d4004e62e5ca1d6 Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Sat, 4 Nov 2017 20:49:19 -0200
Subject: [PATCH 2/8] This commit adds the ReplaceBranch prepare-commit-msg
 hook, which, when correctly configured, automatically generates a commit
 message template based on the branch name.

Groups captured in the branch_pattern regex can be used in replacement_text;
see the accompanying spec for details. Also, replacement_text can be a path to
a file, whose text will be processed following the same rules.
---
 config/default.yml                            | 14 +++++
 .../hook/prepare_commit_msg/replace_branch.rb | 54 +++++++++++++++++
 .../prepare_commit_msg/replace_branch_spec.rb | 59 +++++++++++++++++++
 3 files changed, 127 insertions(+)
 create mode 100644 lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
 create mode 100644 spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb

diff --git a/config/default.yml b/config/default.yml
index bfc73020..dcf7f96d 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -1143,6 +1143,20 @@ PostRewrite:
       - 'package.json'
       - 'yarn.lock'
 
+# Hooks that run during the `prepare-commit-msg` hook.
+PrepareCommitMsg:
+  ALL:
+    requires_files: false
+    required: false
+    quiet: false
+
+  ReplaceBranch:
+    enabled: false
+    description: 'Prepends the commit message with text based on the branch name'
+    branch_pattern: '\A.*\w+[-_](\d+).*\z'
+    replacement_text: '[#\1] [ci skip]'
+    on_fail: warn
+
 # Hooks that run during `git push`, after remote refs have been updated but
 # before any objects have been transferred.
 PrePush:
diff --git a/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb b/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
new file mode 100644
index 00000000..ae7a9696
--- /dev/null
+++ b/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
@@ -0,0 +1,54 @@
+module Overcommit::Hook::PrepareCommitMsg
+  # Prepends the commit message with a message based on the branch name.
+  # It's possible to reference parts of the branch name through the captures in
+  # the `branch_pattern` regex.
+  class ReplaceBranch < Base
+    def run
+      return :pass unless commit_msg_source == :commit
+      Overcommit::Utils.log.debug(
+        "Checking if '#{Overcommit::GitRepo.current_branch}' matches #{branch_pattern}"
+      )
+      if branch_pattern.match(Overcommit::GitRepo.current_branch)
+        prepend_commit_message
+        :pass
+      else
+        :warn
+      end
+    end
+
+    def prepend_commit_message
+      Overcommit::Utils.log.debug("Writing #{commit_msg_filename} with #{new_template}")
+      old_contents = File.read(commit_msg_filename)
+      File.open(commit_msg_filename, 'w') do |commit_file|
+        commit_file.write "#{new_template}\n#{old_contents}"
+      end
+    end
+
+    def new_template
+      @new_template ||= Overcommit::GitRepo.current_branch.gsub(branch_pattern, replacement_text)
+    end
+
+    def branch_pattern
+      @branch_pattern ||=
+        begin
+          pattern = config['branch_pattern']
+          Regexp.new((pattern || '').empty? ? '\A.*\w+[-_](\d+).*\z' : pattern)
+        end
+    end
+
+    def replacement_text
+      @replacement_text ||=
+        begin
+          if File.exist?(replacement_text_config)
+            File.read(replacement_text_config)
+          else
+            replacement_text_config
+          end
+        end
+    end
+
+    def replacement_text_config
+      @replacement_text_config ||= config['replacement_text']
+    end
+  end
+end
diff --git a/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
new file mode 100644
index 00000000..24659dba
--- /dev/null
+++ b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
@@ -0,0 +1,59 @@
+require 'spec_helper'
+
+describe Overcommit::Hook::PrepareCommitMsg::ReplaceBranch do
+  let(:config) { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+
+  subject(:hook) { described_class.new(config, context) }
+
+  before do
+    # stubbing this so we don't litter this repo with useless template files /
+    # configurations
+    hook.stub(:prepend_commit_message)
+    context.stub(:commit_msg_source).and_return(:commit)
+    allow(Overcommit::Utils).to receive_message_chain(:log, :debug)
+    allow(Overcommit::GitRepo).to receive(:current_branch).and_return(new_head)
+  end
+
+  let(:new_head) { 'userbeforeid-12345-branch-description' }
+
+  describe '#run' do
+    context 'when the checked out branch matches the pattern' do
+      it { is_expected.to pass }
+
+      context 'template contents' do
+        subject(:template) { hook.new_template }
+
+        before do
+          hook.stub(:replacement_text).and_return('Id is: \1')
+        end
+
+        it { is_expected.to eq('Id is: 12345') }
+      end
+    end
+
+    context 'when the checked out branch does not match the pattern' do
+      let(:new_head) { "this shouldn't match the default pattern" }
+
+      it { is_expected.to warn }
+    end
+  end
+
+  describe '#replacement_text' do
+    subject(:replacement_text) { hook.replacement_text }
+    let(:replacement_template_file) { 'valid_filename.txt' }
+    let(:replacement) { 'Id is: \1' }
+
+    context 'when the replacement text points to a valid filename' do
+      before do
+        hook.stub(:replacement_text_config).and_return(replacement_template_file)
+        File.stub(:exist?).and_return(true)
+        File.stub(:read).with(replacement_template_file).and_return(replacement)
+      end
+
+      describe 'it reads it as the replacement template' do
+        it { is_expected.to eq(replacement) }
+      end
+    end
+  end
+end

From 225b7d171bd871677f6a241e0703fe56860d9fd0 Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Sun, 30 Sep 2018 13:39:37 -0300
Subject: [PATCH 3/8] Address code review comments relating to concurrency and
 default.yml config file

---
 config/default.yml                            |  2 +-
 .../hook/prepare_commit_msg/base.rb           | 14 +++++-
 .../hook_context/prepare_commit_msg.rb        | 14 +++---
 .../hook/prepare_commit_msg/base_spec.rb      | 45 +++++++++++++++++++
 4 files changed, 68 insertions(+), 7 deletions(-)
 create mode 100644 spec/overcommit/hook/prepare_commit_msg/base_spec.rb

diff --git a/config/default.yml b/config/default.yml
index dcf7f96d..6d86e30e 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -1154,7 +1154,7 @@ PrepareCommitMsg:
     enabled: false
     description: 'Prepends the commit message with text based on the branch name'
     branch_pattern: '\A.*\w+[-_](\d+).*\z'
-    replacement_text: '[#\1] [ci skip]'
+    replacement_text: '[#\1]'
     on_fail: warn
 
 # Hooks that run during `git push`, after remote refs have been updated but
diff --git a/lib/overcommit/hook/prepare_commit_msg/base.rb b/lib/overcommit/hook/prepare_commit_msg/base.rb
index 8b9f7901..c278b5a6 100644
--- a/lib/overcommit/hook/prepare_commit_msg/base.rb
+++ b/lib/overcommit/hook/prepare_commit_msg/base.rb
@@ -6,6 +6,18 @@ class Base < Overcommit::Hook::Base
     extend Forwardable
 
     def_delegators :@context,
-                   :commit_msg_filename, :commit_msg_source, :commit
+                   :commit_message_filename, :commit_message_source, :commit, :lock
+
+    def modify_commit_message
+      raise 'This expects a block!' unless block_given?
+      # NOTE: this assumes all the hooks of the same type share the context's
+      # memory. If that's not the case, this won't work.
+      lock.synchronize do
+        contents = File.read(commit_message_filename)
+        File.open(commit_message_filename, 'w') do |f|
+          f << (yield contents)
+        end
+      end
+    end
   end
 end
diff --git a/lib/overcommit/hook_context/prepare_commit_msg.rb b/lib/overcommit/hook_context/prepare_commit_msg.rb
index d50efd47..93039a3c 100644
--- a/lib/overcommit/hook_context/prepare_commit_msg.rb
+++ b/lib/overcommit/hook_context/prepare_commit_msg.rb
@@ -3,7 +3,7 @@ module Overcommit::HookContext
   # hooks.
   class PrepareCommitMsg < Base
     # Returns the name of the file that contains the commit log message
-    def commit_msg_filename
+    def commit_message_filename
       @args[0]
     end
 
@@ -13,14 +13,18 @@ def commit_msg_filename
     # merge or a .git/MERGE_MSG file exists); squash (if a .git/SQUASH_MSG file
     # exists); or commit, followed by a commit SHA-1 (if a -c, -C or --amend
     # option was given)
-    def commit_msg_source
-      (@args[1] || 'commit').to_sym
+    def commit_message_source
+      @args[1].to_sym if @args[1]
     end
 
     # Returns the commit's SHA-1.
-    # If commit_msg_source is :commit, it's passed through the command-line.
-    def commit
+    # If commit_message_source is :commit, it's passed through the command-line.
+    def commit_message_source_ref
       @args[2] || `git rev-parse HEAD`
     end
+
+    def lock
+      @lock ||= Monitor.new
+    end
   end
 end
diff --git a/spec/overcommit/hook/prepare_commit_msg/base_spec.rb b/spec/overcommit/hook/prepare_commit_msg/base_spec.rb
new file mode 100644
index 00000000..e155313f
--- /dev/null
+++ b/spec/overcommit/hook/prepare_commit_msg/base_spec.rb
@@ -0,0 +1,45 @@
+require 'spec_helper'
+require 'overcommit/hook_context/prepare_commit_msg'
+
+describe Overcommit::Hook::PrepareCommitMsg::Base do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { Overcommit::HookContext::PrepareCommitMsg.new(config, [], StringIO.new) }
+  let(:printer) { double('printer') }
+
+  context 'when multiple hooks run simultaneously' do
+    let(:hook_1) { described_class.new(config, context) }
+    let(:hook_2) { described_class.new(config, context) }
+
+    let(:tempfile) { 'test-prepare-commit-msg.txt' }
+
+    let(:initial_content) { "This is a test\n" }
+
+    before do
+      File.open(tempfile, 'w') do |f|
+        f << initial_content
+      end
+    end
+
+    after do
+      File.delete(tempfile)
+    end
+
+    it 'works well with concurrency' do
+      allow(context).to receive(:commit_msg_filename).and_return(tempfile)
+      allow(hook_1).to receive(:run) do
+        hook_1.modify_commit_message do |contents|
+          "alpha\n" + contents
+        end
+      end
+      allow(hook_2).to receive(:run) do
+        hook_2.modify_commit_message do |contents|
+          contents + "bravo\n"
+        end
+      end
+      Thread.new { hook_1.run }
+      Thread.new { hook_2.run }
+      Thread.list.each { |t| t.join unless t == Thread.current }
+      expect(File.read(tempfile)).to match(/alpha\n#{initial_content}bravo\n/m)
+    end
+  end
+end

From 8f2b48a415cfb8d9d223953f1cd53c977bb9166a Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Sun, 30 Sep 2018 13:54:11 -0300
Subject: [PATCH 4/8] Updating ReplaceBranch hook

---
 .../hook/prepare_commit_msg/replace_branch.rb | 16 ++++------
 .../hook_context/prepare_commit_msg.rb        |  2 ++
 .../prepare_commit_msg/replace_branch_spec.rb | 18 ++++++++---
 .../hook_context/prepare_commit_msg_spec.rb   | 32 ++++++-------------
 4 files changed, 30 insertions(+), 38 deletions(-)

diff --git a/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb b/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
index ae7a9696..fdcd2cbb 100644
--- a/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
+++ b/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
@@ -4,26 +4,22 @@ module Overcommit::Hook::PrepareCommitMsg
   # the `branch_pattern` regex.
   class ReplaceBranch < Base
     def run
-      return :pass unless commit_msg_source == :commit
+      return :pass unless commit_message_source.empty? ||
+        commit_message_source == :commit # NOTE: avoid 'merge' and 'rebase'
       Overcommit::Utils.log.debug(
         "Checking if '#{Overcommit::GitRepo.current_branch}' matches #{branch_pattern}"
       )
       if branch_pattern.match(Overcommit::GitRepo.current_branch)
-        prepend_commit_message
+        Overcommit::Utils.log.debug("Writing #{commit_message_filename} with #{new_template}")
+        modify_commit_message do |old_contents|
+          "#{new_template}\n#{old_contents}"
+        end
         :pass
       else
         :warn
       end
     end
 
-    def prepend_commit_message
-      Overcommit::Utils.log.debug("Writing #{commit_msg_filename} with #{new_template}")
-      old_contents = File.read(commit_msg_filename)
-      File.open(commit_msg_filename, 'w') do |commit_file|
-        commit_file.write "#{new_template}\n#{old_contents}"
-      end
-    end
-
     def new_template
       @new_template ||= Overcommit::GitRepo.current_branch.gsub(branch_pattern, replacement_text)
     end
diff --git a/lib/overcommit/hook_context/prepare_commit_msg.rb b/lib/overcommit/hook_context/prepare_commit_msg.rb
index 93039a3c..d5bbf993 100644
--- a/lib/overcommit/hook_context/prepare_commit_msg.rb
+++ b/lib/overcommit/hook_context/prepare_commit_msg.rb
@@ -23,6 +23,8 @@ def commit_message_source_ref
       @args[2] || `git rev-parse HEAD`
     end
 
+    # Lock for the pre_commit_message file. Should be shared by all
+    # prepare-commit-message hooks
     def lock
       @lock ||= Monitor.new
     end
diff --git a/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
index 24659dba..a139142d 100644
--- a/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
+++ b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
@@ -1,20 +1,28 @@
 require 'spec_helper'
+require 'overcommit/hook_context/prepare_commit_msg'
 
 describe Overcommit::Hook::PrepareCommitMsg::ReplaceBranch do
   let(:config) { Overcommit::ConfigurationLoader.default_configuration }
-  let(:context) { double('context') }
+  let(:context) do
+    Overcommit::HookContext::PrepareCommitMsg.new(
+      config, [prepare_commit_message_file, 'commit'], StringIO.new
+    )
+  end
+
+  let(:prepare_commit_message_file) { 'prepare_commit_message_file' }
 
   subject(:hook) { described_class.new(config, context) }
 
   before do
-    # stubbing this so we don't litter this repo with useless template files /
-    # configurations
-    hook.stub(:prepend_commit_message)
-    context.stub(:commit_msg_source).and_return(:commit)
+    File.open(prepare_commit_message_file, 'w')
     allow(Overcommit::Utils).to receive_message_chain(:log, :debug)
     allow(Overcommit::GitRepo).to receive(:current_branch).and_return(new_head)
   end
 
+  after do
+    File.delete(prepare_commit_message_file)
+  end
+
   let(:new_head) { 'userbeforeid-12345-branch-description' }
 
   describe '#run' do
diff --git a/spec/overcommit/hook_context/prepare_commit_msg_spec.rb b/spec/overcommit/hook_context/prepare_commit_msg_spec.rb
index e664bba6..9371fe6c 100644
--- a/spec/overcommit/hook_context/prepare_commit_msg_spec.rb
+++ b/spec/overcommit/hook_context/prepare_commit_msg_spec.rb
@@ -3,36 +3,22 @@
 
 describe Overcommit::HookContext::PrepareCommitMsg do
   let(:config) { double('config') }
-  let(:args) { [commit_msg_filename, commit_msg_source] }
-  let(:commit_msg_filename) { 'message-template.txt' }
-  let(:commit_msg_source) { :file }
+  let(:args) { [commit_message_filename, commit_message_source] }
+  let(:commit_message_filename) { 'message-template.txt' }
+  let(:commit_message_source) { :file }
   let(:commit) { 'SHA-1 here' }
   let(:input) { double('input') }
   let(:context) { described_class.new(config, args, input) }
 
-  describe '#commit_msg_filename' do
-    subject { context.commit_msg_filename }
+  describe '#commit_message_filename' do
+    subject { context.commit_message_filename }
 
-    it { should == commit_msg_filename }
+    it { should == commit_message_filename }
   end
 
-  describe '#commit_msg_source' do
-    subject { context.commit_msg_source }
+  describe '#commit_message_source' do
+    subject { context.commit_message_source }
 
-    it { should == commit_msg_source }
-  end
-
-  describe '#commit' do
-    subject { context.commit }
-
-    context "source isn't :commit" do
-      it { should == `git rev-parse HEAD` }
-    end
-
-    context 'source is :commit' do
-      let(:args) { [commit_msg_filename, :commit, commit] }
-
-      it { should == commit }
-    end
+    it { should == commit_message_source }
   end
 end

From 4aa26d67c610b5692f330f70334872d284e3f21a Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Sun, 30 Sep 2018 14:08:14 -0300
Subject: [PATCH 5/8] Fixing CI errors

---
 spec/overcommit/hook/prepare_commit_msg/base_spec.rb | 2 +-
 template-dir/hooks/prepare-commit-msg                | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/spec/overcommit/hook/prepare_commit_msg/base_spec.rb b/spec/overcommit/hook/prepare_commit_msg/base_spec.rb
index e155313f..fffa2a43 100644
--- a/spec/overcommit/hook/prepare_commit_msg/base_spec.rb
+++ b/spec/overcommit/hook/prepare_commit_msg/base_spec.rb
@@ -25,7 +25,7 @@
     end
 
     it 'works well with concurrency' do
-      allow(context).to receive(:commit_msg_filename).and_return(tempfile)
+      allow(context).to receive(:commit_message_filename).and_return(tempfile)
       allow(hook_1).to receive(:run) do
         hook_1.modify_commit_message do |contents|
           "alpha\n" + contents
diff --git a/template-dir/hooks/prepare-commit-msg b/template-dir/hooks/prepare-commit-msg
index 3010ef7a..b345d9c7 100755
--- a/template-dir/hooks/prepare-commit-msg
+++ b/template-dir/hooks/prepare-commit-msg
@@ -107,7 +107,7 @@ rescue Overcommit::Exceptions::ConfigurationSignatureChanged => error
   exit 1
 rescue Overcommit::Exceptions::InvalidHookSignature
   exit 1
-rescue => error
+rescue StandardError => error
   puts error.message
   puts error.backtrace
   puts "Report this bug at #{Overcommit::BUG_REPORT_URL}"

From ae2d529218eb0460adb3a33b8618ca6d9e46e0b4 Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Sun, 30 Sep 2018 14:16:00 -0300
Subject: [PATCH 6/8] Hopefully fixing Appveyor windows build

---
 .../hook/prepare_commit_msg/replace_branch_spec.rb       | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
index a139142d..74967141 100644
--- a/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
+++ b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
@@ -9,7 +9,14 @@
     )
   end
 
-  let(:prepare_commit_message_file) { 'prepare_commit_message_file' }
+  let(:prepare_commit_message_file) do
+    basename = 'prepare_commit_message_file.txt'
+    if Overcommit::OS.windows?
+      ENV.fetch('APPVEYOR_BUILD_FOLDER', '.') + Overcommit::OS::SEPARATOR + basename
+    else
+      basename
+    end
+  end
 
   subject(:hook) { described_class.new(config, context) }
 

From 5e338e7cc917850f3b62ea4204eaf921b47ba488 Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Sun, 30 Sep 2018 18:58:01 -0300
Subject: [PATCH 7/8] Not removing test file in Appveyor due to build errors

---
 .../hook/prepare_commit_msg/replace_branch_spec.rb    | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
index 74967141..ad3fd2d0 100644
--- a/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
+++ b/spec/overcommit/hook/prepare_commit_msg/replace_branch_spec.rb
@@ -9,14 +9,7 @@
     )
   end
 
-  let(:prepare_commit_message_file) do
-    basename = 'prepare_commit_message_file.txt'
-    if Overcommit::OS.windows?
-      ENV.fetch('APPVEYOR_BUILD_FOLDER', '.') + Overcommit::OS::SEPARATOR + basename
-    else
-      basename
-    end
-  end
+  let(:prepare_commit_message_file) { 'prepare_commit_message_file.txt' }
 
   subject(:hook) { described_class.new(config, context) }
 
@@ -27,7 +20,7 @@
   end
 
   after do
-    File.delete(prepare_commit_message_file)
+    File.delete(prepare_commit_message_file) unless ENV['APPVEYOR']
   end
 
   let(:new_head) { 'userbeforeid-12345-branch-description' }

From 9ae0dc4ffdd585cebc3d9186e944aa8ac545b3f8 Mon Sep 17 00:00:00 2001
From: Daniel Luna <dancluna@gmail.com>
Date: Mon, 1 Oct 2018 15:00:01 -0300
Subject: [PATCH 8/8] Fixing replace_branch with the new commit_message_source
 API

---
 lib/overcommit/hook/prepare_commit_msg/replace_branch.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb b/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
index fdcd2cbb..8a5c1f82 100644
--- a/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
+++ b/lib/overcommit/hook/prepare_commit_msg/replace_branch.rb
@@ -4,7 +4,7 @@ module Overcommit::Hook::PrepareCommitMsg
   # the `branch_pattern` regex.
   class ReplaceBranch < Base
     def run
-      return :pass unless commit_message_source.empty? ||
+      return :pass unless !commit_message_source ||
         commit_message_source == :commit # NOTE: avoid 'merge' and 'rebase'
       Overcommit::Utils.log.debug(
         "Checking if '#{Overcommit::GitRepo.current_branch}' matches #{branch_pattern}"