Pass commit-msg hooks when commit message is empty

lib/overcommit/hook/commit_msg/base.rb

@@ -5,7 +5,8 @@ module Overcommit::Hook::CommitMsg
   class Base < Overcommit::Hook::Base
     extend Forwardable
 
-    def_delegators :@context, :commit_message, :update_commit_message,
-                   :commit_message_lines, :commit_message_file
+    def_delegators :@context, :empty_message?, :commit_message,
+                   :update_commit_message, :commit_message_lines,
+                   :commit_message_file
   end
 end

lib/overcommit/hook/commit_msg/capitalized_subject.rb

@@ -2,6 +2,8 @@ module Overcommit::Hook::CommitMsg
   # Ensures commit message subject lines start with a capital letter.
   class CapitalizedSubject < Base
     def run
+      return :pass if empty_message?
+
       first_letter = commit_message_lines[0].to_s.match(/^[[:punct:]]*(.)/)[1]
       unless first_letter.match(/[[:upper:]]/)
         return :warn, 'Subject should start with a capital letter'

lib/overcommit/hook/commit_msg/hard_tabs.rb

@@ -2,6 +2,8 @@ module Overcommit::Hook::CommitMsg
   # Checks for hard tabs in commit messages.
   class HardTabs < Base
     def run
+      return :pass if empty_message?
+
       # Catches hard tabs entered by the user (not auto-generated)
       if commit_message.index(/\t/)
         return :warn, "Don't use hard tabs in commit messages"

lib/overcommit/hook/commit_msg/single_line_subject.rb

@@ -2,6 +2,8 @@ module Overcommit::Hook::CommitMsg
   # Ensures commit message subject lines are followed by a blank line.
   class SingleLineSubject < Base
     def run
+      return :pass if empty_message?
+
       unless commit_message_lines[1].to_s.strip.empty?
         return :warn, 'Subject should be one line and followed by a blank line'
       end

lib/overcommit/hook/commit_msg/text_width.rb

@@ -3,6 +3,8 @@ module Overcommit::Hook::CommitMsg
   # under the preferred limits.
   class TextWidth < Base
     def run
+      return :pass if empty_message?
+
       @errors = []
 
       find_errors_in_subject(commit_message_lines.first)

lib/overcommit/hook/commit_msg/trailing_period.rb

@@ -2,6 +2,8 @@ module Overcommit::Hook::CommitMsg
   # Ensures commit message subject lines do not have a trailing period
   class TrailingPeriod < Base
     def run
+      return :pass if empty_message?
+
       if commit_message_lines.first.rstrip.end_with?('.')
         return :warn, 'Please omit trailing period from commit message subject'
       end

lib/overcommit/hook_context/commit_msg.rb

@@ -1,6 +1,10 @@
 module Overcommit::HookContext
   # Contains helpers related to contextual information used by commit-msg hooks.
   class CommitMsg < Base
+    def empty_message?
+      commit_message.strip.empty?
+    end
+
     # User commit message stripped of comments and diff (from verbose output).
     def commit_message
       commit_message_lines.join

spec/overcommit/hook/commit_msg/capitalized_subject_spec.rb

@@ -8,6 +8,13 @@
 
   before do
     subject.stub(:commit_message_lines).and_return(commit_msg.split("\n"))
+    subject.stub(:empty_message?).and_return(commit_msg.empty?)
+  end
+
+  context 'when commit message is empty' do
+    let(:commit_msg) { '' }
+
+    it { should pass }
   end
 
   context 'when subject starts with a capital letter' do

spec/overcommit/hook/commit_msg/hard_tabs_spec.rb

@@ -7,6 +7,13 @@
 
   before do
     subject.stub(:commit_message).and_return(commit_msg)
+    subject.stub(:empty_message?).and_return(commit_msg.empty?)
+  end
+
+  context 'when commit message is empty' do
+    let(:commit_msg) { '' }
+
+    it { should pass }
   end
 
   context 'when message contains hard tabs' do

spec/overcommit/hook/commit_msg/single_line_subject_spec.rb

@@ -7,6 +7,13 @@
 
   before do
     subject.stub(:commit_message_lines).and_return(commit_msg.split("\n"))
+    subject.stub(:empty_message?).and_return(commit_msg.empty?)
+  end
+
+  context 'when commit message is empty' do
+    let(:commit_msg) { '' }
+
+    it { should pass }
   end
 
   context 'when subject is separated from body by a blank line' do

spec/overcommit/hook/commit_msg/text_width_spec.rb

@@ -7,6 +7,13 @@
 
   before do
     subject.stub(:commit_message_lines).and_return(commit_msg.split("\n"))
+    subject.stub(:empty_message?).and_return(commit_msg.empty?)
+  end
+
+  context 'when commit message is empty' do
+    let(:commit_msg) { '' }
+
+    it { should pass }
   end
 
   context 'when subject is longer than 60 characters' do

spec/overcommit/hook/commit_msg/trailing_period_spec.rb

@@ -7,6 +7,13 @@
 
   before do
     subject.stub(:commit_message_lines).and_return(commit_msg.split("\n"))
+    subject.stub(:empty_message?).and_return(commit_msg.empty?)
+  end
+
+  context 'when commit message is empty' do
+    let(:commit_msg) { '' }
+
+    it { should pass }
   end
 
   context 'when subject contains a trailing period' do

spec/overcommit/hook_context/commit_msg_spec.rb

@@ -40,4 +40,26 @@
       subject.should == ["Some commit message\n"]
     end
   end
+
+  describe '#empty_message?' do
+    subject { context.empty_message? }
+
+    context 'when commit message is empty' do
+      let(:commit_msg) { [] }
+
+      it { should == true }
+    end
+
+    context 'when commit message contains only whitespace' do
+      let(:commit_msg) { [' '] }
+
+      it { should == true }
+    end
+
+    context 'when commit message is not empty' do
+      let(:commit_msg) { ['Some commit message'] }
+
+      it { should == false }
+    end
+  end
 end