Add rst-lint pre-commit hook

config/default.yml

@@ -566,6 +566,13 @@ PreCommit:
       - '**/Gemfile'
       - '**/Rakefile'
 
+  RstLint:
+    enabled: false
+    description: 'Analyze reStructuredText files with rst-lint'
+    required_executable: 'rst-lint'
+    install_command: 'pip install restructuredtext_lint'
+    include: '**/*.rst'
+
   RuboCop:
     enabled: false
     description: 'Analyze with RuboCop'

lib/overcommit/hook/pre_commit/rst_lint.rb

@@ -0,0 +1,25 @@
+module Overcommit::Hook::PreCommit
+  # Runs `rst-lint` against any modified reStructuredText files
+  #
+  # @see https://github.com/twolfson/restructuredtext-lint
+  class RstLint < Base
+    MESSAGE_REGEX = /
+    ^(?<type>INFO|WARNING|ERROR|SEVERE)(?<file>(?:\w:)?[^:]+):(?<line>\d+)\s(?<msg>.+)
+    /x
+
+    def run
+      result = execute(command, args: applicable_files)
+      output = result.stdout.chomp
+
+      return :pass if result.success?
+      return [:fail, result.stderr] unless result.stderr.empty?
+
+      # example message:
+      # WARNING README.rst:7 Title underline too short.
+      extract_messages(
+        output.split("\n"),
+        MESSAGE_REGEX
+      )
+    end
+  end
+end

spec/overcommit/hook/pre_commit/rst_lint_spec.rb

@@ -0,0 +1,41 @@
+require 'spec_helper'
+
+describe Overcommit::Hook::PreCommit::RstLint do
+  let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
+  let(:context) { double('context') }
+  subject { described_class.new(config, context) }
+
+  let(:result) { double('result') }
+
+  before do
+    result.stub(success?: success, stdout: stdout, stderr: stderr)
+    subject.stub(:applicable_files).and_return(%w[file1.rst file2.rst])
+    subject.stub(:execute).and_return(result)
+  end
+
+  context 'when rst-lint exits successfully' do
+    let(:success) { true }
+    let(:stdout) { '' }
+    let(:stderr) { '' }
+
+    it { should pass }
+  end
+
+  context 'when rst-lint exits unsuccessfully' do
+    let(:success) { false }
+
+    context 'and it reports an error' do
+      let(:stdout) { 'WARNING file1.rst:7 Title underline too short.' }
+      let(:stderr) { '' }
+
+      it { should fail_hook }
+    end
+
+    context 'when there is an error running rst-lint' do
+      let(:stdout) { '' }
+      let(:stderr) { 'Some runtime error' }
+
+      it { should fail_hook }
+    end
+  end
+end