Add handle of git scissors cleanup and custom comment char (#34)

* Add handle of git cutline

Git commit command has `cleanup` argument (
https://git-scm.com/docs/git-commit#git-commit---cleanupltmodegt)
which can clean up commit messages after some cutline.

This cutline appears when you make commit with
git commit -v
(-v, --verbose add diff to commit message)

This commit add cutting of commit message after this cutline

* Add handle of custom commentchar

Git has oppurtunity to set custom comment char.
Add retriving this char from config and handle on message parsing

* Add non-commented text after cutline in sample

Suggested by @jorisroovers to properly test use-case for git scissors
line since commented lines are being ignored regardless.

gitlint/git.py

@@ -31,13 +31,26 @@ def git_version():
     return version
 
 
+def git_commentchar():
+    """ Shortcut for retrieving comment char from git config
+    """
+    try:
+        commentchar = ustr(sh.git.config('--get', 'core.commentchar')).replace(u"\n", u"")
+    except sh.ErrorReturnCode_1:  # pylint: disable=no-member
+        # exception means that default commentchar used
+        commentchar = '#'
+    return commentchar
+
+
 class GitCommitMessage(object):
     """ Class representing a git commit message. A commit message consists of the following:
       - original: The actual commit message as returned by `git log`
       - full: original, but stripped of any comments
       - title: the first line of full
       - body: all lines following the title
     """
+    COMMENT_CHAR = git_commentchar()
+    CUTLINE = '{0} ------------------------ >8 ------------------------'.format(COMMENT_CHAR)
 
     def __init__(self, original=None, full=None, title=None, body=None):
         self.original = original
@@ -48,7 +61,12 @@ def __init__(self, original=None, full=None, title=None, body=None):
     @staticmethod
     def from_full_message(commit_msg_str):
         """  Parses a full git commit message by parsing a given string into the different parts of a commit message """
-        lines = [line for line in commit_msg_str.splitlines() if not line.startswith("#")]
+        all_lines = commit_msg_str.splitlines()
+        try:
+            cutline_index = all_lines.index(GitCommitMessage.CUTLINE)
+        except ValueError:
+            cutline_index = None
+        lines = [line for line in all_lines[:cutline_index] if not line.startswith(GitCommitMessage.COMMENT_CHAR)]
         full = "\n".join(lines)
         title = lines[0] if len(lines) > 0 else ""
         body = lines[1:] if len(lines) > 1 else []

gitlint/tests/samples/commit_message/sample1

@@ -4,3 +4,11 @@ This is the first line of the commit message body and it is meant to test a line
 This line has a tråiling space. 
 This line has a trailing tab.	
 # This is a cömmented  line
+# ------------------------ >8 ------------------------
+# Anything after this line should be cleaned up
+# this line appears on `git commit -v` command
+diff --git a/gitlint/tests/samples/commit_message/sample1 b/gitlint/tests/samples/commit_message/sample1
+index 82dbe7f..ae71a14 100644
+--- a/gitlint/tests/samples/commit_message/sample1
++++ b/gitlint/tests/samples/commit_message/sample1
+@@ -1 +1 @@

gitlint/tests/test_git.py

@@ -2,7 +2,7 @@
 
 import datetime
 import dateutil
-from mock import patch, call
+from mock import patch, call, PropertyMock
 from sh import ErrorReturnCode, CommandNotFound
 
 from gitlint.tests.base import BaseTestCase
@@ -126,7 +126,18 @@ def test_from_commit_msg_full(self):
                          u"This line has a tråiling space. ",
                          "This line has a trailing tab.\t"]
         expected_full = expected_title + "\n" + "\n".join(expected_body)
-        expected_original = expected_full + u"\n# This is a cömmented  line\n"
+        expected_original = expected_full + (
+            u"\n# This is a cömmented  line\n"
+            u"# ------------------------ >8 ------------------------\n"
+            u"# Anything after this line should be cleaned up\n"
+            u"# this line appears on `git commit -v` command\n"
+            u"diff --git a/gitlint/tests/samples/commit_message/sample1 "
+            u"b/gitlint/tests/samples/commit_message/sample1\n"
+            u"index 82dbe7f..ae71a14 100644\n"
+            u"--- a/gitlint/tests/samples/commit_message/sample1\n"
+            u"+++ b/gitlint/tests/samples/commit_message/sample1\n"
+            u"@@ -1 +1 @@\n"
+        )
 
         commit = gitcontext.commits[-1]
         self.assertEqual(commit.message.title, expected_title)
@@ -226,3 +237,17 @@ def test_gitcommit_equality(self):
             self.assertNotEqual(commit1, commit2)
             setattr(commit1, attr, prev_val)
             self.assertEqual(commit1, commit2)
+
+    @patch('gitlint.git.sh')
+    def test_custom_commitchar(self, sh):
+        sh.git.config.return_value = ';'
+        from gitlint.git import GitCommitMessage  # pylint: disable=redefined-outer-name,reimported
+
+        with patch.object(GitCommitMessage, 'COMMENT_CHAR', new_callable=PropertyMock) as commit_char_mock:
+            commit_char_mock.return_value = ';'
+            message = GitCommitMessage.from_full_message(u"Tïtle\n\nBödy 1\n;Cömment\nBody 2")
+
+        self.assertEqual(message.title, u"Tïtle")
+        self.assertEqual(message.body, ["", u"Bödy 1", "Body 2"])
+        self.assertEqual(message.full, u"Tïtle\n\nBödy 1\nBody 2")
+        self.assertEqual(message.original, u"Tïtle\n\nBödy 1\n;Cömment\nBody 2")