Add version-specific behavior.

--progress is not a valid flag for earlier versions of git, so we check
for the version before using it.

git/cmd.py

@@ -41,7 +41,7 @@ class Git(object):
 		of the command to stdout.
 		Set its value to 'full' to see details about the returned values.
 	"""
-	__slots__ = ("_working_dir", "cat_file_all", "cat_file_header")
+	__slots__ = ("_working_dir", "cat_file_all", "cat_file_header", "_version")
 
 	# CONFIGURATION
 	# The size in bytes read from stdout when copying git's output to another stream
@@ -205,6 +205,7 @@ def __init__(self, working_dir=None):
 		   .git directory in case of bare repositories."""
 		super(Git, self).__init__()
 		self._working_dir = working_dir
+		self._version = self._get_version_as_tuple()
 
 		# cached command slots
 		self.cat_file_header = None
@@ -513,3 +514,13 @@ def clear_cache(self):
 		self.cat_file_all = None
 		self.cat_file_header = None
 		return self
+
+	def _get_version_as_tuple(self):
+		""" Get and parse git version string. """
+		version_str = self._call_process('version')
+		version_numbers = version_str.rpartition(' ')[2]
+		return tuple(version_numbers.split('.'))
+
+	@property
+	def version(self):
+		return self._version

git/remote.py

@@ -514,7 +514,8 @@ def fetch(self, refspec=None, progress=None, **kwargs):
 		:note:
 			As fetch does not provide progress information to non-ttys, we cannot make 
 			it available here unfortunately as in the 'push' method."""
-		proc = self.repo.git.fetch(self, refspec, with_extended_output=True, as_process=True, v=True, progress=True, **kwargs)
+		if self.repo.git.version >= (1, 7, 0, 0): kwargs['progress'] = True
+		proc = self.repo.git.fetch(self, refspec, with_extended_output=True, as_process=True, v=True, **kwargs)
 		return self._get_fetch_info_from_stderr(proc, progress or RemoteProgress())
 
 	def pull(self, refspec=None, progress=None, **kwargs):
@@ -525,7 +526,8 @@ def pull(self, refspec=None, progress=None, **kwargs):
 		:param progress: see 'push' method
 		:param kwargs: Additional arguments to be passed to git-pull
 		:return: Please see 'fetch' method """
-		proc = self.repo.git.pull(self, refspec, with_extended_output=True, as_process=True, v=True, progress=True, **kwargs)
+		if self.repo.git.version >= (1, 7, 0, 0): kwargs['progress'] = True
+		proc = self.repo.git.pull(self, refspec, with_extended_output=True, as_process=True, v=True, **kwargs)
 		return self._get_fetch_info_from_stderr(proc, progress or RemoteProgress())
 
 	def push(self, refspec=None, progress=None, **kwargs):
@@ -546,7 +548,8 @@ def push(self, refspec=None, progress=None, **kwargs):
 			in their flags.
 			If the operation fails completely, the length of the returned IterableList will
 			be null."""
-		proc = self.repo.git.push(self, refspec, porcelain=True, as_process=True, progress=True, **kwargs)
+		if self.repo.git.version >= (1, 7, 0, 0): kwargs['progress'] = True
+		proc = self.repo.git.push(self, refspec, porcelain=True, as_process=True, progress=True, v=True, **kwargs)
 		return self._get_push_info(proc, progress or RemoteProgress())
 
 	@property

git/repo/base.py

@@ -684,7 +684,8 @@ def _clone(cls, git, url, path, odb_default_type, progress, **kwargs):
 		# END windows handling 
 
 		try:
-			proc = git.clone(url, path, with_extended_output=True, as_process=True, v=True, progress=True, **kwargs)
+			if git.version >= (1, 7, 0, 0): kwargs['progress'] = True
+			proc = git.clone(url, path, with_extended_output=True, as_process=True, v=True, **kwargs)
 			if progress:
 				_digest_process_messages(proc.stderr, progress)
 			_finalize_proc(proc)