diff --git a/python/mozversioncontrol/mozversioncontrol/__init__.py b/python/mozversioncontrol/mozversioncontrol/__init__.py
index 35cc425a09cc..282f3269dade 100644
--- a/python/mozversioncontrol/mozversioncontrol/__init__.py
+++ b/python/mozversioncontrol/mozversioncontrol/__init__.py
@@ -64,6 +64,10 @@ class Repository(object):
         self.version = LooseVersion(match.group(1))
         return self.version
 
+    @abc.abstractproperty
+    def name(self):
+        """Name of the tool."""
+
     @abc.abstractmethod
     def get_modified_files(self):
         '''Return a list of files that are modified in this repository's
@@ -95,6 +99,10 @@ class HgRepository(Repository):
         super(HgRepository, self).__init__(path, tool=hg)
         self._env[b'HGPLAIN'] = b'1'
 
+    @property
+    def name(self):
+        return 'hg'
+
     def get_modified_files(self):
         # Use --no-status to print just the filename.
         return self._run('status', '--modified', '--no-status').splitlines()
@@ -123,6 +131,10 @@ class GitRepository(Repository):
     def __init__(self, path, git='git'):
         super(GitRepository, self).__init__(path, tool=git)
 
+    @property
+    def name(self):
+        return 'git'
+
     def get_modified_files(self):
         return self._run('diff', '--diff-filter=M', '--name-only').splitlines()
 
diff --git a/tools/mach_commands.py b/tools/mach_commands.py
index aa30473e3c36..9ff251c2a019 100644
--- a/tools/mach_commands.py
+++ b/tools/mach_commands.py
@@ -8,7 +8,6 @@ import sys
 import os
 import stat
 import platform
-import errno
 import re
 
 from mach.decorators import (
@@ -18,7 +17,6 @@ from mach.decorators import (
 )
 
 from mozbuild.base import MachCommandBase, MozbuildObject
-import mozversioncontrol
 
 
 @CommandProvider
@@ -263,7 +261,7 @@ class FormatProvider(MachCommandBase):
         # Note that this will potentially miss a lot things
         from subprocess import Popen, PIPE
 
-        if isinstance(self.repository, mozversioncontrol.HgRepository):
+        if self.repository.name == 'hg':
             diff_process = Popen(["hg", "diff", "-U0", "-r", ".^",
                                   "--include", "glob:**.c", "--include", "glob:**.cpp",
                                   "--include", "glob:**.h",
@@ -329,9 +327,10 @@ class FormatProvider(MachCommandBase):
         cf_process = Popen(args)
         if show:
             # show the diff
-            if isinstance(self.repository, mozversioncontrol.HgRepository):
+            if self.repository.name == 'hg':
                 cf_process = Popen(["hg", "diff"] + path_list)
             else:
+                assert self.repository.name == 'git'
                 cf_process = Popen(["git", "diff"] + path_list)
         return cf_process.communicate()[0]