fix(repo): fail loudly if worktrees are used

As GitPython is in maintenance mode, there will be no new features.
However, I believe it's good idea to explicitly state we do not support
certain things if this is the case.

Therefore, when worktrees are encountered, we will throw an specific
exception to indicate that.

The current implementation is hacky to speed up development,
and increases the risk of failing due to false-positive worktree
directories.

Related to #344

1 files changed, 19 insertions, 1 deletions

diff --git a/git/test/test_repo.py b/git/test/test_repo.py
index c95592ea..2e44f0aa 100644
--- a/git/test/test_repo.py
+++ b/git/test/test_repo.py
@@ -33,7 +33,10 @@ from git import (
 )
 from git.repo.fun import touch
 from git.util import join_path_native
-from git.exc import BadObject
+from git.exc import (
+    BadObject,
+    WorkTreeRepositoryUnsupported
+)
 from gitdb.util import bin_to_hex
 from git.compat import string_types
 from gitdb.test.lib import with_rw_directory
@@ -45,6 +48,8 @@ import shutil
 import itertools
 from io import BytesIO
 
+from nose import SkipTest
+
 
 class TestRepo(TestBase):
 
@@ -779,3 +784,16 @@ class TestRepo(TestBase):
         self.assertFalse(repo.is_ancestor("master", c1))
         for i, j in itertools.permutations([c1, 'ffffff', ''], r=2):
             self.assertRaises(GitCommandError, repo.is_ancestor, i, j)
+
+    @with_rw_directory
+    def test_work_tree_unsupported(self, rw_dir):
+        git = Git(rw_dir)
+        if git.version_info[:3] < (2, 5, 1):
+            raise SkipTest("worktree feature unsupported")
+
+        rw_master = self.rorepo.clone(join_path_native(rw_dir, 'master_repo'))
+        rw_master.git.checkout('HEAD~10')
+        worktree_path = join_path_native(rw_dir, 'worktree_repo')
+        rw_master.git.worktree('add', worktree_path, 'master')
+
+        self.failUnlessRaises(WorkTreeRepositoryUnsupported, Repo, worktree_path)