Use git dir

xfel_calibrate/calibrate.py

@@ -118,7 +118,7 @@ def deconsolize_args(args):
 def extract_title_author_version(nb):
     """ Tries to extract title, author from markdown.
 
-    Version is taken from git.
+    The version is taken from git.
     """
 
     first_md = first_markdown_cell(nb)
@@ -130,8 +130,10 @@ def extract_title_author_version(nb):
     title = title[0] if len(title) else None
     author = author[0] if len(author) else None
 
-    chdir(os.path.dirname(__file__))
-    version = check_output(["git", 'describe', '--tag']).decode('utf8')
+    git_dir = '{}/../.git'.format(os.path.dirname(__file__))
+    version = check_output(['git',
+                            '--git-dir={}'.format(git_dir),
+                            'describe', '--tag']).decode('utf8')
     version = version.replace("\n", "")
     return title, author, version