Get system user id in a lazy manner

Calling getpass.getuser may lead to breakage in environments where there
is no entries in the /etc/passwd file for the current user.

Setting the environment variables for the git user configurations should
prevents GitPython from using values from /etc/passwd. However, doing so
will not prevent reading /etc/passwd and looking for an entry with the
current user UID.

This patch changes the behavior described above so GitPython will
perform a lazy evaluation of /etc/passwd, only doing so when the
environment variables for the git user configuration are not available.

Signed-off-by: Athos Ribeiro <athos@redhat.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/test/test_util.py b/test/test_util.py
index df4e5474..2f946891 100644
--- a/test/test_util.py
+++ b/test/test_util.py
@@ -4,10 +4,11 @@
 # This module is part of GitPython and is released under
 # the BSD License: http://www.opensource.org/licenses/bsd-license.php
 
+import os
 import pickle
 import tempfile
 import time
-from unittest import skipIf
+from unittest import mock, skipIf
 from datetime import datetime
 
 import ddt
@@ -215,6 +216,28 @@ class TestUtils(TestBase):
             self.assertIsInstance(Actor.author(cr), Actor)
         # END assure config reader is handled
 
+    @mock.patch("getpass.getuser")
+    def test_actor_get_uid_laziness_not_called(self, mock_get_uid):
+        env = {
+            "GIT_AUTHOR_NAME": "John Doe",
+            "GIT_AUTHOR_EMAIL": "jdoe@example.com",
+            "GIT_COMMITTER_NAME": "Jane Doe",
+            "GIT_COMMITTER_EMAIL": "jane@example.com",
+        }
+        os.environ.update(env)
+        for cr in (None, self.rorepo.config_reader()):
+            Actor.committer(cr)
+            Actor.author(cr)
+        self.assertFalse(mock_get_uid.called)
+
+    @mock.patch("getpass.getuser")
+    def test_actor_get_uid_laziness_called(self, mock_get_uid):
+        for cr in (None, self.rorepo.config_reader()):
+            Actor.committer(cr)
+            Actor.author(cr)
+        self.assertTrue(mock_get_uid.called)
+        self.assertEqual(mock_get_uid.call_count, 4)
+
     def test_actor_from_string(self):
         self.assertEqual(Actor._from_string("name"), Actor("name", None))
         self.assertEqual(Actor._from_string("name <>"), Actor("name", ""))