GitRepository.has_feature: capture stderr

to avoid spurious output on the console and add the error message to the
exception intead.

2 files changed, 6 insertions, 3 deletions

diff --git a/gbp/git/repository.py b/gbp/git/repository.py
index 78d8701..8f87854 100644
--- a/gbp/git/repository.py
+++ b/gbp/git/repository.py
@@ -188,9 +188,12 @@ class GitRepository(object):
         @rtype: C{bool}
         """
         args = GitArgs(command, '-m')
-        help, foo, ret = self._git_inout('help', args.args)
+        help, stderr, ret = self._git_inout('help',
+                                           args.args,
+                                           capture_stderr=True)
         if ret:
-            raise GitRepositoryError("Invalid git command: %s" % command)
+            raise GitRepositoryError("Invalid git command '%s': %s"
+                                     % (command, stderr[:-1]))
 
         # Parse git command man page
         section_re = re.compile(r'^(?P<section>[A-Z].*)')
diff --git a/tests/test_GitRepository.py b/tests/test_GitRepository.py
index 7365dd8..bec0836 100644
--- a/tests/test_GitRepository.py
+++ b/tests/test_GitRepository.py
@@ -828,7 +828,7 @@ def test_cmd_has_feature():
     >>> repo._cmd_has_feature("foobarcmd", "foobaroption")
     Traceback (most recent call last):
     ...
-    GitRepositoryError: Invalid git command: foobarcmd
+    GitRepositoryError: Invalid git command 'foobarcmd': No manual entry for gitfoobarcmd
     >>> repo._cmd_has_feature("show", "standard-notes")
     True
     >>> repo._cmd_has_feature("show", "no-standard-notes")