Merge ~wgrant/turnip:pygit2-0.27.4 into turnip:master

[William Grant]

Upgrade to pygit2 0.27.4.

This fixes pygit2 #839, so we can remove our workaround and also stop
crashing on mis-encoded signatures.

0.27.4 helpfully removed the long-deprecated Reference.get_object(), so
use peel() instead.

LP: #1815517

[Colin Watson (cjwatson)]

review: Approve

diff --git a/requirements.txt b/requirements.txt
index 6d50d36..b706f3c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -33,7 +33,7 @@ pyasn1==0.1.7
 pycparser==2.10
 pycrypto==2.6.1
 pyflakes==0.8.1
-pygit2==0.27.2
+pygit2==0.27.4
 pyramid==1.5.4
 python-mimeparse==0.1.4
 # XXX: deryck 2012-08-10
diff --git a/setup.py b/setup.py
index c7ccd2a..24ef980 100755
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@ requires = [
     'cornice',
     'lazr.sshserver>=0.1.7',
     'Paste',
-    'pygit2>=0.27.2,<0.28.0',
+    'pygit2>=0.27.4,<0.28.0',
     'python-openid',
     'PyYAML',
     'Twisted[conch]',
diff --git a/turnip/api/store.py b/turnip/api/store.py
index 650a3d8..499182e 100644
--- a/turnip/api/store.py
+++ b/turnip/api/store.py
@@ -55,20 +55,9 @@ def format_commit(git_object):
         raise GitError('Invalid type: object {} is not a commit.'.format(
             git_object.oid.hex))
     parents = [parent.hex for parent in git_object.parent_ids]
-    # XXX cjwatson 2018-11-15: A regression in pygit2 0.27.1 means that we
-    # have to decode the commit message ourselves.  See:
-    #   https://github.com/libgit2/pygit2/issues/839
-    if git_object.message_encoding is not None:
-        message = git_object.raw_message.decode(
-            encoding=git_object.message_encoding, errors="strict")
-    else:
-        # If the encoding is not explicit, it may not be UTF-8, so it is not
-        # safe to decode it strictly.
-        message = git_object.raw_message.decode(
-            encoding="UTF-8", errors="replace")
     return {
         'sha1': git_object.oid.hex,
-        'message': message,
+        'message': git_object.message,
         'author': format_signature(git_object.author),
         'committer': format_signature(git_object.committer),
         'parents': parents,
diff --git a/turnip/api/tests/test_api.py b/turnip/api/tests/test_api.py
index f435d75..303a84b 100644
--- a/turnip/api/tests/test_api.py
+++ b/turnip/api/tests/test_api.py
@@ -204,7 +204,7 @@ class ApiTestCase(TestCase):
         self.assertTrue(ref in body)
         self.assertTrue(self.tag.get('ref') in body)
 
-        oid = repo.head.get_object().oid.hex  # git object sha
+        oid = repo.head.peel().oid.hex  # git object sha
         resp_sha = body[ref]['object'].get('sha1')
         self.assertEqual(oid, resp_sha)
 
diff --git a/turnip/api/tests/test_helpers.py b/turnip/api/tests/test_helpers.py
index 28ed9df..bf55b2e 100644
--- a/turnip/api/tests/test_helpers.py
+++ b/turnip/api/tests/test_helpers.py
@@ -132,7 +132,7 @@ class RepoFactory(object):
     def generate_tags(self, num_tags):
         """Generate n number of tags."""
         repo = self.repo
-        oid = repo.head.get_object().oid
+        oid = repo.head.peel().oid
         for i in range(num_tags):
             self.add_tag('tag{}'.format(i), 'tag message {}'.format(i), oid)