From 6289902bbc615da71d68af7a69d6732dc4ad0b2d Mon Sep 17 00:00:00 2001
From: Castedo Ellerman <castedo@castedo.com>
Date: Sat, 16 Nov 2024 10:30:14 -0500
Subject: [PATCH] fix incorrect empty message commit serialization

* Fixes incorrect signature verification for commits with an empty message,
  as encoded by CGit (https://github.com/jelmer/dulwich/issues/1429)
---
 dulwich/objects.py             |  2 +-
 tests/compat/test_porcelain.py | 25 ++++++++++++++++++++++++-
 tests/test_objects.py          |  2 +-
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/dulwich/objects.py b/dulwich/objects.py
index 48d3712f9..03426eda1 100644
--- a/dulwich/objects.py
+++ b/dulwich/objects.py
@@ -728,8 +728,8 @@ def _format_message(headers, body):
         yield git_line(field, lines[0])
         for line in lines[1:]:
             yield b" " + line + b"\n"
+    yield b"\n"  # There must be a new line after the headers
     if body:
-        yield b"\n"  # There must be a new line after the headers
         yield body
 
 
diff --git a/tests/compat/test_porcelain.py b/tests/compat/test_porcelain.py
index f20d90016..003b9c43a 100644
--- a/tests/compat/test_porcelain.py
+++ b/tests/compat/test_porcelain.py
@@ -126,7 +126,6 @@ def test_verify(self):
                 "commit",
                 "--allow-empty",
                 "-S" + PorcelainGpgTestCase.DEFAULT_KEY_ID,
-                "--allow-empty-message",
                 "-m",
                 "foo",
             ],
@@ -139,3 +138,27 @@ def test_verify(self):
         commit = self.repo[b"HEAD"]
         self.assertNotEqual(commit.gpgsig, None)
         commit.verify()
+
+    def test_verify_with_empty_message(self):
+        # Test that CGit signatures can be verified by dulwich
+        self.import_default_key()
+
+        run_git_or_fail(
+            [
+                f"--git-dir={self.repo.controldir()}",
+                "commit",
+                "--allow-empty",
+                "-S" + PorcelainGpgTestCase.DEFAULT_KEY_ID,
+                "--allow-empty-message",
+                "-m",
+                "",
+            ],
+            env={
+                "GNUPGHOME": os.environ["GNUPGHOME"],
+                "GIT_COMMITTER_NAME": "Joe Example",
+                "GIT_COMMITTER_EMAIL": "joe@example.com",
+            },
+        )
+        commit = self.repo[b"HEAD"]
+        self.assertNotEqual(commit.gpgsig, None)
+        commit.verify()
diff --git a/tests/test_objects.py b/tests/test_objects.py
index 4be85dd3b..81f2190c7 100644
--- a/tests/test_objects.py
+++ b/tests/test_objects.py
@@ -1066,7 +1066,7 @@ def test_serialize_none_message(self):
                 b"type blob\n"
                 b"tag 0.1\n"
                 b"tagger Jelmer Vernooij <jelmer@samba.org> "
-                b"423423423 +0000\n"
+                b"423423423 +0000\n\n"
             ),
             x.as_raw_string(),
         )