Align checking of identities with C git fsck.

dulwich/objects.py

@@ -202,16 +202,16 @@ def check_identity(identity, error_msg):
       identity: Identity string
       error_msg: Error message to use in exception
     """
-    email_start = identity.find(b"<")
-    email_end = identity.find(b">")
-    if (
-        email_start < 0
-        or email_end < 0
-        or email_end <= email_start
-        or identity.find(b"<", email_start + 1) >= 0
-        or identity.find(b">", email_end + 1) >= 0
-        or not identity.endswith(b">")
-    ):
+    email_start = identity.find(b'<')
+    email_end = identity.find(b'>')
+    if not all([
+        email_start >= 1,
+        identity[email_start - 1] == b' '[0],
+        identity.find(b'<', email_start + 1) == -1,
+        email_end == len(identity) - 1,
+        b'\0' not in identity,
+        b'\n' not in identity,
+    ]):
         raise ObjectFormatException(error_msg)
 
 

dulwich/tests/test_objects.py

@@ -1203,7 +1203,10 @@ class CheckTests(TestCase):
             b"Dave Borowitz <dborowitz@google.com>",
             "failed to check good identity",
         )
-        check_identity(b"<dborowitz@google.com>", "failed to check good identity")
+        check_identity(b" <dborowitz@google.com>", "failed to check good identity")
+        self.assertRaises(
+            ObjectFormatException, check_identity, b'<dborowitz@google.com>', 'no space before email'
+        )
         self.assertRaises(
             ObjectFormatException, check_identity, b"Dave Borowitz", "no email"
         )
@@ -1237,6 +1240,36 @@ class CheckTests(TestCase):
             b"Dave Borowitz <dborowitz@google.com>xxx",
             "trailing characters",
         )
+        self.assertRaises(
+            ObjectFormatException,
+            check_identity,
+            b"Dave Borowitz <dborowitz@google.com>xxx",
+            "trailing characters",
+        )
+        self.assertRaises(
+            ObjectFormatException,
+            check_identity,
+            b'Dave<Borowitz <dborowitz@google.com>',
+            'reserved byte in name',
+        )
+        self.assertRaises(
+            ObjectFormatException,
+            check_identity,
+            b'Dave>Borowitz <dborowitz@google.com>',
+            'reserved byte in name',
+        )
+        self.assertRaises(
+            ObjectFormatException,
+            check_identity,
+            b'Dave\0Borowitz <dborowitz@google.com>',
+            'null byte',
+        )
+        self.assertRaises(
+            ObjectFormatException,
+            check_identity,
+            b'Dave\nBorowitz <dborowitz@google.com>',
+            'newline byte',
+        )
 
 
 class TimezoneTests(TestCase):