Use the version's origin if the zone doesn't have one yet. [#766]absolute_origin_zone_txn_fix

3 files changed, 35 insertions, 3 deletions

diff --git a/dns/transaction.py b/dns/transaction.py
index ae7417e..846db4e 100644
--- a/dns/transaction.py
+++ b/dns/transaction.py
@@ -389,7 +389,7 @@ class Transaction:
             if rdataset.rdclass != self.manager.get_class():
                 raise ValueError(f'{method} has objects of wrong RdataClass')
             if rdataset.rdtype == dns.rdatatype.SOA:
-                (_, _, origin) = self.manager.origin_information()
+                (_, _, origin) = self._origin_information()
                 if name != origin:
                     raise ValueError(f'{method} has non-origin SOA')
             self._raise_if_not_empty(method, args)
@@ -585,3 +585,12 @@ class Transaction:
         Returns a node or ``None``.
         """
         raise NotImplementedError  # pragma: no cover
+
+    #
+    # Low-level API with a default implementation, in case a subclass needs
+    # to override.
+    #
+
+    def _origin_information(self):
+        # This is only used by _add()
+        return self.manager.origin_information()
diff --git a/dns/zone.py b/dns/zone.py
index 2e73144..69c3a73 100644
--- a/dns/zone.py
+++ b/dns/zone.py
@@ -870,10 +870,14 @@ class Version:
 
     def _validate_name(self, name):
         if name.is_absolute():
-            if not name.is_subdomain(self.zone.origin):
+            if self.origin is None:
+                # This should probably never happen as other code (e.g.
+                # _rr_line) will notice the lack of an origin before us, but
+                # we check just in case!
+                raise KeyError('no zone origin is defined')
+            if not name.is_subdomain(self.origin):
                 raise KeyError("name is not a subdomain of the zone origin")
             if self.zone.relativize:
-                # XXXRTH should it be an error if self.origin is still None?
                 name = name.relativize(self.origin)
         return name
 
@@ -1030,6 +1034,18 @@ class Transaction(dns.transaction.Transaction):
     def _get_node(self, name):
         return self.version.get_node(name)
 
+    def _origin_information(self):
+        (absolute, relativize, effective) = self.manager.origin_information()
+        if absolute is None and self.version.origin is not None:
+            # No origin has been committed yet, but we've learned one as part of
+            # this txn.  Use it.
+            absolute = self.version.origin
+            if relativize:
+                effective = dns.name.empty
+            else:
+                effective = absolute
+        return (absolute, relativize, effective)
+
 
 def from_text(text, origin=None, rdclass=dns.rdataclass.IN,
               relativize=True, zone_factory=Zone, filename=None,
diff --git a/tests/test_zone.py b/tests/test_zone.py
index bdc99a3..d0765df 100644
--- a/tests/test_zone.py
+++ b/tests/test_zone.py
@@ -1012,6 +1012,13 @@ class VersionedZoneTestCase(unittest.TestCase):
             rds = txn.get('example.', 'soa')
             self.assertEqual(rds[0].serial, 1)
 
+    def testNoRelativizeReaderOriginInText(self):
+        z = dns.zone.from_text(example_text, relativize=False,
+                               zone_factory=dns.versioned.Zone)
+        with z.reader(serial=1) as txn:
+            rds = txn.get('example.', 'soa')
+            self.assertEqual(rds[0].serial, 1)
+
     def testCnameAndOtherDataAddOther(self):
         z = dns.zone.from_text(example_cname, 'example.', relativize=True,
                                zone_factory=dns.versioned.Zone)