From: Bryan Forbes <bryan@reigndropsfall.net>
Date: Thu, 15 Apr 2021 17:35:52 +0000 (-0500)
Subject: Derive `next_value.type` from `Sequence.data_type` if available
X-Git-Tag: rel_1_4_10~6^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=adc950945025d436ef97095b4e706700ebae34ff;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

Derive `next_value.type` from `Sequence.data_type` if available

Fixes #6287

Change-Id: I7d428ed86cd72cd910bfff9058a52c7fcb7c64ac
---

diff --git a/doc/build/changelog/unreleased_14/6287.rst b/doc/build/changelog/unreleased_14/6287.rst
new file mode 100644
index 0000000000..6dfc18319a
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/6287.rst
@@ -0,0 +1,7 @@
+.. change::
+    :tags: bug
+    :tickets: 6287
+    :versions: 1.4.9
+
+    Fixed a bug where ``sqlalchemy.sql.functions.next_value`` was not deriving
+    its ``type`` from the ``Sequence`` that created it.
diff --git a/lib/sqlalchemy/sql/functions.py b/lib/sqlalchemy/sql/functions.py
index d71926a1f9..02ed551001 100644
--- a/lib/sqlalchemy/sql/functions.py
+++ b/lib/sqlalchemy/sql/functions.py
@@ -1064,6 +1064,9 @@ class next_value(GenericFunction):
         ), "next_value() accepts a Sequence object as input."
         self._bind = self._get_bind(kw)
         self.sequence = seq
+        self.type = sqltypes.to_instance(
+            seq.data_type or getattr(self, "type", None)
+        )
 
     def compare(self, other, **kw):
         return (
diff --git a/test/sql/test_sequences.py b/test/sql/test_sequences.py
index dd8491d310..3b25ba2ad0 100644
--- a/test/sql/test_sequences.py
+++ b/test/sql/test_sequences.py
@@ -1,4 +1,5 @@
 import sqlalchemy as sa
+from sqlalchemy import BigInteger
 from sqlalchemy import Integer
 from sqlalchemy import MetaData
 from sqlalchemy import Sequence
@@ -387,6 +388,10 @@ class SequenceTest(fixtures.TestBase, testing.AssertsCompiledSQL):
         is_false(testing.db.dialect.has_table(connection, "table_1"))
         is_false(testing.db.dialect.has_table(connection, "table_2"))
 
+    def test_next_value_type(self):
+        seq = Sequence("my_sequence", data_type=BigInteger)
+        assert isinstance(seq.next_value().type, BigInteger)
+
 
 class FutureSequenceTest(fixtures.FutureEngineMixin, SequenceTest):
     __requires__ = ("sequences",)