From: Gord Thompson <gord@gordthompson.com>
Date: Fri, 20 Oct 2023 14:19:42 +0000 (-0600)
Subject: Fix identity column reflection failure
X-Git-Tag: rel_1_4_50~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9ea0bb11d9bb947c525c6c6ecc0320c47e93d893;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

Fix identity column reflection failure

Fixes: #10504

Fix reflection failure for bigint identity column with
a large identity start value (more than 18 digits).

Change-Id: I8a7ec114e4596b1710d789a4a4fb08013edd80ce
(cherry picked from commit 4c46ed6a9f6f93abd5abe5ba4b95c4c1e8f52a4c)
---

diff --git a/doc/build/changelog/unreleased_14/10504.rst b/doc/build/changelog/unreleased_14/10504.rst
new file mode 100644
index 0000000000..7afc00f667
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/10504.rst
@@ -0,0 +1,8 @@
+.. change::
+    :tags: bug, mssql, reflection
+    :tickets: 10504
+    :versions: 2.0.23
+
+    Fixed issue where identity column reflection would fail
+    for a bigint column with a large identity start value
+    (more than 18 digits).
diff --git a/lib/sqlalchemy/dialects/mssql/information_schema.py b/lib/sqlalchemy/dialects/mssql/information_schema.py
index 8ca95d79b5..998757c170 100644
--- a/lib/sqlalchemy/dialects/mssql/information_schema.py
+++ b/lib/sqlalchemy/dialects/mssql/information_schema.py
@@ -215,7 +215,7 @@ class IdentitySqlVariant(TypeDecorator):
     cache_ok = True
 
     def column_expression(self, colexpr):
-        return cast(colexpr, Numeric)
+        return cast(colexpr, Numeric(38, 0))
 
 
 identity_columns = Table(
diff --git a/test/dialect/mssql/test_reflection.py b/test/dialect/mssql/test_reflection.py
index d24ee4adb9..125959cf9d 100644
--- a/test/dialect/mssql/test_reflection.py
+++ b/test/dialect/mssql/test_reflection.py
@@ -847,7 +847,11 @@ class IdentityReflectionTest(fixtures.TablesTest):
                     ),
                 ),
                 Column("id2", Integer, Identity()),
-                Column("id3", sqltypes.BigInteger, Identity()),
+                Column(
+                    "id3",
+                    sqltypes.BigInteger,
+                    Identity(start=-9223372036854775808),
+                ),
                 Column("id4", sqltypes.SmallInteger, Identity()),
                 Column("id5", sqltypes.Numeric, Identity()),
             ]
@@ -869,7 +873,10 @@ class IdentityReflectionTest(fixtures.TablesTest):
                 eq_(type(col["identity"]["start"]), int)
                 eq_(type(col["identity"]["increment"]), int)
             elif col["name"] == "id3":
-                eq_(col["identity"], {"start": 1, "increment": 1})
+                eq_(
+                    col["identity"],
+                    {"start": -9223372036854775808, "increment": 1},
+                )
                 eq_(type(col["identity"]["start"]), util.compat.long_type)
                 eq_(type(col["identity"]["increment"]), util.compat.long_type)
             elif col["name"] == "id4":