From cdfd5f5e83ad86e78d6f9816f14d7139c12af769 Mon Sep 17 00:00:00 2001
From: Aidan Haran <aidanharan@yahoo.com>
Date: Fri, 18 Sep 2026 18:54:43 +0100
Subject: [PATCH] Add JSON schema cache serializer

Ref: https://github.com/rails/rails/pull/58769
---
 .../sqlserver/json_schema_cache_serializer.rb  | 18 ++++++++++++++++++
 .../sqlserver/sql_type_metadata.rb             |  8 ++++++++
 .../connection_adapters/sqlserver_adapter.rb   |  2 ++
 3 files changed, 28 insertions(+)
 create mode 100644 lib/active_record/connection_adapters/sqlserver/json_schema_cache_serializer.rb

diff --git a/lib/active_record/connection_adapters/sqlserver/json_schema_cache_serializer.rb b/lib/active_record/connection_adapters/sqlserver/json_schema_cache_serializer.rb
new file mode 100644
index 000000000..5960aec49
--- /dev/null
+++ b/lib/active_record/connection_adapters/sqlserver/json_schema_cache_serializer.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLServer
+      module JSONSchemaCacheSerializer
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_column", ActiveRecord::ConnectionAdapters::SQLServer::Column)
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_unicode_varchar", ActiveRecord::ConnectionAdapters::SQLServer::Type::UnicodeVarchar)
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_type_metadata", ActiveRecord::ConnectionAdapters::SQLServer::TypeMetadata)
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_datatime2", ActiveRecord::ConnectionAdapters::SQLServer::Type::DateTime2)
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_datetime", ActiveRecord::ConnectionAdapters::SQLServer::Type::DateTime)
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_time", ActiveRecord::ConnectionAdapters::SQLServer::Type::Time)
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_big_interger", ActiveRecord::ConnectionAdapters::SQLServer::Type::BigInteger)
+        ::ActiveRecord::ConnectionAdapters::JSONSchemaCacheSerializer.register("sqlserver_integer", ActiveRecord::ConnectionAdapters::SQLServer::Type::Integer)
+      end
+    end
+  end
+end
diff --git a/lib/active_record/connection_adapters/sqlserver/sql_type_metadata.rb b/lib/active_record/connection_adapters/sqlserver/sql_type_metadata.rb
index b3f1222d2..2fed18843 100644
--- a/lib/active_record/connection_adapters/sqlserver/sql_type_metadata.rb
+++ b/lib/active_record/connection_adapters/sqlserver/sql_type_metadata.rb
@@ -32,6 +32,14 @@ def hash
           [TypeMetadata, __getobj__, is_identity, is_primary, table_name, ordinal_position].hash
         end
 
+        def init_from_schema_json(coder, references)
+          @sql_type = coder["sql_type"]
+          @type = coder["type"]&.to_sym
+          @limit = coder["limit"]
+          @precision = coder["precision"]
+          @scale = coder["scale"]
+        end
+
         private
 
         def deduplicated
diff --git a/lib/active_record/connection_adapters/sqlserver_adapter.rb b/lib/active_record/connection_adapters/sqlserver_adapter.rb
index 03f542bd5..5b32e1ea0 100644
--- a/lib/active_record/connection_adapters/sqlserver_adapter.rb
+++ b/lib/active_record/connection_adapters/sqlserver_adapter.rb
@@ -29,6 +29,7 @@
 require "active_record/connection_adapters/sqlserver/quoting"
 require "active_record/connection_adapters/sqlserver/utils"
 require "active_record/connection_adapters/sqlserver_column"
+require "active_record/connection_adapters/sqlserver/json_schema_cache_serializer"
 require "active_record/tasks/sqlserver_database_tasks"
 
 module ActiveRecord
@@ -44,6 +45,7 @@ class SQLServerAdapter < AbstractAdapter
       include SQLServer::DatabaseStatements
       include SQLServer::Quoting
       include SQLServer::Version
+      include SQLServer::JSONSchemaCacheSerializer
 
       ADAPTER_NAME = "SQLServer"