RUBY-3620 - Sessions should ignore "cluster mismatched" validation and execute commands on other clusters

lib/mongo/client.rb

@@ -1318,7 +1318,11 @@ def do_close
     # @api private
     def get_session!(options = {})
       if options[:session]
-        return options[:session].validate!(self)
+        begin
+          return options[:session].validate!(self)
+        rescue Error::SessionClusterMismatched
+          nil # fall through to creating a new session
+        end
       end
 
       cluster.validate_session_support!(timeout: timeout_sec)

lib/mongo/error/session_cluster_mismatched.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+# rubocop:todo all
+
+# Copyright (C) 2017-2025 MongoDB Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module Mongo
+  class Error
+
+    # Error indicating that the session was retrieved from a client with a
+    # different cluster than that of the client through which it is currently being used.
+    class SessionClusterMismatched < InvalidSession
+
+      # Create the new exception.
+      #
+      # @example Create the new exception.
+      #   SessionClusterMismatched.new
+      def initialize
+        super('The configured cluster of the client used to create this session does not match that ' +
+                'of the client owning this operation. Please only use this session for operations ' +
+                'through its parent client.')
+      end
+    end
+  end
+end

lib/mongo/session.rb

@@ -289,14 +289,6 @@ def session_id
     # @api private
     attr_accessor :recovery_token
 
-    # Error message indicating that the session was retrieved from a client with a different cluster than that of the
-    # client through which it is currently being used.
-    #
-    # @since 2.5.0
-    MISMATCHED_CLUSTER_ERROR_MSG = 'The configuration of the client used to create this session does not match that ' +
-        'of the client owning this operation. Please only use this session for operations through its parent ' +
-        'client.'.freeze
-
     # Error message describing that the session cannot be used because it has already been ended.
     #
     # @since 2.5.0
@@ -1255,9 +1247,7 @@ def check_if_ended!
     end
 
     def check_matching_cluster!(client)
-      if @client.cluster != client.cluster
-        raise Mongo::Error::InvalidSession.new(MISMATCHED_CLUSTER_ERROR_MSG)
-      end
+      raise Mongo::Error::SessionClusterMismatched.new if @client.cluster != client.cluster
     end
 
     def check_transactions_supported!