From 9960d1f2e1998db9ecb7d57e777ff68c46cae512 Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 13:00:20 -0600
Subject: [PATCH 01/10] RUBY-3816 Remove instance_variable_set reach-ins in
 core types

Replace metaprogramming reach-ins that mutated another object's private
state with straightforward OO.

Cluster.create and Database.create only ever mutated the client they were
handed, via instance_variable_set, and were called only from Client#with.
Move that behavior onto Client as reset_cluster! and reset_database!, and
delete the two class factories.

Convert Message.deserialize_array and .deserialize_field from class methods
that set ivars on a passed-in message into instance methods, so the ivar
access is ordinary self-assignment. Update both call sites.
---
 lib/mongo/client.rb              | 29 +++++++++++++++++++++++++++--
 lib/mongo/cluster.rb             | 24 ------------------------
 lib/mongo/database.rb            | 18 ------------------
 lib/mongo/protocol/compressed.rb |  4 ++--
 lib/mongo/protocol/message.rb    | 22 ++++++++++------------
 5 files changed, 39 insertions(+), 58 deletions(-)

diff --git a/lib/mongo/client.rb b/lib/mongo/client.rb
index ed6044637e..ed857402aa 100644
--- a/lib/mongo/client.rb
+++ b/lib/mongo/client.rb
@@ -796,10 +796,10 @@ def use(name)
     def with(new_options = nil)
       clone.tap do |client|
         opts = client.update_options(new_options || Options::Redacted.new)
-        Database.create(client)
+        client.reset_database!
         # We can't use the same cluster if some options that would affect it
         # have changed.
-        Cluster.create(client, monitoring: opts[:monitoring]) if cluster_modifying?(opts)
+        client.reset_cluster!(monitoring: opts[:monitoring]) if cluster_modifying?(opts)
       end
     end
 
@@ -855,6 +855,31 @@ def update_options(new_options)
       end
     end
 
+    # Replaces this client's database with a fresh instance built from the
+    # client's current options. Used by #with so a reconfigured client does
+    # not share its database with the client it was cloned from.
+    #
+    # @api private
+    def reset_database!
+      @database = Database.new(self, options[:database], options)
+    end
+
+    # Replaces this client's cluster with a fresh instance built from the
+    # client's current options. Used by #with so a reconfigured client does
+    # not share its cluster with the client it was cloned from.
+    #
+    # @param [ Monitoring | nil ] monitoring The monitoring instance to use
+    #   with the new cluster. If nil, a new instance of Monitoring is created.
+    #
+    # @api private
+    def reset_cluster!(monitoring: nil)
+      @cluster = Cluster.new(
+        cluster.addresses.map(&:to_s),
+        monitoring || Monitoring.new,
+        cluster_options
+      )
+    end
+
     # Get the read concern for this client.
     #
     # @example Get the client read concern.
diff --git a/lib/mongo/cluster.rb b/lib/mongo/cluster.rb
index bb822eebfa..9752e96fe8 100644
--- a/lib/mongo/cluster.rb
+++ b/lib/mongo/cluster.rb
@@ -269,30 +269,6 @@ def initialize(seeds, monitoring, options = Options::Redacted.new)
       start_stop_srv_monitor
     end
 
-    # Create a cluster for the provided client, for use when we don't want the
-    # client's original cluster instance to be the same.
-    #
-    # @example Create a cluster for the client.
-    #   Cluster.create(client)
-    #
-    # @param [ Client ] client The client to create on.
-    # @param [ Monitoring | nil ] monitoring. The monitoring instance to use
-    #   with the new cluster. If nil, a new instance of Monitoring will be
-    #   created.
-    #
-    # @return [ Cluster ] The cluster.
-    #
-    # @since 2.0.0
-    # @api private
-    def self.create(client, monitoring: nil)
-      cluster = Cluster.new(
-        client.cluster.addresses.map(&:to_s),
-        monitoring || Monitoring.new,
-        client.cluster_options
-      )
-      client.instance_variable_set(:@cluster, cluster)
-    end
-
     # @return [ Hash ] The options hash.
     attr_reader :options
 
diff --git a/lib/mongo/database.rb b/lib/mongo/database.rb
index b22dc5daeb..deaf88d132 100644
--- a/lib/mongo/database.rb
+++ b/lib/mongo/database.rb
@@ -644,24 +644,6 @@ def watch(pipeline = [], options = {})
       )
     end
 
-    # Create a database for the provided client, for use when we don't want the
-    # client's original database instance to be the same.
-    #
-    # @api private
-    #
-    # @example Create a database for the client.
-    #   Database.create(client)
-    #
-    # @param [ Client ] client The client to create on.
-    #
-    # @return [ Database ] The database.
-    #
-    # @since 2.0.0
-    def self.create(client)
-      database = Database.new(client, client.options[:database], client.options)
-      client.instance_variable_set(:@database, database)
-    end
-
     # @return [ Integer | nil ] Operation timeout that is for this database or
     #   for the corresponding client.
     #
diff --git a/lib/mongo/protocol/compressed.rb b/lib/mongo/protocol/compressed.rb
index 7e586116a1..1aa221abaa 100644
--- a/lib/mongo/protocol/compressed.rb
+++ b/lib/mongo/protocol/compressed.rb
@@ -95,9 +95,9 @@ def maybe_inflate
 
         message.send(:fields).each do |field|
           if field[:multi]
-            Message.deserialize_array(message, buf, field)
+            message.deserialize_array(buf, field)
           else
-            Message.deserialize_field(message, buf, field)
+            message.deserialize_field(buf, field)
           end
         end
         message.fix_after_deserialization if message.is_a?(Msg)
diff --git a/lib/mongo/protocol/message.rb b/lib/mongo/protocol/message.rb
index c67388d69b..a2d0938ece 100644
--- a/lib/mongo/protocol/message.rb
+++ b/lib/mongo/protocol/message.rb
@@ -270,9 +270,9 @@ def self.deserialize(io,
         message = Registry.get(_op_code).allocate
         message.send(:fields).each do |field|
           if field[:multi]
-            deserialize_array(message, buf, field, options)
+            message.deserialize_array(buf, field, options)
           else
-            deserialize_field(message, buf, field, options)
+            message.deserialize_field(buf, field, options)
           end
         end
         message.fix_after_deserialization if message.is_a?(Msg)
@@ -369,7 +369,6 @@ def self.field(name, type, multi = false)
       # deserialized field specified in the class by the field dsl under
       # the key +:multi+
       #
-      # @param message [Message] Message to contain the deserialized array.
       # @param io [IO] Stream containing the array to deserialize.
       # @param field [Hash] Hash representing a field.
       # @param options [ Hash ]
@@ -377,18 +376,17 @@ def self.field(name, type, multi = false)
       # @option options [ Boolean ] :deserialize_as_bson Whether to deserialize
       #   each of the elements in this array using BSON types wherever possible.
       #
-      # @return [Message] Message with deserialized array.
+      # @return [Array] The deserialized array.
       # @api private
-      def self.deserialize_array(message, io, field, options = {})
+      def deserialize_array(io, field, options = {})
         elements = []
-        count = message.instance_variable_get(field[:multi])
+        count = instance_variable_get(field[:multi])
         count.times { elements << field[:type].deserialize(io, options) }
-        message.instance_variable_set(field[:name], elements)
+        instance_variable_set(field[:name], elements)
       end
 
-      # Deserializes a single field in a message
+      # Deserializes a single field into this message.
       #
-      # @param message [Message] Message to contain the deserialized field.
       # @param io [IO] Stream containing the field to deserialize.
       # @param field [Hash] Hash representing a field.
       # @param options [ Hash ]
@@ -396,10 +394,10 @@ def self.deserialize_array(message, io, field, options = {})
       # @option options [ Boolean ] :deserialize_as_bson Whether to deserialize
       #   this field using BSON types wherever possible.
       #
-      # @return [Message] Message with deserialized field.
+      # @return [Object] The deserialized field value.
       # @api private
-      def self.deserialize_field(message, io, field, options = {})
-        message.instance_variable_set(
+      def deserialize_field(io, field, options = {})
+        instance_variable_set(
           field[:name],
           field[:type].deserialize(io, options)
         )

From 841f86749c40b4be0d854d25241924e921b0df2f Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 13:18:12 -0600
Subject: [PATCH 02/10] RUBY-3816 Replace send with public_send/direct calls on
 public methods

Several sites used Object#send to invoke methods that are already public,
which needlessly bypasses method visibility and hides intent. Switch them
to public_send, or to a direct call where the method name is a literal.

No behavior change: every affected method is public.
---
 lib/mongo/bulk_write/result_combiner.rb | 2 +-
 lib/mongo/cluster/sdam_flow.rb          | 4 ++--
 lib/mongo/crypt/handle.rb               | 2 +-
 lib/mongo/cursor.rb                     | 2 +-
 lib/mongo/options/redacted.rb           | 4 ++--
 lib/mongo/socket/ssl.rb                 | 4 ++--
 6 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/lib/mongo/bulk_write/result_combiner.rb b/lib/mongo/bulk_write/result_combiner.rb
index 8c27eb3cf0..8337b62c03 100644
--- a/lib/mongo/bulk_write/result_combiner.rb
+++ b/lib/mongo/bulk_write/result_combiner.rb
@@ -92,7 +92,7 @@ def result
 
       def combine_counts!(result)
         Result::FIELDS.each do |field|
-          if result.respond_to?(field) && (value = result.send(field))
+          if result.respond_to?(field) && (value = result.public_send(field))
             results.merge!(field => (results[field] || 0) + value)
           end
         end
diff --git a/lib/mongo/cluster/sdam_flow.rb b/lib/mongo/cluster/sdam_flow.rb
index 794e2dad72..921b8cecf9 100644
--- a/lib/mongo/cluster/sdam_flow.rb
+++ b/lib/mongo/cluster/sdam_flow.rb
@@ -385,7 +385,7 @@ def update_rs_without_primary
     def add_servers_from_desc(updated_desc)
       added_servers = []
       %w[hosts passives arbiters].each do |m|
-        updated_desc.send(m).each do |address_str|
+        updated_desc.public_send(m).each do |address_str|
           if (server = cluster.add(address_str, monitor: false))
             added_servers << server
           end
@@ -402,7 +402,7 @@ def add_servers_from_desc(updated_desc)
     # good primary).
     def remove_servers_not_in_desc(updated_desc)
       updated_desc_address_strs = %w[hosts passives arbiters].map do |m|
-        updated_desc.send(m)
+        updated_desc.public_send(m)
       end.flatten
       servers_list.each do |server|
         next if updated_desc_address_strs.include?(address_str = server.address.to_s)
diff --git a/lib/mongo/crypt/handle.rb b/lib/mongo/crypt/handle.rb
index a149182f85..0ecff0b38d 100644
--- a/lib/mongo/crypt/handle.rb
+++ b/lib/mongo/crypt/handle.rb
@@ -203,7 +203,7 @@ def set_bypass_query_analysis
       # Send the logs from libmongocrypt to the Mongo::Logger
       def set_logger_callback
         @log_callback = proc do |level, msg|
-          @logger.send(level, msg)
+          @logger.public_send(level, msg)
         end
 
         Binding.setopt_log_handler(@mongocrypt, @log_callback)
diff --git a/lib/mongo/cursor.rb b/lib/mongo/cursor.rb
index 7d86d8665e..d9181b4422 100644
--- a/lib/mongo/cursor.rb
+++ b/lib/mongo/cursor.rb
@@ -507,7 +507,7 @@ def use_limit?
     end
 
     def limit
-      @view.send(:limit)
+      @view.limit
     end
 
     def register
diff --git a/lib/mongo/options/redacted.rb b/lib/mongo/options/redacted.rb
index 767a1f037f..d18c67c45f 100644
--- a/lib/mongo/options/redacted.rb
+++ b/lib/mongo/options/redacted.rb
@@ -143,14 +143,14 @@ def select!
 
       def redacted_string(method)
         '{' + reduce([]) do |list, (k, v)|
-          list << "#{k.send(method)}=>#{redact(k, v, method)}"
+          list << "#{k.public_send(method)}=>#{redact(k, v, method)}"
         end.join(', ') + '}'
       end
 
       def redact(k, v, method)
         return STRING_REPLACEMENT if SENSITIVE_OPTIONS.include?(k.to_sym)
 
-        v.send(method)
+        v.public_send(method)
       end
     end
   end
diff --git a/lib/mongo/socket/ssl.rb b/lib/mongo/socket/ssl.rb
index ef8c8f77a8..3c02c130a8 100644
--- a/lib/mongo/socket/ssl.rb
+++ b/lib/mongo/socket/ssl.rb
@@ -421,13 +421,13 @@ def load_private_key(text, passphrase)
         # https://github.com/jruby/jruby-openssl/issues/176
         if BSON::Environment.jruby?
           [ OpenSSL::PKey::RSA, OpenSSL::PKey::DSA ].each do |cls|
-            return cls.send(:new, *args)
+            return cls.new(*args)
           rescue OpenSSL::PKey::PKeyError
             # ignore
           end
           # Neither RSA nor DSA worked, fall through to trying PKey
         end
-        OpenSSL::PKey.send(:read, *args)
+        OpenSSL::PKey.read(*args)
       end
 
       def set_cert_verification(context, options)

From 51ecb94ff37700a76c872eb99af8277ee9f62ca5 Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 14:17:36 -0600
Subject: [PATCH 03/10] RUBY-3816 Use Monitor#running? instead of reaching into
 @thread

server_selection_diagnostic_message reached into each server monitor's
private @thread ivar to decide whether the monitor was dead. BackgroundThread
already exposes a public #running? predicate with exactly the needed
semantics (nil thread or dead thread => not running), so use it.

Guard with safe navigation: server.monitor can be nil, and the old
instance_variable_get(:@thread) silently returned nil for that case
(counting the monitor as dead), which &.running? preserves.
---
 lib/mongo/server_selector/base.rb | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/mongo/server_selector/base.rb b/lib/mongo/server_selector/base.rb
index bbab09cadf..858bbb418f 100644
--- a/lib/mongo/server_selector/base.rb
+++ b/lib/mongo/server_selector/base.rb
@@ -687,8 +687,7 @@ def server_selection_diagnostic_message(cluster)
         msg = ''
         dead_monitors = []
         cluster.servers_list.each do |server|
-          thread = server.monitor.instance_variable_get(:@thread)
-          dead_monitors << server if thread.nil? || !thread.alive?
+          dead_monitors << server unless server.monitor&.running?
         end
         if dead_monitors.any?
           msg += ". The following servers have dead monitor threads: #{dead_monitors.map(&:summary).join(', ')}"

From c20451dd651a85e90680b73f93e1eb90e1234813 Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 14:35:55 -0600
Subject: [PATCH 04/10] RUBY-3816 Call with_session and Index::View#limit
 without send

Client#with_session is already public, so three callers that invoked it
via send now call it directly. Collection::View#with_session was private
and reached via send from MapReduce; promote it to a public @api private
method and call it directly.

Also make Index::View#limit public (@api private). Cursor#limit calls
@view.limit, and @view may be an Index::View, so the method must be public
there as it already is on Collection::View. This removes the send that
Cursor previously needed and fixes the case exposed when Cursor#limit
stopped using send.
---
 lib/mongo/auth/user/view.rb             |  2 +-
 lib/mongo/collection.rb                 |  2 +-
 lib/mongo/collection/view.rb            | 12 ++++++++----
 lib/mongo/collection/view/map_reduce.rb |  2 +-
 lib/mongo/index/view.rb                 | 14 +++++++++-----
 5 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/lib/mongo/auth/user/view.rb b/lib/mongo/auth/user/view.rb
index 31b174c4aa..0478851033 100644
--- a/lib/mongo/auth/user/view.rb
+++ b/lib/mongo/auth/user/view.rb
@@ -152,7 +152,7 @@ def generate(user, options)
         end
 
         def execute_operation(options)
-          client.send(:with_session, options) do |session|
+          client.with_session(options) do |session|
             op = yield session
             op.execute(next_primary(nil, session), context: Operation::Context.new(client: client, session: session))
           end
diff --git a/lib/mongo/collection.rb b/lib/mongo/collection.rb
index 0546abbfd8..3f4aaa2785 100644
--- a/lib/mongo/collection.rb
+++ b/lib/mongo/collection.rb
@@ -393,7 +393,7 @@ def create(opts = {})
       operation = { create: name }.merge(options)
       operation.delete(:write)
       operation.delete(:write_concern)
-      client.send(:with_session, opts) do |session|
+      client.with_session(opts) do |session|
         write_concern = if opts[:write_concern]
                           WriteConcern.get(opts[:write_concern])
                         else
diff --git a/lib/mongo/collection/view.rb b/lib/mongo/collection/view.rb
index fb894ab9d8..fbb217b9b0 100644
--- a/lib/mongo/collection/view.rb
+++ b/lib/mongo/collection/view.rb
@@ -236,6 +236,14 @@ def operation_timeouts(opts = {})
         end
       end
 
+      # Executes the provided block within the context of a session, using
+      # this view's options merged with the given ones.
+      #
+      # @api private
+      def with_session(opts = {}, &block)
+        client.with_session(@options.merge(opts), &block)
+      end
+
       private
 
       def initialize_copy(other)
@@ -252,10 +260,6 @@ def new(options)
       def view
         self
       end
-
-      def with_session(opts = {}, &block)
-        client.with_session(@options.merge(opts), &block)
-      end
     end
   end
 end
diff --git a/lib/mongo/collection/view/map_reduce.rb b/lib/mongo/collection/view/map_reduce.rb
index 843f4d6575..163bce12df 100644
--- a/lib/mongo/collection/view/map_reduce.rb
+++ b/lib/mongo/collection/view/map_reduce.rb
@@ -227,7 +227,7 @@ def verbose(value = nil)
         #
         # @since 2.5.0
         def execute
-          view.send(:with_session, @options) do |session|
+          view.with_session(@options) do |session|
             write_concern = view.write_concern_with_session(session)
             context = Operation::Context.new(client: client, session: session)
             nro_write_with_retry(write_concern, context: context) do |connection, _txn_num, context|
diff --git a/lib/mongo/index/view.rb b/lib/mongo/index/view.rb
index 84d332fc1b..6e7cf88264 100644
--- a/lib/mongo/index/view.rb
+++ b/lib/mongo/index/view.rb
@@ -347,12 +347,20 @@ def operation_timeouts(opts = {})
         end
       end
 
+      # The query limit for an index view. Always -1; present so a Cursor
+      # can treat an index view like a collection view.
+      #
+      # @api private
+      def limit
+        -1
+      end
+
       private
 
       def drop_by_name(name, opts = {})
         session_options = @options.dup
         session_options[:session] = opts[:session] if opts[:session]
-        client.send(:with_session, session_options) do |session|
+        client.with_session(session_options) do |session|
           spec = {
             db_name: database.name,
             coll_name: collection.name,
@@ -396,10 +404,6 @@ def initial_query_op(session)
         Operation::Indexes.new(indexes_spec(session))
       end
 
-      def limit
-        -1
-      end
-
       def normalize_keys(spec)
         return false if spec.is_a?(String)
 

From 07afd1fd55ea94f7d752d8ba37b6b424e7e637b0 Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 14:42:37 -0600
Subject: [PATCH 05/10] RUBY-3816 Expose internal Session and Client methods
 instead of send

Session#txn_read_concern and Session#causal_consistency_doc were private
and reached via send from operation and view code; make them public
@api private and call them directly.

Client#monitoring was public but then re-marked private, and reached via
send from the auto encrypter; drop the private marker (it is already
documented @api private) and call it directly.
---
 lib/mongo/client.rb                           |  1 -
 lib/mongo/collection/view/readable.rb         |  2 +-
 lib/mongo/crypt/auto_encrypter.rb             |  2 +-
 .../operation/shared/sessions_supported.rb    |  2 +-
 lib/mongo/session.rb                          | 23 +++++++++++--------
 5 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/lib/mongo/client.rb b/lib/mongo/client.rb
index ed857402aa..66fe0e49bc 100644
--- a/lib/mongo/client.rb
+++ b/lib/mongo/client.rb
@@ -172,7 +172,6 @@ def monitoring
         @monitoring
       end
     end
-    private :monitoring
 
     # Determine if this client is equivalent to another object.
     #
diff --git a/lib/mongo/collection/view/readable.rb b/lib/mongo/collection/view/readable.rb
index 01109dfff5..5c30e503bd 100644
--- a/lib/mongo/collection/view/readable.rb
+++ b/lib/mongo/collection/view/readable.rb
@@ -678,7 +678,7 @@ def timeout_ms(timeout_ms = nil)
         # @api private
         def read_concern
           if options[:session] && options[:session].in_transaction?
-            options[:session].send(:txn_read_concern) || collection.client.read_concern
+            options[:session].txn_read_concern || collection.client.read_concern
           else
             collection.read_concern
           end
diff --git a/lib/mongo/crypt/auto_encrypter.rb b/lib/mongo/crypt/auto_encrypter.rb
index 35d72cb6dc..5f3673f892 100644
--- a/lib/mongo/crypt/auto_encrypter.rb
+++ b/lib/mongo/crypt/auto_encrypter.rb
@@ -287,7 +287,7 @@ def internal_client(client)
         @internal_client ||= client.with(
           auto_encryption_options: nil,
           min_pool_size: 0,
-          monitoring: client.send(:monitoring)
+          monitoring: client.monitoring
         )
       end
     end
diff --git a/lib/mongo/operation/shared/sessions_supported.rb b/lib/mongo/operation/shared/sessions_supported.rb
index eb2d50d53a..9b461ce969 100644
--- a/lib/mongo/operation/shared/sessions_supported.rb
+++ b/lib/mongo/operation/shared/sessions_supported.rb
@@ -61,7 +61,7 @@ def apply_causal_consistency!(selector, connection)
       def apply_causal_consistency_if_possible(selector, connection)
         return if connection.description.standalone?
 
-        cc_doc = session.send(:causal_consistency_doc)
+        cc_doc = session.causal_consistency_doc
         return unless cc_doc
 
         rc_doc = (selector[:readConcern] || read_concern || {}).merge(cc_doc)
diff --git a/lib/mongo/session.rb b/lib/mongo/session.rb
index e266b57a97..7fa906f074 100644
--- a/lib/mongo/session.rb
+++ b/lib/mongo/session.rb
@@ -1312,8 +1312,6 @@ def inside_with_transaction?
       @inside_with_transaction
     end
 
-    private
-
     # Get the read concern the session will use when starting a transaction.
     #
     # This is a driver style hash with underscore keys.
@@ -1324,11 +1322,24 @@ def inside_with_transaction?
     # @return [ Hash ] The read concern used for starting transactions.
     #
     # @since 2.9.0
+    # @api private
     def txn_read_concern
       # Read concern is inherited from client but not db or collection.
       txn_options[:read_concern] || @client.read_concern
     end
 
+    # Returns causal consistency document if the last operation time is
+    # known and causal consistency is enabled, otherwise returns nil.
+    #
+    # @api private
+    def causal_consistency_doc
+      return unless operation_time && causal_consistency?
+
+      { afterClusterTime: operation_time }
+    end
+
+    private
+
     def within_states?(*states)
       states.include?(@state)
     end
@@ -1346,14 +1357,6 @@ def txn_write_concern
         (@client.write_concern && @client.write_concern.options)
     end
 
-    # Returns causal consistency document if the last operation time is
-    # known and causal consistency is enabled, otherwise returns nil.
-    def causal_consistency_doc
-      return unless operation_time && causal_consistency?
-
-      { afterClusterTime: operation_time }
-    end
-
     def causal_consistency?
       @causal_consistency ||= if @options.key?(:causal_consistency)
                                 !!@options[:causal_consistency]

From dca02bfb4158d6678fce3a917827fecbd0cf1e3e Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 14:44:48 -0600
Subject: [PATCH 06/10] RUBY-3816 Expose view server_selector and
 FSBucket#ensure_indexes!

Collection::View#server_selector (from Readable) was private and reached
via send from MapReduce and Aggregation, whose @view is a Collection::View.
Make it public @api private and call it directly.

FSBucket#ensure_indexes! was private and reached via send from the write
stream. Make it public @api private and call it directly.
---
 .../collection/view/aggregation/behavior.rb   |  2 +-
 lib/mongo/collection/view/map_reduce.rb       |  2 +-
 lib/mongo/collection/view/readable.rb         | 16 ++++---
 lib/mongo/grid/fs_bucket.rb                   | 46 +++++++++++--------
 lib/mongo/grid/stream/write.rb                |  2 +-
 5 files changed, 39 insertions(+), 29 deletions(-)

diff --git a/lib/mongo/collection/view/aggregation/behavior.rb b/lib/mongo/collection/view/aggregation/behavior.rb
index db881106a7..43fbdef416 100644
--- a/lib/mongo/collection/view/aggregation/behavior.rb
+++ b/lib/mongo/collection/view/aggregation/behavior.rb
@@ -85,7 +85,7 @@ def perform_setup(view, options, forbid: [])
           end
 
           def server_selector
-            @view.send(:server_selector)
+            @view.server_selector
           end
 
           def aggregate_spec(session, read_preference = nil)
diff --git a/lib/mongo/collection/view/map_reduce.rb b/lib/mongo/collection/view/map_reduce.rb
index 163bce12df..b55cb7d80e 100644
--- a/lib/mongo/collection/view/map_reduce.rb
+++ b/lib/mongo/collection/view/map_reduce.rb
@@ -241,7 +241,7 @@ def execute
         OUT_ACTIONS = %i[replace merge reduce].freeze
 
         def server_selector
-          @view.send(:server_selector)
+          @view.server_selector
         end
 
         def inline?
diff --git a/lib/mongo/collection/view/readable.rb b/lib/mongo/collection/view/readable.rb
index 5c30e503bd..145f533639 100644
--- a/lib/mongo/collection/view/readable.rb
+++ b/lib/mongo/collection/view/readable.rb
@@ -749,12 +749,10 @@ def parallel_scan(cursor_count, options = {})
           end
         end
 
-        private
-
-        def collation(doc = nil)
-          configure(:collation, doc)
-        end
-
+        # The server selector for this view, derived from its read
+        # preference (or the collection/client default).
+        #
+        # @api private
         def server_selector
           @server_selector ||= if options[:session] && options[:session].in_transaction?
                                  ServerSelector.get(read_preference || client.server_selector)
@@ -763,6 +761,12 @@ def server_selector
                                end
         end
 
+        private
+
+        def collation(doc = nil)
+          configure(:collation, doc)
+        end
+
         def validate_doc!(doc)
           raise Error::InvalidDocument.new unless doc.respond_to?(:keys)
         end
diff --git a/lib/mongo/grid/fs_bucket.rb b/lib/mongo/grid/fs_bucket.rb
index 64180e9033..dae94c3dbb 100644
--- a/lib/mongo/grid/fs_bucket.rb
+++ b/lib/mongo/grid/fs_bucket.rb
@@ -494,6 +494,32 @@ def drop(opts = {})
         chunks_collection.drop(timeout_ms: context.remaining_timeout_ms)
       end
 
+      # Ensures the files and chunks collections have their required indexes,
+      # creating any that are missing.
+      #
+      # @param [ CsotTimeoutHolder | nil ] timeout_holder The timeout holder.
+      #
+      # @api private
+      def ensure_indexes!(timeout_holder = nil)
+        fc_idx = files_collection.find(
+          {},
+          limit: 1,
+          projection: { _id: 1 },
+          timeout_ms: timeout_holder&.remaining_timeout_ms
+        ).first
+        create_index_if_missing!(files_collection, FSBucket::FILES_INDEX) if fc_idx.nil?
+
+        cc_idx = chunks_collection.find(
+          {},
+          limit: 1,
+          projection: { _id: 1 },
+          timeout_ms: timeout_holder&.remaining_timeout_ms
+        ).first
+        return unless cc_idx.nil?
+
+        create_index_if_missing!(chunks_collection, FSBucket::CHUNKS_INDEX, unique: true)
+      end
+
       private
 
       # @param [ Hash ] opts The options.
@@ -516,26 +542,6 @@ def files_name
         "#{prefix}.#{Grid::File::Info::COLLECTION}"
       end
 
-      def ensure_indexes!(timeout_holder = nil)
-        fc_idx = files_collection.find(
-          {},
-          limit: 1,
-          projection: { _id: 1 },
-          timeout_ms: timeout_holder&.remaining_timeout_ms
-        ).first
-        create_index_if_missing!(files_collection, FSBucket::FILES_INDEX) if fc_idx.nil?
-
-        cc_idx = chunks_collection.find(
-          {},
-          limit: 1,
-          projection: { _id: 1 },
-          timeout_ms: timeout_holder&.remaining_timeout_ms
-        ).first
-        return unless cc_idx.nil?
-
-        create_index_if_missing!(chunks_collection, FSBucket::CHUNKS_INDEX, unique: true)
-      end
-
       def create_index_if_missing!(collection, index_spec, options = {})
         indexes_view = collection.indexes
         begin
diff --git a/lib/mongo/grid/stream/write.rb b/lib/mongo/grid/stream/write.rb
index 533ab911eb..a9b228b4ed 100644
--- a/lib/mongo/grid/stream/write.rb
+++ b/lib/mongo/grid/stream/write.rb
@@ -212,7 +212,7 @@ def file_info
           end
 
           def ensure_indexes!
-            fs.send(:ensure_indexes!, @timeout_holder)
+            fs.ensure_indexes!(@timeout_holder)
           end
 
           def ensure_open!

From 510089abd924501be8dc5e30d1d45000ec42668a Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 14:56:30 -0600
Subject: [PATCH 07/10] RUBY-3816 Expose message field helpers and connection
 socket interrupt

Message#fields and Message#serialize_fields were private and reached via
send during (de)serialization, including from Compressed. Make them public
@api private and call them directly; promote the Compressed#serialize_fields
override to match.

PushMonitor#stop! reached into its connection with send(:socket).close to
interrupt a blocking read. Add ConnectionCommon#interrupt_socket (@api
private) that encapsulates this, and call it instead.
---
 lib/mongo/protocol/compressed.rb      | 19 ++++++++++---------
 lib/mongo/protocol/message.rb         |  8 +++++---
 lib/mongo/server/connection_common.rb |  8 ++++++++
 lib/mongo/server/push_monitor.rb      |  2 +-
 4 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/lib/mongo/protocol/compressed.rb b/lib/mongo/protocol/compressed.rb
index 1aa221abaa..403553f629 100644
--- a/lib/mongo/protocol/compressed.rb
+++ b/lib/mongo/protocol/compressed.rb
@@ -93,7 +93,7 @@ def maybe_inflate
         message = Registry.get(@original_op_code).allocate
         buf = decompress(@compressed_message)
 
-        message.send(:fields).each do |field|
+        message.fields.each do |field|
           if field[:multi]
             message.deserialize_array(buf, field)
           else
@@ -116,6 +116,15 @@ def replyable?
         @original_message.replyable?
       end
 
+      # @api private
+      def serialize_fields(buffer, max_bson_size)
+        buf = BSON::ByteBuffer.new
+        @original_message.serialize_fields(buf, max_bson_size)
+        @uncompressed_size = buf.length
+        @compressed_message = compress(buf)
+        super
+      end
+
       private
 
       # The operation code for a +Compressed+ message.
@@ -140,14 +149,6 @@ def replyable?
       # @return [ String ] The actual compressed message bytes.
       field :compressed_message, Bytes
 
-      def serialize_fields(buffer, max_bson_size)
-        buf = BSON::ByteBuffer.new
-        @original_message.send(:serialize_fields, buf, max_bson_size)
-        @uncompressed_size = buf.length
-        @compressed_message = compress(buf)
-        super
-      end
-
       def compress(buffer)
         if @compressor_id == NOOP_BYTE
           buffer.to_s.force_encoding(BSON::BINARY)
diff --git a/lib/mongo/protocol/message.rb b/lib/mongo/protocol/message.rb
index a2d0938ece..08bff0e358 100644
--- a/lib/mongo/protocol/message.rb
+++ b/lib/mongo/protocol/message.rb
@@ -268,7 +268,7 @@ def self.deserialize(io,
         buf = BSON::ByteBuffer.new(chunk)
 
         message = Registry.get(_op_code).allocate
-        message.send(:fields).each do |field|
+        message.fields.each do |field|
           if field[:multi]
             message.deserialize_array(buf, field, options)
           else
@@ -403,11 +403,10 @@ def deserialize_field(io, field, options = {})
         )
       end
 
-      private
-
       # A method for getting the fields for a message class
       #
       # @return [Integer] the fields for the message class
+      # @api private
       def fields
         self.class.fields
       end
@@ -416,6 +415,7 @@ def fields
       #
       # @param buffer [String] buffer to receive the field
       # @return [String] buffer with serialized field
+      # @api private
       def serialize_fields(buffer, max_bson_size = nil)
         fields.each do |field|
           value = instance_variable_get(field[:name])
@@ -435,6 +435,8 @@ def serialize_fields(buffer, max_bson_size = nil)
         end
       end
 
+      private
+
       # Serializes the header of the message consisting of 4 32bit integers
       #
       # The integers represent a message length placeholder (calculation of
diff --git a/lib/mongo/server/connection_common.rb b/lib/mongo/server/connection_common.rb
index 742e4f0522..f7bf2a1b8b 100644
--- a/lib/mongo/server/connection_common.rb
+++ b/lib/mongo/server/connection_common.rb
@@ -99,6 +99,14 @@ def handshake_command(handshake_document)
         end
       end
 
+      # Closes the underlying socket, if one is open, to interrupt an
+      # in-progress blocking read on the connection.
+      #
+      # @api private
+      def interrupt_socket
+        socket&.close
+      end
+
       private
 
       HELLO_DOC = BSON::Document.new({ hello: 1 }).freeze
diff --git a/lib/mongo/server/push_monitor.rb b/lib/mongo/server/push_monitor.rb
index 8013dac675..5f59204c4b 100644
--- a/lib/mongo/server/push_monitor.rb
+++ b/lib/mongo/server/push_monitor.rb
@@ -72,7 +72,7 @@ def stop!
             # Interrupt any in-progress exhausted hello reads by
             # disconnecting the connection.
             begin
-              @connection.send(:socket).close
+              @connection.interrupt_socket
             rescue StandardError
               nil
             end

From 582766798d463d698eee3ee23ba5a1fbe1af031f Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 15:08:25 -0600
Subject: [PATCH 08/10] Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 lib/mongo/protocol/message.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/mongo/protocol/message.rb b/lib/mongo/protocol/message.rb
index 08bff0e358..0b3c9f9b19 100644
--- a/lib/mongo/protocol/message.rb
+++ b/lib/mongo/protocol/message.rb
@@ -405,7 +405,7 @@ def deserialize_field(io, field, options = {})
 
       # A method for getting the fields for a message class
       #
-      # @return [Integer] the fields for the message class
+      # @return [Array<Hash>] The fields for the message class
       # @api private
       def fields
         self.class.fields

From d2b1a589409b32e28f9bbae224f2fd413db206a3 Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 15:44:05 -0600
Subject: [PATCH 09/10] make this `@api private` instead of `private`, so it
 can be invoked internally

---
 lib/mongo/database/cursor_command_view.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/mongo/database/cursor_command_view.rb b/lib/mongo/database/cursor_command_view.rb
index 3cbe2474a9..6489d7cd6b 100644
--- a/lib/mongo/database/cursor_command_view.rb
+++ b/lib/mongo/database/cursor_command_view.rb
@@ -84,9 +84,9 @@ def operation_timeouts(opts = {})
         database.operation_timeouts(opts)
       end
 
-      private
-
       # Cursors do not support a limit when built from a command response.
+      #
+      # @api private
       def limit
         nil
       end

From 85df05c91daa48d5616154427d9a53b8e1ac7984 Mon Sep 17 00:00:00 2001
From: Jamis Buck <jamis.buck@mongodb.com>
Date: Wed, 8 Jul 2026 16:33:19 -0600
Subject: [PATCH 10/10] bump drivers-evergreen-tools to fix npm installation
 failure

---
 .mod/drivers-evergreen-tools | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.mod/drivers-evergreen-tools b/.mod/drivers-evergreen-tools
index 9c21ebe36b..d8aa120a15 160000
--- a/.mod/drivers-evergreen-tools
+++ b/.mod/drivers-evergreen-tools
@@ -1 +1 @@
-Subproject commit 9c21ebe36bf099988360cb83288e4820aa3bf27c
+Subproject commit d8aa120a1590a68bfb337b98da1d240914a843c2