RUBY-3816 Remove core driver antipatterns (#3078)

* 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.

* 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.

* 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.

* 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.

* 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.

* 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.

* 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.

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* make this `@api private` instead of `private`, so it can be invoked internally

* bump drivers-evergreen-tools to fix npm installation failure

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: jamis

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

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

lib/mongo/client.rb

@@ -172,7 +172,6 @@ def monitoring
         @monitoring
       end
     end
-    private :monitoring
 
     # Determine if this client is equivalent to another object.
     #
@@ -796,10 +795,10 @@ 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 +854,31 @@ 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.

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
 

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)

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

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

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)

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|
@@ -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?

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
@@ -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