MONGOID-3381 MONGOID-3640 Remove support for server versions 3.6 and 4.0

.evergreen/config.yml

@@ -804,22 +804,6 @@ axes:
         variables:
           MONGODB_VERSION: "4.2"
           CRYPT_SHARED_VERSION: "6.0.5"
-      - id: "4.0"
-        display_name: "4.0"
-        variables:
-          MONGODB_VERSION: "4.0"
-      - id: "3.6"
-        display_name: "3.6"
-        variables:
-          MONGODB_VERSION: "3.6"
-
-  - id: fcv
-    display_name: FCV
-    values:
-      - id: '3.4'
-        display_name: '3.4'
-        variables:
-          FCV: '3.4'
 
   - id: "topology"
     display_name: Topology

.evergreen/config/axes.yml.erb

@@ -29,22 +29,6 @@ axes:
         variables:
           MONGODB_VERSION: "4.2"
           CRYPT_SHARED_VERSION: "6.0.5"
-      - id: "4.0"
-        display_name: "4.0"
-        variables:
-          MONGODB_VERSION: "4.0"
-      - id: "3.6"
-        display_name: "3.6"
-        variables:
-          MONGODB_VERSION: "3.6"
-
-  - id: fcv
-    display_name: FCV
-    values:
-      - id: '3.4'
-        display_name: '3.4'
-        variables:
-          FCV: '3.4'
 
   - id: "topology"
     display_name: Topology

lib/mongo/auth/conversation_base.rb

@@ -53,7 +53,7 @@ def speculative_auth_document
 
       # @return [ Protocol::Message ] The message to send.
       def build_message(connection, auth_source, selector)
-        if connection && connection.features.op_msg_enabled?
+        if connection
           selector = selector.dup
           selector[Protocol::Msg::DATABASE_IDENTIFIER] = auth_source
           cluster_time = connection.mongos? && connection.cluster_time

lib/mongo/auth/stringprep.rb

@@ -21,8 +21,7 @@
 module Mongo
   module Auth
     # This namespace contains all behavior related to string preparation
-    # (RFC 3454). It's used to implement SCRAM-SHA-256 authentication,
-    # which is available in MongoDB server versions 4.0 and later.
+    # (RFC 3454). It's used to implement SCRAM-SHA-256 authentication.
     #
     # @since 2.6.0
     # @api private

lib/mongo/bulk_write.rb

@@ -217,8 +217,6 @@ def base_spec(operation_id, session)
     end
 
     def execute_operation(name, values, connection, context, operation_id, result_combiner, session, txn_num = nil)
-      validate_collation!(connection)
-      validate_array_filters!(connection)
       validate_hint!(connection)
 
       unpin_maybe(session, connection) do
@@ -234,13 +232,9 @@ def execute_operation(name, values, connection, context, operation_id, result_co
           end
         end
       end
-    # With OP_MSG (3.6+ servers), the size of each section in the message
+    # The size of each section in the message
     # is independently capped at 16m and each bulk operation becomes
     # its own section. The size of the entire bulk write is limited to 48m.
-    # With OP_QUERY (pre-3.6 servers), the entire bulk write is sent as a
-    # single document and is thus subject to the 16m document size limit.
-    # This means the splits differ between pre-3.6 and 3.6+ servers, with
-    # 3.6+ servers being able to split less.
     rescue Error::MaxBSONSize, Error::MaxMessageSize => e
       raise e if values.size <= 1
       unpin_maybe(session, connection) do
@@ -297,33 +291,19 @@ def update_many(documents, connection, context, operation_id, session, txn_num)
 
     private
 
-    def validate_collation!(connection)
-      if op_combiner.has_collation? && !connection.features.collation_enabled?
-        raise Error::UnsupportedCollation.new
-      end
-    end
-
-    def validate_array_filters!(connection)
-      if op_combiner.has_array_filters? && !connection.features.array_filters_enabled?
-        raise Error::UnsupportedArrayFilters.new
-      end
-    end
-
     def validate_hint!(connection)
       if op_combiner.has_hint?
         if !can_hint?(connection) && write_concern && !write_concern.acknowledged?
           raise Error::UnsupportedOption.hint_error(unacknowledged_write: true)
-        elsif !connection.features.update_delete_option_validation_enabled?
-          raise Error::UnsupportedOption.hint_error
         end
       end
     end
 
     # Loop through the requests and check if each operation is allowed to send
     # a hint for each operation on the given server version.
     #
-    # For the following operations, the client can send a hint for servers >= 4.2
-    # and for the rest, the client can only send it for 4.4+:
+    # For the following operations, the client can send a hint for all supported
+    # server versions, and for the rest, the client can only send it for 4.4+:
     #   - updateOne
     #   - updateMany
     #   - replaceOne
@@ -333,13 +313,12 @@ def validate_hint!(connection)
     # @return [ true | false ] Whether the request is able to send hints for
     #   the current server version.
     def can_hint?(connection)
-      gte_4_2 = connection.server.description.server_version_gte?('4.2')
       gte_4_4 = connection.server.description.server_version_gte?('4.4')
       op_combiner.requests.all? do |req|
         op = req.keys.first
         if req[op].keys.include?(:hint)
           if [:update_one, :update_many, :replace_one].include?(op)
-            gte_4_2
+            true
           else
             gte_4_4
           end

lib/mongo/bulk_write/unordered_combiner.rb

@@ -24,8 +24,8 @@ class BulkWrite
     #
     # @since 2.1.0
     class UnorderedCombiner
-      include Transformable
       include Validatable
+      include Transformable
       include Combineable
 
       # Combine the requests in order.

lib/mongo/client.rb

@@ -230,8 +230,7 @@ def hash
     #   analogous options present in the URI string.
     #
     # @option options [ String, Symbol ] :app_name Application name that is
-    #   printed to the mongod logs upon establishing a connection in server
-    #   versions >= 3.4.
+    #   printed to the mongod logs upon establishing a connection
     # @option options [ Symbol ] :auth_mech The authentication mechanism to
     #   use. One of :mongodb_cr, :mongodb_x509, :plain, :scram, :scram256
     # @option options [ Hash ] :auth_mech_properties
@@ -308,7 +307,6 @@ def hash
     # @option options [ String ] :password The user's password.
     # @option options [ String ] :platform Platform information to include in
     #   the metadata printed to the mongod logs upon establishing a connection
-    #   in server versions >= 3.4.
     # @option options [ Hash ] :read The read preference options. The hash
     #   may have the following items:
     #   - *:mode* -- read preference specified as a symbol; valid values are
@@ -325,7 +323,7 @@ def hash
     #   reads are enabled (which is the default). If false, modern retryable
     #   reads are disabled and legacy retryable reads are enabled.
     # @option options [ true | false ] :retry_writes Retry writes once when
-    #   connected to a replica set or sharded cluster versions 3.6 and up.
+    #   connected to a replica set or sharded cluster.
     #   (Default is true.)
     # @option options [ true | false ] :scan Whether to scan all seeds
     #   in constructor. The default in driver version 2.x is to do so;
@@ -1045,9 +1043,8 @@ def start_session(options = {})
       end
     end
 
-    # As of version 3.6 of the MongoDB server, a ``$changeStream`` pipeline stage is supported
-    # in the aggregation framework. As of version 4.0, this stage allows users to request that
-    # notifications are sent for all changes that occur in the client's cluster.
+    # Allows users to request that notifications are sent for all changes that
+    # occur in the client's cluster.
     #
     # @example Get change notifications for the client's cluster.
     #  client.watch([{ '$match' => { operationType: { '$in' => ['insert', 'replace'] } } }])
@@ -1093,7 +1090,6 @@ def start_session(options = {})
     # @option options [ BSON::Timestamp ] :start_at_operation_time Only return
     #   changes that occurred at or after the specified timestamp. Any command run
     #   against the server will return a cluster time that can be used here.
-    #   Only recognized by server versions 4.0+.
     # @option options [ Object ] :comment A user-provided
     #   comment to attach to this command.
     # @option options [ Boolean ] :show_expanded_events Enables the server to

lib/mongo/collection.rb

@@ -576,10 +576,8 @@ def aggregate(pipeline, options = {})
       View.new(self, {}, options).aggregate(pipeline, options)
     end
 
-    # As of version 3.6 of the MongoDB server, a ``$changeStream`` pipeline
-    # stage is supported in the aggregation framework. This stage allows users
-    # to request that notifications are sent for all changes to a particular
-    # collection.
+    # Allows users to request that notifications are sent for all changes
+    # to a particular collection.
     #
     # @example Get change notifications for a given collection.
     #   collection.watch([{ '$match' => { operationType: { '$in' => ['insert', 'replace'] } } }])
@@ -627,7 +625,6 @@ def aggregate(pipeline, options = {})
     # @option options [ BSON::Timestamp ] :start_at_operation_time Only return
     #   changes that occurred at or after the specified timestamp. Any command run
     #   against the server will return a cluster time that can be used here.
-    #   Only recognized by server versions 4.0+.
     # @option options [ Object ] :comment A user-provided
     #   comment to attach to this command.
     # @option options [ Boolean ] :show_expanded_events Enables the server to
@@ -686,7 +683,7 @@ def watch(pipeline = [], options = {})
     #
     # @deprecated Use #count_documents or estimated_document_count instead. However, note that the
     #   following operators will need to be substituted when switching to #count_documents:
-    #     * $where should be replaced with $expr (only works on 3.6+)
+    #     * $where should be replaced with $expr
     #     * $near should be replaced with $geoWithin with $center
     #     * $nearSphere should be replaced with $geoWithin with $centerSphere
     def count(filter = nil, options = {})
@@ -706,7 +703,7 @@ def count(filter = nil, options = {})
     #
     # @option options :skip [ Integer ] The number of documents to skip.
     # @option options :hint [ Hash ] Override default index selection and force
-    #   MongoDB to use a specific index for the query. Requires server version 3.6+.
+    #   MongoDB to use a specific index for the query.
     # @option options :limit [ Integer ] Max number of docs to count.
     # @option options :max_time_ms [ Integer ] The maximum amount of time to allow the
     #   command to run.

lib/mongo/collection/view/change_stream.rb

@@ -27,14 +27,6 @@ class View
       # that notifications are sent for all changes to a particular collection
       # or database.
       #
-      # @note Only available in server versions 3.6 and higher.
-      # @note ChangeStreams do not work properly with JRuby because of the
-      #  issue documented here: https://github.com/jruby/jruby/issues/4212.
-      #  Namely, JRuby eagerly evaluates #next on an Enumerator in a background
-      #  green thread, therefore calling #next on the change stream will cause
-      #  getMores to be called in a loop in the background.
-      #
-      #
       # @since 2.5.0
       class ChangeStream
         include Aggregation::Behavior
@@ -114,7 +106,7 @@ class ChangeStream
         # @option options [ BSON::Timestamp ] :start_at_operation_time Only
         #   return changes that occurred at or after the specified timestamp. Any
         #   command run against the server will return a cluster time that can
-        #   be used here. Only recognized by server versions 4.0+.
+        #   be used here.
         # @option options [ Bson::Document, Hash ] :start_after Similar to :resume_after, this
         #   option takes a resume token and starts a new change stream returning the first
         #   notification after the token. This will allow users to watch collections that have been
@@ -340,18 +332,13 @@ def for_collection?
         def create_cursor!(timeout_ms = nil)
           # clear the cache because we may get a newer or an older server
           # (rolling upgrades)
-          @start_at_operation_time_supported = nil
-
           session = client.get_session(@options)
           context = Operation::Context.new(client: client, session: session, view: self, operation_timeouts: timeout_ms ? { operation_timeout_ms: timeout_ms } : operation_timeouts)
 
           start_at_operation_time = nil
-          start_at_operation_time_supported = nil
 
           @cursor = read_with_retry_cursor(session, server_selector, self, context: context) do |server|
             server.with_connection do |connection|
-              start_at_operation_time_supported = connection.description.server_version_gte?('4.0')
-
               result = send_initial_query(connection, context)
 
               if doc = result.replies.first && result.replies.first.documents.first
@@ -369,7 +356,6 @@ def create_cursor!(timeout_ms = nil)
           end
 
           @start_at_operation_time = start_at_operation_time
-          @start_at_operation_time_supported = start_at_operation_time_supported
         end
 
         def pipeline
@@ -405,12 +391,7 @@ def change_doc
                 # Spec says we need to remove both startAtOperationTime and startAfter if
                 # either was passed in by user, thus we won't forward them
                 doc[:resumeAfter] = resume_token
-              elsif @start_at_operation_time_supported && @start_at_operation_time
-                # It is crucial to check @start_at_operation_time_supported
-                # here - we may have switched to an older server that
-                # does not support operation times and therefore shouldn't
-                # try to send one to it!
-                #
+              elsif @start_at_operation_time
                 # @start_at_operation_time is already a BSON::Timestamp
                 doc[:startAtOperationTime] = @start_at_operation_time
               else

lib/mongo/collection/view/explainable.rb

@@ -44,12 +44,10 @@ module Explainable
         # @example Get the query plan for the query with execution statistics.
         #   view.explain(verbosity: :execution_stats)
         #
-        # @option opts [ true | false ] :verbose The level of detail
-        #   to return for MongoDB 2.6 servers.
         # @option opts [ String | Symbol ] :verbosity The type of information
-        #   to return for MongoDB 3.0 and newer servers. If the value is a
-        #   symbol, it will be stringified and converted from underscore
-        #   style to camel case style (e.g. :query_planner => "queryPlanner").
+        #   to return. If the value is a symbol, it will be stringified and
+        #   converted from underscore style to camel case style
+        #   (e.g. :query_planner => "queryPlanner").
         #
         # @return [ Hash ] A single document with the query plan.
         #
@@ -66,12 +64,10 @@ def explained?
           !!options[:explain]
         end
 
-        # @option opts [ true | false ] :verbose The level of detail
-        #   to return for MongoDB 2.6 servers.
         # @option opts [ String | Symbol ] :verbosity The type of information
-        #   to return for MongoDB 3.0 and newer servers. If the value is a
-        #   symbol, it will be stringified and converted from underscore
-        #   style to camel case style (e.g. :query_planner => "queryPlanner").
+        #   to return. If the value is a symbol, it will be stringified and
+        #   converted from underscore style to camel case style
+        #   (e.g. :query_planner => "queryPlanner").
         def explain_options(**opts)
           explain_limit = limit || 0
           # Note: opts will never be nil here.

lib/mongo/collection/view/iterable.rb

@@ -46,13 +46,14 @@ def each
 
           limit_for_cached_query = compute_limit_for_cached_query
 
-          # Ruby versions 2.5 and older do not support arr[0..nil] syntax, so
-          # this must be a separate conditional.
+          # TODO: rather than pulling the entire (limited) result set into
+          # memory, this should tell the cursor about the limit and then let
+          # the cursor limit the iteration as necessary.
           cursor_to_iterate = if limit_for_cached_query
-            @cursor.to_a[0...limit_for_cached_query]
-          else
-            @cursor
-          end
+                                @cursor.to_a[0...limit_for_cached_query]
+                              else
+                                @cursor
+                              end
 
           cursor_to_iterate.each do |doc|
             yield doc

lib/mongo/collection/view/map_reduce.rb

@@ -39,7 +39,7 @@ class MapReduce
         #
         # @since 2.1.0
         # @deprecated
-        REROUTE = 'Rerouting the MapReduce operation to the primary server.'.freeze
+        REROUTE = 'Rerouting the MapReduce operation to the primary server'.freeze
 
         # @return [ View ] view The collection view.
         attr_reader :view
@@ -124,7 +124,7 @@ def initialize(view, map, reduce, options = {})
           @reduce_function = reduce.dup.freeze
           @options = BSON::Document.new(options).freeze
 
-          client.log_warn('The map_reduce operation is deprecated, please use the aggregation pipeline instead')
+          Deprecations.warn(:map_reduce, 'The map_reduce operation is deprecated, please use the aggregation pipeline instead.')
         end
 
         # Set or get the jsMode flag for the operation.
@@ -298,7 +298,7 @@ def send_initial_query_with_connection(connection, session, context:)
           if valid_server?(connection.description)
             op.execute_with_connection(connection, context: context)
           else
-            msg = "Rerouting the MapReduce operation to the primary server - #{connection.address} is not suitable because it is not currently the primray"
+            msg = "#{REROUTE} - #{connection.address} is not suitable because it is not currently the primary"
             log_warn(msg)
             server = cluster.next_primary(nil, session)
             op.execute(server, context: context)