Fix RUBY-1385 and RUBY-1386 (#983)

* Fix RUBY-1385 and RUBY-1386

* Tests

* Fix tests

* Fix usage

Author: p-mongo

lib/mongo.rb

@@ -42,3 +42,4 @@
 require 'mongo/uri'
 require 'mongo/version'
 require 'mongo/write_concern'
+require 'mongo/lint'

lib/mongo/client.rb

@@ -261,6 +261,7 @@ def hash
     #
     # @since 2.0.0
     def initialize(addresses_or_uri, options = Options::Redacted.new)
+      Mongo::Lint.validate_underscore_read_preference(options[:read])
       if addresses_or_uri.is_a?(::String)
         create_from_uri(addresses_or_uri, validate_options!(options))
       else

lib/mongo/collection/view/builder/op_query.rb

@@ -68,7 +68,15 @@ def requires_special_filter?
           end
 
           def read_pref_formatted
-            @read_formatted ||= ServerSelector.get(read).to_mongos if read
+            @read_formatted ||= begin
+              if read
+                read_pref = ServerSelector.get(read).to_mongos
+                Mongo::Lint.validate_camel_case_read_preference(read_pref)
+                read_pref
+              else
+                nil
+              end
+            end
           end
 
           def special_filter

lib/mongo/collection/view/readable.rb

@@ -139,6 +139,7 @@ def count(opts = {})
           cmd[:limit] = opts[:limit] if opts[:limit]
           cmd[:maxTimeMS] = opts[:max_time_ms] if opts[:max_time_ms]
           cmd[:readConcern] = collection.read_concern if collection.read_concern
+          Mongo::Lint.validate_underscore_read_preference(opts[:read])
           read_pref = opts[:read] || read_preference
           selector = ServerSelector.get(read_pref || server_selector)
           with_session(opts) do |session|
@@ -203,6 +204,7 @@ def estimated_document_count(opts = {})
           cmd = { count: collection.name }
           cmd[:maxTimeMS] = opts[:max_time_ms] if opts[:max_time_ms]
           cmd[:readConcern] = collection.read_concern if collection.read_concern
+          Mongo::Lint.validate_underscore_read_preference(opts[:read])
           read_pref = opts[:read] || read_preference
           selector = ServerSelector.get(read_pref || server_selector)
           with_session(opts) do |session|
@@ -240,6 +242,7 @@ def distinct(field_name, opts = {})
                   :query => filter }
           cmd[:maxTimeMS] = opts[:max_time_ms] if opts[:max_time_ms]
           cmd[:readConcern] = collection.read_concern if collection.read_concern
+          Mongo::Lint.validate_underscore_read_preference(opts[:read])
           read_pref = opts[:read] || read_preference
           selector = ServerSelector.get(read_pref || server_selector)
           with_session(opts) do |session|
@@ -537,11 +540,13 @@ def collation(doc = nil)
         end
 
         def read_preference
-          if options[:session] && options[:session].in_transaction?
-            options[:session].send(:txn_read_pref) || collection.client.read_preference
+          rp = if options[:session] && options[:session].in_transaction?
+            options[:session].txn_read_preference || collection.client.read_preference
           else
             @read_preference ||= (options[:read] || collection.read_preference)
           end
+          Mongo::Lint.validate_underscore_read_preference(rp)
+          rp
         end
 
         def server_selector

lib/mongo/database.rb

@@ -153,7 +153,8 @@ def collections
     #
     # @return [ Hash ] The result of the command execution.
     def command(operation, opts = {})
-      txn_read_pref = opts[:session] && opts[:session].in_transaction? && opts[:session].txn_read_pref
+      txn_read_pref = opts[:session] && opts[:session].in_transaction? && opts[:session].txn_read_preference
+      Mongo::Lint.validate_underscore_read_preference(txn_read_pref)
       preference = ServerSelector.get(txn_read_pref || opts[:read] || ServerSelector::PRIMARY)
       server = preference.select_server(cluster)
 

lib/mongo/error.rb

@@ -151,6 +151,7 @@ def add_label(label)
 require 'mongo/error/invalid_uri'
 require 'mongo/error/invalid_write_concern'
 require 'mongo/error/insufficient_iteration_count'
+require 'mongo/error/lint_error'
 require 'mongo/error/max_bson_size'
 require 'mongo/error/max_message_size'
 require 'mongo/error/mismatched_domain'

lib/mongo/error/lint_error.rb

@@ -0,0 +1,35 @@
+# Copyright (C) 2018 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
+
+    # Raised when the driver is used incorrectly.
+    #
+    # Normally the driver passes certain data to the server and lets the
+    # server return an error if the data is invalid. This makes it possible
+    # for the server to add functionality in the future and for older
+    # driver versions to support such functionality transparently, but
+    # also complicates debugging.
+    #
+    # Setting the environment variable MONGO_RUBY_DRIVER_LINT to 1, true
+    # or yes will make the driver perform additional checks on data it passes
+    # to the server, to flag failures sooner. This exception is raised on
+    # such failures.
+    #
+    # @since 2.7.0
+    class LintError < Error
+    end
+  end
+end

lib/mongo/lint.rb

@@ -0,0 +1,45 @@
+module Mongo
+  # @api private
+  module Lint
+    def validate_underscore_read_preference(read_pref)
+      return unless enabled?
+      if read_pref
+        validate_underscore_read_preference_mode(read_pref[:mode] || read_pref['mode'])
+      end
+    end
+    module_function :validate_underscore_read_preference
+
+    def validate_underscore_read_preference_mode(mode)
+      return unless enabled?
+      if mode
+        unless %w(primary primary_preferred secondary secondary_preferred nearest).include?(mode.to_s)
+          raise Error::LintError, "Invalid read preference mode: #{mode}"
+        end
+      end
+    end
+    module_function :validate_underscore_read_preference_mode
+
+    def validate_camel_case_read_preference(read_pref)
+      return unless enabled?
+      if read_pref
+        validate_camel_case_read_preference_mode(read_pref[:mode] || read_pref['mode'])
+      end
+    end
+    module_function :validate_camel_case_read_preference
+
+    def validate_camel_case_read_preference_mode(mode)
+      return unless enabled?
+      if mode
+        unless %w(primary primaryPreferred secondary secondaryPreferred nearest).include?(mode.to_s)
+          raise Error::LintError, "Invalid read preference mode: #{mode}"
+        end
+      end
+    end
+    module_function :validate_camel_case_read_preference_mode
+
+    def enabled?
+      ENV['MONGO_RUBY_DRIVER_LINT'] && %w(1 yes true).include?(ENV['MONGO_RUBY_DRIVER_LINT'].downcase)
+    end
+    module_function :enabled?
+  end
+end

lib/mongo/operation/shared/read_preference_supported.rb

@@ -30,8 +30,9 @@ def options(server)
 
       def update_selector_for_read_pref(sel, server)
         if read && server.mongos? && read_pref = read.to_mongos
+          Mongo::Lint.validate_camel_case_read_preference(read_pref)
           sel = sel[:$query] ? sel : {:$query => sel}
-          sel.merge(:$readPreference => read_pref)
+          sel = sel.merge(:$readPreference => read_pref)
         else
           sel
         end

lib/mongo/operation/shared/sessions_supported.rb

@@ -99,8 +99,8 @@ def suppress_read_write_concern!(selector)
         session.suppress_read_write_concern!(selector)
       end
 
-      def validate_read_pref!(selector)
-        session.validate_read_pref!(selector) if read_command?(selector)
+      def validate_read_preference!(selector)
+        session.validate_read_preference!(selector) if read_command?(selector)
       end
 
       def update_session_state!
@@ -123,7 +123,7 @@ def command(server)
             apply_autocommit!(sel)
             apply_txn_opts!(sel)
             suppress_read_write_concern!(sel)
-            validate_read_pref!(sel)
+            validate_read_preference!(sel)
             update_session_state!
             apply_txn_num!(sel)
           end
@@ -136,7 +136,7 @@ def command(server)
           apply_autocommit!(sel)
           apply_txn_opts!(sel)
           suppress_read_write_concern!(sel)
-          validate_read_pref!(sel)
+          validate_read_preference!(sel)
           update_session_state!
           apply_txn_num!(sel)
         end