1 files changed, 47 insertions, 12 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index fa10f18cb7..f7d75e6748 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -76,7 +76,7 @@ module ActiveRecord
 
       SIMPLE_INT = /\A\d+\z/
 
-      attr_accessor :visitor, :pool
+      attr_accessor :visitor, :pool, :prevent_writes
       attr_reader :schema_cache, :owner, :logger, :prepared_statements, :lock
       alias :in_use? :owner
 
@@ -100,6 +100,11 @@ module ActiveRecord
         end
       end
 
+      def self.build_read_query_regexp(*parts) # :nodoc:
+        parts = parts.map { |part| /\A\s*#{part}/i }
+        Regexp.union(*parts)
+      end
+
       def initialize(connection, logger = nil, config = {}) # :nodoc:
         super()
 
@@ -125,12 +130,35 @@ module ActiveRecord
         @advisory_locks_enabled = self.class.type_cast_config_to_boolean(
           config.fetch(:advisory_locks, true)
         )
+
+        check_version
       end
 
       def replica?
         @config[:replica] || false
       end
 
+      # Determines whether writes are currently being prevents.
+      #
+      # Returns true if the connection is a replica, or if +prevent_writes+
+      # is set to true.
+      def preventing_writes?
+        replica? || prevent_writes
+      end
+
+      # Prevent writing to the database  regardless of role.
+      #
+      # In some cases you may want to prevent writes to the database
+      # even if you are on a database that can write. `while_preventing_writes`
+      # will prevent writes to the database for the duration of the block.
+      def while_preventing_writes
+        original = self.prevent_writes
+        self.prevent_writes = true
+        yield
+      ensure
+        self.prevent_writes = original
+      end
+
       def migrations_paths # :nodoc:
         @config[:migrations_paths] || Migrator.migrations_paths
       end
@@ -312,6 +340,11 @@ module ActiveRecord
         false
       end
 
+      # Does this adapter support materialized views?
+      def supports_materialized_views?
+        false
+      end
+
       # Does this adapter support datetime with precision?
       def supports_datetime_with_precision?
         false
@@ -502,6 +535,9 @@ module ActiveRecord
       end
 
       private
+        def check_version
+        end
+
         def type_map
           @type_map ||= Type::TypeMap.new.tap do |mapping|
             initialize_type_map(mapping)
@@ -575,14 +611,12 @@ module ActiveRecord
           $1.to_i if sql_type =~ /\((.*)\)/
         end
 
-        def translate_exception_class(e, sql)
-          begin
-            message = "#{e.class.name}: #{e.message}: #{sql}"
-          rescue Encoding::CompatibilityError
-            message = "#{e.class.name}: #{e.message.force_encoding sql.encoding}: #{sql}"
-          end
+        def translate_exception_class(e, sql, binds)
+          message = "#{e.class.name}: #{e.message}"
 
-          exception = translate_exception(e, message)
+          exception = translate_exception(
+            e, message: message, sql: sql, binds: binds
+          )
           exception.set_backtrace e.backtrace
           exception
         end
@@ -595,24 +629,25 @@ module ActiveRecord
             binds:             binds,
             type_casted_binds: type_casted_binds,
             statement_name:    statement_name,
-            connection_id:     object_id) do
+            connection_id:     object_id,
+            connection:        self) do
             begin
               @lock.synchronize do
                 yield
               end
             rescue => e
-              raise translate_exception_class(e, sql)
+              raise translate_exception_class(e, sql, binds)
             end
           end
         end
 
-        def translate_exception(exception, message)
+        def translate_exception(exception, message:, sql:, binds:)
           # override in derived class
           case exception
           when RuntimeError
             exception
           else
-            ActiveRecord::StatementInvalid.new(message)
+            ActiveRecord::StatementInvalid.new(message, sql: sql, binds: binds)
           end
         end