`Postgres::OID::Range` serializes to a `Range`, quote in `Quoting`

PostgreSQL 9.1+ introduced range types, and Rails added support for
using this datatype in ActiveRecord. However, the serialization of
`PostgreSQL::OID::Range` was incomplete, because it did not properly
quote the bounds that make up the range. A clear example of this is a
`tsrange`.

Normally, ActiveRecord quotes Date/Time objects to include the
milliseconds. However, the way `PostgreSQL::OID::Range` serialized its
bounds, the milliseconds were dropped. This meant that the value was
incomplete and not equal to the submitted value.

An example of normal timestamps vs. a `tsrange`. Note how the bounds
for the range do not include their milliseconds (they were present in
the ruby Range):

    UPDATE "iterations" SET "updated_at" = $1, "range" = $2 WHERE
    "iterations"."id" = $3
    [["updated_at", "2017-09-23 17:07:01.304864"],
    ["range", "[2017-09-23 00:00:00 UTC,2017-09-23 23:59:59 UTC]"],
    ["id", 1234]]

`PostgreSQL::OID::Range` serialized the range by interpolating a
string for the range, which works for most cases, but does not work
for timestamps:

    def serialize(value)
      if value.is_a?(::Range)
        from = type_cast_single_for_database(value.begin)
        to = type_cast_single_for_database(value.end)
        "[#{from},#{to}#{value.exclude_end? ? ')' : ']'}"
      else
        super
      end
    end

    (byebug) from = type_cast_single_for_database(value.begin)
    2010-01-01 13:30:00 UTC

    (byebug) to = type_cast_single_for_database(value.end)
    2011-02-02 19:30:00 UTC

    (byebug) "[#{from},#{to}#{value.exclude_end? ? ')' : ']'}"
    "[2010-01-01 13:30:00 UTC,2011-02-02 19:30:00 UTC)"

@sgrif (the original implementer for Postgres Range support) provided
some feedback about where the quoting should occur:

  Yeah, quoting at all is definitely wrong here. I'm not sure what I
  was thinking in 02579b5, but what this is doing is definitely in the
  wrong place. It should probably just be returning a range of
  subtype.serialize(value.begin) and subtype.serialize(value.end), and
  letting the adapter handle the rest.

`Postgres::OID::Range` now returns a `Range` object, and
`ActiveRecord::ConnectionAdapters::PostgreSQL::Quoting` can now encode
and quote a `Range`:

    def encode_range(range)
      "[#{type_cast(range.first)},#{type_cast(range.last)}#{range.exclude_end? ? ')' : ']'}"
    end

    ...

    encode_range(range)
    #=> "['2010-01-01 13:30:00.670277','2011-02-02 19:30:00.745125')"

This commit includes tests to make sure the milliseconds are
preserved in `tsrange` and `tstzrange` columns

1 files changed, 1 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
index 7d5d7d91e6..a89aa5ea09 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
@@ -35,7 +35,7 @@ module ActiveRecord
             if value.is_a?(::Range)
               from = type_cast_single_for_database(value.begin)
               to = type_cast_single_for_database(value.end)
-              "[#{from},#{to}#{value.exclude_end? ? ')' : ']'}"
+              ::Range.new(from, to, value.exclude_end?)
             else
               super
             end