Add sort_ranges parameter and range_combine_end method for PostgreSQL 14 compatibility

[Danieth]

1. Adding range_combine_end method

PostgreSQL 14 handles overlaps slightly differently than the current implementation.

PG Multirange Column	Ruby Class	Overlap between inclusive end Ranges?
int4multirange	Integer	end + 1 >= begin
int8multirange	Integer	end + 1 >= begin
nummultirange	Float	end >= begin
datemultirange	Date	end + '1 day' >= begin
tsmultirange	Time	end >= begin
tstzmultirange	ActiveSupport::TimeWithZone	end >= begin

The existing logic to handle overlaps works perfectly for Integers, Floats & Dates. This logic, however, does not work for Time or ActiveSupport::TimeWithZone.

The current logic (+ 1) adds 1 day to Time, ActiveSupport::TimeWithZone - when merge overlaps is called, this can lead to ranges being merged that wouldn't be merged in PostgreSQL.

PostgreSQL truncates timestamps to microseconds and then merges ranges that overlap - I duplicated this logic by adding nanoseconds to handle rounding the end temporarily and then checking if the end is greater or equal to the beginning of the next range.

PostgreSQL is the only Database to have Multiranges - so I believe it is ok for this library duplicate the logic present there.

2. Adding sort_ranges parameter to initializer

When working with an already sorted multirange (like when pulling PostgreSQL Multiranges directly from the database), it's going to be a lot faster to have the MultiRange skip sorting the ranges.

I believe this parameter could also be used internally to make the data structure faster in some cases (When creating new ranges during difference & intersection for example).

closes #27

[khiav223577]

Hi Danieth,

Thank you for submitting your PR. I really appreciate your contribution and I'm looking forward to taking a closer look later. However, before that, could you please fix the indentation issue? Once that's done, I'll be able to review it more effectively. Thank you again for your hard work!

[Danieth]

Yes, it's fixed now!

[Danieth]

@khiav223577 bumping this for review.

I've realized, it may make sense to limit the scope of this solution to be less Postgres specific - an alternative solution might look like:

    case range_end
    when Float
      increase_float ? range_end.next_float : range_end
    when Time # ActiveSupport::TimeWithZone
      range_end
    else
      range_end + 1
    end

It would be a lot simpler. Just a thought.

[khiav223577]

The test case fails at Line 131. It may need to add require "active_support/isolated_execution_state" here?

The error message is:

ContainOverlapTest#test_active_support_time_with_timezone_overlaps:
NameError: uninitialized constant ActiveSupport::IsolatedExecutionState
    /home/runner/work/multi_range/multi_range/vendor/bundle/ruby/2.7.0/gems/activesupport-7.0.4.3/lib/active_support/core_ext/time/zones.rb:42:in `zone='
    /home/runner/work/multi_range/multi_range/test/contain_overlap_test.rb:131:in `test_active_support_time_with_timezone_overlaps'

[khiav223577]

MINOR: We don't have to reassign the value here.

Suggested change

	@ranges = @ranges.freeze
	@ranges.freeze

[khiav223577]

Others LGTM!