Inconsistent occurrences_between behaviour on weekly intervals

[hughkelsey]

Lots of head scratching going on here...

I have a rule for 3 days every other week and occurrences_between gives me the correct result when I look for occurrences +/- 7 days from an expected date and +/- 1 day but I get an incorrect result when looking +/- 5 or 6 days.

require 'ice_cube'
IceCube::VERSION # "0.12.0" 

start_date = Date.parse('2014-01-08')
schedule = IceCube::Schedule.new(start_date)
schedule.add_recurrence_rule IceCube::Rule.weekly(2).day([4,5,6])

expected = Date.parse('2014-07-24') # Thursday

schedule.occurs_on?(expected) # true

schedule.occurrences_between(expected - 7, expected + 7).include?(expected.to_time) # true
schedule.occurrences_between(expected - 1, expected + 1).include?(expected.to_time) # true
schedule.occurrences_between(expected - 6, expected + 6).include?(expected.to_time) # false
schedule.occurrences_between(expected - 6, expected + 1).include?(expected.to_time) # false
schedule.occurrences_between(expected - 5, expected + 6).include?(expected.to_time) # false
schedule.occurrences_between(expected - 1, expected + 6).include?(expected.to_time) # true
schedule.occurrences_between(expected - 4, expected + 6).include?(expected.to_time) # true

I've forked ice_cube and added a failing spec (pr to follow).

describe 'weekly schedule with interval' do
  let(:schedule) {Schedule.new('2014-01-08'.to_date)}
  let(:expected_occurrence) {'2014-07-24'.to_date.to_time}

  before :each do
    schedule.add_recurrence_rule Rule.weekly(2).day([4,5,6])
  end
  it "should include the expected date" do
    expect(schedule.occurs_on?(expected_occurrence)).to be_true
    expect(schedule.occurrences_between(expected_occurrence - 7.days, expected_occurrence + 7.days)).to include(expected_occurrence)
    expect(schedule.occurrences_between(expected_occurrence - 1.day, expected_occurrence + 1.day)).to include(expected_occurrence)
    expect(schedule.occurrences_between(expected_occurrence - 6.days, expected_occurrence + 6.days)).to include(expected_occurrence) # fails here
    expect(schedule.occurrences_between(expected_occurrence - 5.days, expected_occurrence + 5.days)).to include(expected_occurrence)
  end
end

[avit]

Very interesting... thanks for reporting. I'll try to have a look at this tonight.

[hughkelsey]

It is a a weird one for sure. Let me know if there are any other areas I can add some tests to track down the issue.

Thanks for the AWESOME Gem!

H

On Jun 10, 2014, at 12:05 PM, Andrew Vit notifications@github.com wrote:

Very interesting... thanks for reporting. I'll try to have a look at this tonight.

—
Reply to this email directly or view it on GitHub.

[hughkelsey]

I tried a couple more variations on the code above with similar results.

As the error occurs in the 6/7 day range I tried next_occurrences and previous_occurrences. It appeared in next_occurrences and not in previous_occurrences. This is in line with the findings above where it's the occurrence range starting 6/7 days before the expected date returning false. I also wondered if this cropped up every second week but it doesn't, the last line goes back 100 days and only returns false on day 6 and 7.

require 'ice_cube'
IceCube::VERSION # "0.12.0" 

start_date = Date.parse('2014-01-08')
schedule = IceCube::Schedule.new(start_date)
schedule.add_recurrence_rule IceCube::Rule.weekly(2).day([4,5,6])

expected = Date.parse('2014-07-24') # Thursday

schedule.occurs_on?(expected) # true

schedule.next_occurrences(10, (expected - 4).to_time).include?(expected.to_time) # true
schedule.next_occurrences(10, (expected - 5).to_time).include?(expected.to_time) # true
schedule.next_occurrences(10, (expected - 6).to_time).include?(expected.to_time) # false
schedule.next_occurrences(10, (expected - 7).to_time).include?(expected.to_time) # false
schedule.next_occurrences(10, (expected - 8).to_time).include?(expected.to_time) # true
schedule.next_occurrences(20, (expected - 13).to_time).include?(expected.to_time) # true
schedule.next_occurrences(20, (expected - 14).to_time).include?(expected.to_time) # true
schedule.next_occurrences(20, (expected - 15).to_time).include?(expected.to_time) # true

schedule.previous_occurrences(10, (expected + 7).to_time).include?(expected.to_time) # true
schedule.previous_occurrences(10, (expected + 6).to_time).include?(expected.to_time) # true

(1..100).each {|n| puts n, schedule.next_occurrences(n, (expected - n).to_time).include?(expected.to_time)}

[hughkelsey]

Hi @avit, have you been able to look in to this at all?

I've been reading through quite a bit of the source and feel a bit out of my element. Are there any more specific areas I could test that might help narrow down this issue?

Thanks!

[avit]

Hi again,

I did have another look at this last weekend, but it needs some deeper debugging. I had to work backwards by altering your tests to bring the dates closer together from the start time to the problem time in order to narrow it down. (Surprisingly it's not Daylight Savings Time, for once...)

I have some ideas where to look next, I just need some time to dive into it.

[avit]

@hughkelsey I have a fix for this in my branch https://github.com/avit/ice_cube/tree/issues/241

Still looking at it to see if there are other places this could happen, or if the change affects anything badly before merging. Please have a look.

[avit]

Merged the fix, looks good to me!