Bug #3089
limited size for Array#combination [patch]
| Status: | Closed | Start date: | 04/03/2010 | |
|---|---|---|---|---|
| Priority: | Low | Due date: | ||
| Assignee: |  matz (Yukihiro Matsumoto) |
% Done: | 100% |
|
| Category: | core | |||
| Target version: | 1.9.2 | |||
| ruby -v: | ruby 1.9.2dev (2010-04-03 trunk 27200) [x86_64-darwin10.2.0] |
Description
I would expect the following to work, but it raises an error (0..100).to_a.combination(50).first(42) # => RangeError: too big for combination There is a limit of 1 << 31 potential results (or 1 <<63, depending on the platform). Since there is an explicit test for this, I learned the hard way I better ask if there is a valid reason for this artificial limit for #combination ? If not, and unless there is objection, I'll commit the attached patch. Note: I noticed this when implementing the block form of #product where a similar limit exists. Since #product without a block needs to return an array of this size, it is sensible that an error is raised in that case. When an block is given, though, I didn't see why there should be a limit, so the limitation applies only to the form without a block. This does mean, though, that arr.product(...) might not behave the same as arr.to_enum(:product, ...).to_a, at least until Enumerators have a length method (see issue #2673)
Associated revisions
* array.c (rb_ary_product): Don't limit based on size when a block is given
cf [ruby-core:29240]
* test/ruby/test_array.rb (class): Test for above
* array.c (rb_ary_permutation): Remove limitation for lengthy permutations
[ruby-core:29240]
* test/ruby/test_array.rb: ditto
History
Updated by yugui (Yuki Sonoda) about 2 years ago
- Assignee set to matz (Yukihiro Matsumoto)
> I learned the hard way I better ask if there is a valid reason for this artificial limit for #combination ? hmm, matz, is this behavior intended? If not, I regard the limitation as a bug. It means, The patch can be merged into ruby 1.9.2.
Updated by matz (Yukihiro Matsumoto) about 2 years ago
Hi, In message "Re: [ruby-core:29241] [Bug #3089] limited size for Array#combination [patch]" on Sun, 4 Apr 2010 07:32:44 +0900, Yuki Sonoda <redmine@ruby-lang.org> writes: |> I learned the hard way I better ask if there is a valid reason for this artificial limit for #combination ? | |hmm, matz, is this behavior intended? If not, I regard the limitation as a bug. It means, The patch can be merged into ruby 1.9.2. It's not intended, so that the patch can be applied. Will you apply? matz.
Updated by marcandre (Marc-Andre Lafortune) about 2 years ago
- Status changed from Open to Closed
- % Done changed from 0 to 100
This issue was solved with changeset r27252. Marc-Andre, thank you for reporting this issue. Your contribution to Ruby is greatly appreciated. May Ruby be with you.