[#48745] [ruby-trunk - Bug #7267][Open] Dir.glob on Mac OS X returns unexpected string encodings for unicode file names — "kennygrant (Kenny Grant)" <kennygrant@...>

17 messages 2012/11/02

[#48773] [ruby-trunk - Bug #7269][Open] Refinement doesn't work if using locate after method — "ko1 (Koichi Sasada)" <redmine@...>

12 messages 2012/11/03

[#48847] [ruby-trunk - Bug #7274][Open] UnboundMethods should be bindable to any object that is_a?(owner of the UnboundMethod) — "rits (First Last)" <redmine@...>

21 messages 2012/11/04

[#48854] [ruby-trunk - Bug #7276][Open] TestFile#test_utime failure — "jonforums (Jon Forums)" <redmine@...>

14 messages 2012/11/04

[#48988] [ruby-trunk - Feature #7292][Open] Enumerable#to_h — "marcandre (Marc-Andre Lafortune)" <ruby-core@...>

40 messages 2012/11/06

[#48997] [ruby-trunk - Feature #7297][Open] map_to alias for each_with_object — "nathan.f77 (Nathan Broadbent)" <nathan.f77@...>

19 messages 2012/11/06

[#49001] [ruby-trunk - Bug #7298][Open] Behavior of Enumerator.new different between 1.9.3 and 2.0.0 — "ayumin (Ayumu AIZAWA)" <ayumu.aizawa@...>

12 messages 2012/11/06

[#49018] [ruby-trunk - Feature #7299][Open] Ruby should not completely ignore blocks. — "marcandre (Marc-Andre Lafortune)" <ruby-core@...>

13 messages 2012/11/07

[#49044] [ruby-trunk - Bug #7304][Open] Random test failures around test_autoclose_true_closed_by_finalizer — "luislavena (Luis Lavena)" <luislavena@...>

11 messages 2012/11/07

[#49196] [ruby-trunk - Feature #7322][Open] Add a new operator name #>< for bit-wise "exclusive or" — "alexeymuranov (Alexey Muranov)" <redmine@...>

18 messages 2012/11/10

[#49211] [ruby-trunk - Feature #7328][Open] Move ** operator precedence under unary + and - — "boris_stitnicky (Boris Stitnicky)" <boris@...>

20 messages 2012/11/11

[#49229] [ruby-trunk - Bug #7331][Open] Set the precedence of unary `-` equal to the precedence `-`, same for `+` — "alexeymuranov (Alexey Muranov)" <redmine@...>

17 messages 2012/11/11

[#49256] [ruby-trunk - Feature #7336][Open] Flexiable OPerator Precedence — "trans (Thomas Sawyer)" <transfire@...>

18 messages 2012/11/12

[#49354] review open pull requests on github — Zachary Scott <zachary@...>

Could we get a review on any open pull requests on github before the

12 messages 2012/11/15
[#49355] Re: review open pull requests on github — "NARUSE, Yui" <naruse@...> 2012/11/15

2012/11/15 Zachary Scott <zachary@zacharyscott.net>:

[#49356] Re: review open pull requests on github — Zachary Scott <zachary@...> 2012/11/15

Ok, I was hoping one of the maintainers might want to.

[#49451] [ruby-trunk - Bug #7374][Open] File.expand_path resolving to first file/dir instead of absolute path — mdube@... (Martin Dubé) <mdube@...>

12 messages 2012/11/16

[#49463] [ruby-trunk - Feature #7375][Open] embedding libyaml in psych for Ruby 2.0 — "tenderlovemaking (Aaron Patterson)" <aaron@...>

21 messages 2012/11/16
[#49494] [ruby-trunk - Feature #7375] embedding libyaml in psych for Ruby 2.0 — "vo.x (Vit Ondruch)" <v.ondruch@...> 2012/11/17

[#49467] [ruby-trunk - Feature #7377][Open] #indetical? as an alias for #equal? — "aef (Alexander E. Fischer)" <aef@...>

13 messages 2012/11/17

[#49558] [ruby-trunk - Bug #7395][Open] Negative numbers can't be primes by definition — "zzak (Zachary Scott)" <zachary@...>

10 messages 2012/11/19

[#49566] [ruby-trunk - Feature #7400][Open] Incorporate OpenSSL tests from JRuby. — "zzak (Zachary Scott)" <zachary@...>

11 messages 2012/11/19

[#49770] [ruby-trunk - Feature #7414][Open] Now that const_get supports "Foo::Bar" syntax, so should const_defined?. — "robertgleeson (Robert Gleeson)" <rob@...>

9 messages 2012/11/20

[#49950] [ruby-trunk - Feature #7427][Assigned] Update Rubygems — "mame (Yusuke Endoh)" <mame@...>

17 messages 2012/11/24

[#50043] [ruby-trunk - Bug #7429][Open] Provide options for core collections to customize behavior — "headius (Charles Nutter)" <headius@...>

10 messages 2012/11/24

[#50092] [ruby-trunk - Feature #7434][Open] Allow caller_locations and backtrace_locations to receive negative params — "sam.saffron (Sam Saffron)" <sam.saffron@...>

21 messages 2012/11/25

[#50094] [ruby-trunk - Bug #7436][Open] Allow for a "granularity" flag for backtrace_locations — "sam.saffron (Sam Saffron)" <sam.saffron@...>

11 messages 2012/11/25

[#50207] [ruby-trunk - Bug #7445][Open] strptime('%s %z') doesn't work — "felipec (Felipe Contreras)" <felipe.contreras@...>

19 messages 2012/11/27

[#50424] [ruby-trunk - Bug #7485][Open] ruby cannot build on mingw32 due to missing __sync_val_compare_and_swap — "drbrain (Eric Hodel)" <drbrain@...7.net>

15 messages 2012/11/30

[#50429] [ruby-trunk - Feature #7487][Open] Cutting through the issues with Refinements — "trans (Thomas Sawyer)" <transfire@...>

13 messages 2012/11/30

[ruby-core:49447] [ruby-trunk - Bug #2121] mathn/rational destroys Fixnum#/, Fixnum#quo and Bignum#/, Bignum#quo

From: "marcandre (Marc-Andre Lafortune)" <ruby-core@...>
Date: 2012-11-16 17:39:33 UTC
List: ruby-core #49447
Issue #2121 has been updated by marcandre (Marc-Andre Lafortune).

Description updated
Category set to lib

It does create some problems in real apps (e.g. https://github.com/rails/rails/pull/8222 )

The problem is compatibility. I always thought that it was the intent of `mathn` to change the semantics of `/` so that the same operations would have different meanings. For example `Matrix[[1]] / 2` returns different results depending on the presence of `mathn` or not.

Avoiding the problem is trivial: when you mean "division with truncation to integer", use `Integer#div` instead of `Integer#/`.

`div` has the advantage of being crystal clear, since `foo.div(bar)` always truncates down to an integer, while `foo / bar` can return any of Integer, Rational, Float, BigDecimal, Complex, Matrix, Vector, etc., depending on the classes of foo, bar (and if mathn is loaded or not)

What I'm trying to say is that, given the choices made in the past, using `/` instead of `div` can be seen as a user mistake, although it clearly is an easy one to make. Ideally, library/framework authors would be aware of this and reserve `Integer#/` for mathematical libraries and use `div` where appropriate.

I don't see how we can change the current behavior, but adding a note in the doc for `Integer#/` about this could not hurt.

----------------------------------------
Bug #2121: mathn/rational destroys Fixnum#/, Fixnum#quo and Bignum#/, Bignum#quo
https://bugs.ruby-lang.org/issues/2121#change-32984

Author: headius (Charles Nutter)
Status: Assigned
Priority: Normal
Assignee: keiju (Keiju Ishitsuka)
Category: lib
Target version: 
ruby -v: Any 1.8.6 or higher


=begin
 I've known this for a while, but only now realized this is actually a terrible bug.
 
 The mathn library replaces Fixnum#/ and Bignum#/ causing them to return a different value. When the result of a division is not an integral value, the default versions will return 0. I can think of many algorithms that would use this expectation, and most other languages will not upconvert integral numeric types to floating-point or fractional types without explicit consent by the programmer.
 
 When requiring 'mathn', Fixnum#/ and Bignum#/ are replaced with versions that return a fractional value ('quo') causing a core math operator to return not just a different type, but *a different value*.
 
 No core library should be allowed to modify the return value of core numeric operators, or else those operators are worthless; you can't rely on them to return a specific value *ever* since someone else could require 'mathn' or 'rational'.
 
 Note also that 'rational' destroys Fixnum#quo and Bignum#quo. This is also a bug that should be fixed, though it is less dangerous because they're not commonly-used operators.
 
 The following code should not fail; Fixnum#/ should never return a value of a different magnitude based on which libraries are loaded:
 
 {{{
 require 'test/unit'
 
 class TestFixnumMath < Test::Unit::TestCase
   # 0 to ensure it runs first, for illustration purposes
   def test_0_without_mathn
     assert_equal 0, 1/3
   end
 
   def test_with_mathn
     require 'mathn'
     assert_equal 0, 1/3
   end
 end
 }}}
 
 But it does fail:
 
 {{{
 ~/projects/jruby ➔ ruby test_fixnum_math.rb 
 Loaded suite test_fixnum_math
 Started
 .F
 Finished in 0.016003 seconds.
 
   1) Failure:
 test_with_mathn(TestFixnumMath) [test_fixnum_math.rb:11]:
 <0> expected but was
 <1/3>.
 
 2 tests, 2 assertions, 1 failures, 0 errors
 }}}
=end



-- 
http://bugs.ruby-lang.org/

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