[#100689] [Ruby master Feature#17303] Make webrick to bundled gems or remove from stdlib — hsbt@...
Issue #17303 has been reported by hsbt (Hiroshi SHIBATA).
11 messages
2020/11/02
[#100852] [Ruby master Feature#17326] Add Kernel#must! to the standard library — zimmerman.jake@...
SXNzdWUgIzE3MzI2IGhhcyBiZWVuIHJlcG9ydGVkIGJ5IGpleiAoSmFrZSBaaW1tZXJtYW4pLg0K
24 messages
2020/11/14
[#100930] [Ruby master Feature#17333] Enumerable#many? — masafumi.o1988@...
Issue #17333 has been reported by okuramasafumi (Masafumi OKURA).
10 messages
2020/11/18
[#101071] [Ruby master Feature#17342] Hash#fetch_set — hunter_spawn@...
Issue #17342 has been reported by MaxLap (Maxime Lapointe).
26 messages
2020/11/25
[ruby-core:101056] [Ruby master Bug#17218] Range#step sometimes behaves unexpectedly with Rational endpoints and increment
From:
merch-redmine@...
Date:
2020-11-24 22:09:26 UTC
List:
ruby-core #101056
Issue #17218 has been updated by jeremyevans0 (Jeremy Evans).
This is caused by calling rb_int_plus/rb_int_mul/rb_int_minus directly instead of calling Ruby methods in arith_seq_last. I'm guessing the use of Rational begin/end/step was not anticipated. Calling Ruby methods seems to fix the issue. I've submitted a pull request with that approach: https://github.com/ruby/ruby/pull/3810
----------------------------------------
Bug #17218: Range#step sometimes behaves unexpectedly with Rational endpoints and increment
https://bugs.ruby-lang.org/issues/17218#change-88728
* Author: rorymolinari (Rory Molinari)
* Status: Assigned
* Priority: Normal
* Assignee: mrkn (Kenta Murata)
* ruby -v: ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-darwin19]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
I am using the latest stable version. The same behavior exists in 2.6.6.
```
11:28:25 $ ruby -v
ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-darwin19]
```
When creating an `Enumerator::ArithmeticSequence` with Rational endpoints and increment, sometimes inconsistent behavior results due to floating-point approximation in `#last`.
``` ruby
x = Rational(10997, 10000)
y = Rational(11, 10)
s = Rational(1, 10000)
puts "#{[x, y, s].map(&:to_f)}" # -> [1.0997, 1.1, 0.0001]
# intention: this contains exactly the precise Rational representations of 1.0997, 1.0998, 1.0999, 1.1
arith_seq = (x..y).step(s)
puts arith_seq.class # -> Enumerator::ArithmeticSequence
# Things look OK
puts arith_seq.first # -> 10997/10000
puts arith_seq.end # -> 11/10
puts arith_seq.step # -> 1/10000
# But the array that we get from #to_a is missing the last element, (11/10)
puts arith_seq.to_a.to_s # -> [(10997/10000), (5499/5000), (10999/10000)]
# This is apparently due to the value of #last
puts arith_seq.last # -> 1.0999999999999999
# The object itself is confused
puts arith_seq.size # -> 4
puts arith_seq.to_a.size # -> 3
```
The issue is in the `Enumerator::ArithmeticSequence` instance we get when we call `Range#step` without a block. The `Range#step` method passes the right things when it gets a block.
``` ruby
block_vals = []
(x..y).step(s) { |v| block_vals << v }
puts block_vals.to_s # -> [(10997/10000), (5499/5000), (10999/10000), (11/10)]
```
I would expect `arith_seq.last` to be the exact value `Rational(11, 10)`. After all, `arith_seq` was created from a `Range` with `Rational` endpoints and given a rational step size.
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