From: universato@gmail.com
To: ruby-core@ruby-lang.org
Subject: [ruby-core:100348] [Ruby master Bug#17257] Integer#pow(0, 1) returns 1, which is incorrect
Date: Fri, 09 Oct 2020 14:18:43 +0000 (UTC) [thread overview]
Message-ID: <redmine.issue-17257.20201009141843.45098@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-17257.20201009141843.45098@ruby-lang.org
Issue #17257 has been reported by universato (Yoshimine Sato).
----------------------------------------
Bug #17257: Integer#pow(0, 1) returns 1, which is incorrect
https://bugs.ruby-lang.org/issues/17257
* Author: universato (Yoshimine Sato)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
Ruby 2.5.8, 2.6.6, 2.7.1
```ruby
p -1.pow(0, 1) #=> 1
p 0.pow(0, 1) #=> 1
p 1.pow(0, 1) #=> 1
p 1234567890.pow(0, 1) #=> 1
```
These return value shoud be 0.
Patch for test:
Let's add some boundary value tests to `test_pow` of [test_numeric.rb](https://github.com/ruby/ruby/blob/e014e6bf6685f681998238ff005f6d161d43ce51/test/ruby/test_numeric.rb).
```ruby
integers = [-2, -1, 0, 1, 2, 3, 6, 1234567890123456789]
integers.each do |i|
assert_equal(0, i.pow(0, 1), '[Bug #17257]')
assert_equal(1, i.pow(0, 2))
assert_equal(1, i.pow(0, 3))
assert_equal(1, i.pow(0, 6))
assert_equal(1, i.pow(0, 1234567890123456789))
assert_equal(0, i.pow(0, -1))
assert_equal(-1, i.pow(0, -2))
assert_equal(-2, i.pow(0, -3))
assert_equal(-5, i.pow(0, -6))
assert_equal(-1234567890123456788, i.pow(0, -1234567890123456789))
end
assert_equal(0, 0.pow(2, 1))
assert_equal(0, 0.pow(3, 1))
assert_equal(0, 2.pow(3, 1))
assert_equal(0, -2.pow(3, 1))
--
https://bugs.ruby-lang.org/
next parent reply other threads:[~2020-10-09 14:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 14:18 universato [this message]
2020-10-10 6:54 ` [ruby-core:100355] [Ruby master Bug#17257] Integer#pow(0, 1) returns 1, which is incorrect nobu
2020-10-10 9:18 ` [ruby-core:100356] " universato
2020-10-10 18:12 ` [ruby-core:100359] " midnight_w
2020-10-10 19:28 ` [ruby-core:100361] " marcandre-ruby-core
2020-10-11 2:48 ` [ruby-core:100363] " nobu
2020-10-11 3:32 ` [ruby-core:100365] " midnight_w
2020-10-11 3:41 ` [ruby-core:100366] " midnight_w
2020-10-11 5:54 ` [ruby-core:100367] " universato
2020-10-11 12:09 ` [ruby-core:100373] " sawadatsuyoshi
2020-10-11 13:18 ` [ruby-core:100374] " midnight_w
2020-10-11 18:46 ` [ruby-core:100375] " universato
2020-10-12 4:35 ` [ruby-core:100379] " mame
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