[ruby-core:101572] [Ruby master Bug#17409] Endless range of dates stuck on include? when miss

Issue #17409 has been updated by gsmetal (Sergey G).


duerst (Martin Dst) wrote in #note-4:
> zverok (Victor Shepelev) wrote in #note-1:
> > Nothing specific to dates there, and not a bug.
> > 
> > This is just how ranges work:
> > * `range.include?(x)` is basically `range.each.any? {|el| el == x }`, which, with endless range, is an infinite loop
> > * `range.cover?(x)` is basically `x >= range.begin && x <= range.end`, which is instantaneous.
> > 
> > The behavior of `#include?` is redefined for Numeric and String, so `(1..).include?(0)` will behave like `cover?` (return `false` immediately), but with any other type, the behavior is the same as for Date.
> 
> What's the reason there is no redefinition for Date? Is there an actual use case for something like the current `(Date.today..).include?(Date.today - 1)` (of course with other actual values, because we don't need this to create an infinite loop)?


Yes, it was a little bit frustrating, that everything worked on numbers and then it unexpectedly stuck on dates.. This case with endless ranges should be at least somehow mentioned in `include?` documentation, I think. Now it doesn't seem very clear [here](https://ruby-doc.org/core-2.7.1/Range.html#method-i-include-3F).


----------------------------------------
Bug #17409: Endless range of dates stuck on include? when miss
https://bugs.ruby-lang.org/issues/17409#change-89357

* Author: gsmetal (Sergey G)
* Status: Rejected
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-linux]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
This code stucks (on latest ruby 2.7.1):
```ruby
require 'date'

(Date.today..).include?(Date.today - 1)
```

But it works well with `cover?`:
```ruby
2.7.1 :001 > require 'date'
 => true 
2.7.1 :002 > (Date.today..).cover?(Date.today - 1)
 => false 
```



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