From: matz@... Date: 2020-09-01T05:13:22+00:00 Subject: [ruby-core:99813] [Ruby master Bug#17017] Range#max & Range#minmax incorrectly use Float end as max Issue #17017 has been updated by matz (Yukihiro Matsumoto). `Range` class methods are classified in two. The ones that behave like `Enumerable` methods (defined by `#each`), and the others that behave like region (defined by the both ends). I think `#min` and `#max` should belong to the latter. So the old behavior is preferable, that is `(1..3.5).max #=> 3.5`. Matz. ---------------------------------------- Bug #17017: Range#max & Range#minmax incorrectly use Float end as max https://bugs.ruby-lang.org/issues/17017#change-87335 * Author: sambostock (Sam Bostock) * Status: Closed * Priority: Normal * ruby -v: ruby 2.8.0dev (2020-07-14T04:19:55Z master e60cd14d85) [x86_64-darwin17] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- While continuing to add edge cases to [`Range#minmax` specs](https://github.com/ruby/spec/pull/777), I discovered the following bug: ```ruby (1..3.1).to_a == [1, 2, 3] # As expected (1..3.1).to_a.max == 3 # As expected (1..3.1).to_a.minmax == [1, 3] # As expected (1..3.1).max == 3.1 # Should be 3, as above (1..3.1).minmax == [1, 3.1] # Should be [1, 3], as above ``` One way to detect this scenario might be to do (whatever the C equivalent is of) ```ruby range_end.is_a?(Numeric) // Is this a numeric range? && (range_end - range_begin).modulo(1) == 0 // Can we reach the range_end using the standard step size (1) ``` As for how to handle it, a couple options come to mind: - We could error out and do something similar to what we do for exclusive ranges ```ruby raise TypeError, 'cannot exclude non Integer end value' ``` - We might be able to calculate the range end by doing something like ```ruby num_steps = (range_end / range_beg).to_i - 1 # one fewer steps than would exceed the range_end max = range_beg + num_steps # take that many steps all at once ``` - We could delegate to `super` and enumerate the range to find the max ```ruby super ``` - We could update the documentation to define the max for this case as the `range_end`, similarly to how the documentation for `include?` says it behaves like `cover?` for numeric ranges. -- https://bugs.ruby-lang.org/ Unsubscribe: