NEWS for Ruby 3.1.0

This document is a list of user visible feature changes since the 3.0.0 release, except for bug fixes.

Note that each entry is kept to a minimum, see links for details.

Language changes

Pin operator now takes an expression. [Feature #17411]

Prime.each_cons(2).lazy.find_all{_1 in [n, ^(n + 2)]}.take(3).to_a
#=> [[3, 5], [5, 7], [11, 13]]

Outstanding ones only.

Enumerable
- Enumerable#compact is added. [Feature #17312]
- Enumerable#tally now accepts an optional hash to count. [Feature #17744]
Enumerator::Lazy
- Enumerator::Lazy#compact is added. [Feature #17312]
File
- File.dirname now accepts an optional argument for the level to strip path components. [Feature #12194]
Module
- Module#prepend now modifies the ancestor chain if the receiver already includes the argument. Module#prepend still does not modify the ancestor chain if the receiver has already prepended the argument. [Bug #17423]
Struct
- Passing only keyword arguments to Struct#initialize is warned. You need to use a Hash literal to set a Hash to a first member. [Feature #16806]
Queue
- Queue#initialize now accepts an Enumerable of initial values. [Feature #17327]
Thread::Backtrace
- Thread::Backtrace.limit, which returns the value to limit backtrace length set by --backtracse-limit command line option, is added. [Feature #17479]
$LOAD_PATH
- $LOAD_PATH.resolve_feature_path does not raise. [Feature #16043]

Outstanding ones only.

Excluding feature bug fixes.

ERB#initialize warns safe_level and later arguments even without -w. [Feature #14256]