1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
|
# -*- rdoc -*-
= NEWS for Ruby 2.7.0
This document is a list of user visible feature changes made between
releases except for bug fixes.
Note that each entry is kept so brief that no reason behind or reference
information is supplied with. For a full list of changes with all
sufficient information, see the ChangeLog file or Redmine
(e.g. <tt>https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER</tt>)
== Changes since the 2.6.0 release
=== Language changes
==== Pattern matching
* Pattern matching is introduced as an experimental feature. [Feature #14912]
case [0, [1, 2, 3]]
in [a, [b, *c]]
p a #=> 0
p b #=> 1
p c #=> [2, 3]
end
case {a: 0, b: 1}
in {a: 0, x: 1}
:unreachable
in {a: 0, b: var}
p var #=> 1
end
json = <<END
{
"name": "Alice",
"age": 30,
"children": [{ "name": "Bob", "age": 2 }]
}
END
if JSON.parse(json, symbolize_names: true) in
{name: "Alice", children: [{name: "Bob", age: age}]}
p age #=> 2
end
* See the following slides in detail
* https://speakerdeck.com/k_tsj/pattern-matching-new-feature-in-ruby-2-dot-7
==== The spec of keyword arguments is changed towards 3.0
* Automatic conversion of keyword arguments and positional arguments is
deprecated, and conversion will be removed in Ruby 3. [Feature #14183]
* When a method call passes a Hash at the last argument, and when it
passes no keywords, and when the called method accepts keywords, a
warning is emitted. To continue treating as keywords, add a double
splat operator to avoid the warning and ensure correct behavior in
Ruby 3.
def foo(key: 42); end; foo({key: 42}) # warned
def foo(**kw); end; foo({key: 42}) # warned
def foo(key: 42); end; foo(**{key: 42}) # OK
def foo(**kw); end; foo(**{key: 42}) # OK
* When a method call passes keywords to a method that accepts keywords,
but it does not pass enough required positional arguments, the
keywords are treated as a final required positional argument, and a
warning is emitted. Pass the argument as a hash instead of keywords
to avoid the warning and ensure correct behavior in Ruby 3.
def foo(h, **kw); end; foo(key: 42) # warned
def foo(h, key: 42); end; foo(key: 42) # warned
def foo(h, **kw); end; foo({key: 42}) # OK
def foo(h, key: 42); end; foo({key: 42}) # OK
* When a method accepts specific keywords but not a keyword splat, and
a hash or keywords splat is passed to the method that includes both
Symbol and non-Symbol keys, the hash will continue to be split, and
a warning will be emitted. You will need to update the calling code
to pass separate hashes to ensure correct behavior in Ruby 3.
def foo(h={}, key: 42); end; foo("key" => 43, key: 42) # warned
def foo(h={}, key: 42); end; foo({"key" => 43, key: 42}) # warned
def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK
def foo(h={}, key: 42); end; foo({"key" => 43}, key: 42) # OK
* If a method does not accept keywords, and is called with keywords,
the keywords are still treated as a positional hash, with no warning.
This behavior will continue to work in Ruby 3.
def foo(opt={}); end; foo( key: 42 ) # OK
* Non-symbols are allowed as a keyword argument keys if method accepts
arbitrary keywords. [Feature #14183]
* Non-Symbol keys in a keyword arguments hash were prohibited in 2.6.0,
but are now allowed again. [Bug #15658]
def foo(**kw); p kw; end; foo("str" => 1) #=> {"str"=>1}
* <code>**nil</code> is allowed in method definitions to explicitly mark
that the method accepts no keywords. Calling such a method with keywords
will result in an ArgumentError. [Feature #14183]
def foo(h, **nil); end; foo(key: 1) # ArgumentError
def foo(h, **nil); end; foo(**{key: 1}) # ArgumentError
def foo(h, **nil); end; foo("str" => 1) # ArgumentError
def foo(h, **nil); end; foo({key: 1}) # OK
def foo(h, **nil); end; foo({"str" => 1}) # OK
* Passing an empty keyword splat to a method that does not accept keywords
no longer passes an empty hash, unless the empty hash is necessary for
a required parameter, in which case a warning will be emitted. Remove
the double splat to continue passing a positional hash. [Feature #14183]
h = {}; def foo(*a) a end; foo(**h) # []
h = {}; def foo(a) a end; foo(**h) # {} and warning
h = {}; def foo(*a) a end; foo(h) # [{}]
h = {}; def foo(a) a end; foo(h) # {}
==== Numbered parameter
* Numbered parameter as the default block parameter is introduced as an
experimental feature. [Feature #4475]
[1, 2, 10].map { _1.to_s(16) } #=> ["1", "2", "a"]
==== proc/lambda without block is deprecated
* Proc.new and Kernel#proc with no block in a method called with a block is
warned now.
def foo
proc
end
foo { puts "Hello" } #=> warning: Capturing the given block using Proc.new is deprecated; use `&block` instead
* Kernel#lambda with no block in a method called with a block raises an exception.
def bar
lambda
end
bar { puts "Hello" } #=> tried to create Proc object without a block (ArgumentError)
==== Other miscellaneous changes
* A beginless range is experimentally introduced. It might not be as useful
as an endless range, but would be good for DSL purpose. [Feature #14799]
ary[..3] # identical to ary[0..3]
where(sales: ..100)
* Setting <code>$;</code> to non-nil value is warned now. Use of it in
String#split is warned too.
* Setting <code>$,</code> to non-nil value is warned now. Use of it in
Array#join is warned too.
* Quoted here-document identifier must end within the same line.
<<"EOS
" # This had been warned since 2.4; Now it raises a SyntaxError
EOS
* The flip-flop syntax deprecation is reverted. [Feature #5400]
* Comment lines can be placed between fluent dot now.
foo
# .bar
.baz # => foo.baz
* Calling a private method with a literal <code>self</code> as the receiver
is now allowed. [Feature #11297] [Feature #16123]
* Modifier rescue now operates the same for multiple assignment as single
assignment:
a, b = raise rescue [1, 2]
# Previously parsed as: (a, b = raise) rescue [1, 2]
# Now parsed as: a, b = (raise rescue [1, 2])
* Method reference operator, <code>.:</code> is introduced as an
experimental feature. [Feature #12125] [Feature #13581]
* +yield+ in singleton class syntax is warned and will be deprecated later [Feature #15575].
=== Core classes updates (outstanding ones only)
Array::
New method::
* Added Array#intersection. [Feature #16155]
Comparable::
Modified method::
* Comparable#clamp now accepts a Range argument. [Feature #14784]
-1.clamp(0..2) #=> 0
1.clamp(0..2) #=> 1
3.clamp(0..2) #=> 2
Complex::
New method::
* Added Complex#<=>. So 0 <=> 0i will not raise NoMethodError. [Bug #15857]
Dir::
Modified method::
* Dir.glob and Dir.[] no longer allow NUL-separated glob pattern.
Use Array instead. [Feature #14643]
Encoding::
New method::
* Added new encoding CESU-8 [Feature #15931]
Enumerable::
New methods::
* Added Enumerable#filter_map. [Feature #15323]
[1, 2, 3].filter_map {|x| x.odd? ? x.to_s : nil } #=> ["1", "3"]
* Added Enumerable#tally. [Feature #11076]
["A", "B", "C", "B", "A"].tally #=> {"A"=>2, "B"=>2, "C"=>1}
Enumerator::
New method::
* Added Enumerator::Lazy#eager that generates a non-lazy enumerator
from a lazy enumerator. [Feature #15901]
* Added Enumerator::Yielder#to_proc so that a Yielder object
can be directly passed to another method as a block
argument. [Feature #15618]
Fiber::
New method::
* Added Fiber#raise that behaves like Fiber#resume but raises an
exception on the resumed fiber. [Feature #10344]
File::
Modified method::
* File.extname now returns a dot string at a name ending with a dot on
non-Windows platforms. [Bug #15267]
File.extname("foo.") #=> "."
FrozenError::
New method::
* Added FrozenError#receiver to return the frozen object that
modification was attempted on. To set this object when raising
FrozenError in Ruby code, pass it as the second argument to
FrozenError.new.
GC::
New method::
* Added GC.compact method for compacting the heap.
This function compacts live objects in the heap so that fewer pages may
be used, and the heap may be more CoW friendly. [Feature #15626]
Details on the algorithm and caveats can be found here:
https://bugs.ruby-lang.org/issues/15626
IO::
New method::
* Added IO#set_encoding_by_bom to check the BOM and set the external
encoding. [Bug #15210]
Integer::
Modified method::
* Integer#[] now supports range operation. [Feature #8842]
0b01001101[2, 4] #=> 0b0011
0b01001100[2..5] #=> 0b0011
0b01001100[2...6] #=> 0b0011
^^^^
NilClass / TrueClass / FalseClass::
Modified method::
* NilClass#to_s, TrueClass#to_s and FalseClass#to_s now always returns a
frozen String. The returned String is always the same for each of these
values. This change is experimental. [Feature #16150]
Module::
New method::
* Added Module#const_source_location to retrieve the location where a
constant is defined. [Feature #10771]
* Added Module#ruby2_keywords for marking a method as passing keyword
arguments through a regular argument splat, useful when delegating
all arguments to another method in a way that can be backwards
compatible with older Ruby versions. [Bug #16154]
Modified method::
* Module#autoload? now takes an +inherit+ optional argument, like as
Module#const_defined?. [Feature #15777]
* Module#name now always return a frozen String. The returned String is
always the same for a given Module. This change is
experimental. [Feature #16150]
ObjectSpace::WeakMap::
Modified method::
* ObjectSpace::WeakMap#[]= now accepts special objects as either key or
values. [Feature #16035]
Regexp / String::
* Update Unicode version and Emoji version from 11.0.0 to
12.0.0. [Feature #15321]
* Update Unicode version to 12.1.0, adding support for
U+32FF SQUARE ERA NAME REIWA. [Feature #15195]
RubyVM::
Removed method::
* +RubyVM.resolve_feature_path+ moved to
<code>$LOAD_PATH.resolve_feature_path</code>. [Feature #15903] [Feature #15230]
Symbol::
Modified method::
* Symbol#to_s now always returns a frozen String. The returned String
is always the same for a given Symbol. This change is
experimental. [Feature #16150]
Time::
New methods::
* Added Time#ceil method. [Feature #15772]
* Added Time#floor method. [Feature #15653]
Modified method::
* Time#inspect is separated from Time#to_s and it shows its sub
second. [Feature #15958]
UnboundMethod::
New method::
* Added UnboundMethod#bind_call method. [Feature #15955]
<code>umethod.bind_call(obj, ...)</code> is semantically equivalent
to <code>umethod.bind(obj).call(...)</code>. This idiom is used in
some libraries to call a method that is overridden. The added
method does the same without allocation of intermediate Method
object.
class Foo
def add_1(x)
x + 1
end
end
class Bar < Foo
def add_1(x) # override
x + 2
end
end
obj = Bar.new
p obj.add_1(1) #=> 3
p Foo.instance_method(:add_1).bind(obj).call(1) #=> 2
p Foo.instance_method(:add_1).bind_call(obj, 1) #=> 2
$LOAD_PATH::
New method::
* Added <code>$LOAD_PATH.resolve_feature_path</code>. [Feature #15903] [Feature #15230]
=== Stdlib updates (outstanding ones only)
Bundler::
* Upgrade to Bundler 2.1.0.pre.1
Bundled from https://github.com/bundler/bundler/commit/a53709556b95a914e874b22ed2116a46b0528852
CGI::
* CGI.escapeHTML becomes 2~5x faster when there's at least one escaped character.
CSV::
* Upgrade to 3.1.2.
See https://github.com/ruby/csv/blob/master/NEWS.md.
Date::
* Date.jisx0301, Date#jisx0301, and Date.parse support the new Japanese
era. [Feature #15742]
Delegator::
* Object#DelegateClass accepts a block and module_evals it in the context
of the returned class, similar to Class.new and Struct.new.
ERB::
* Prohibit marshaling ERB instance.
IRB::
* Introduce syntax highlight inspired by pry.gem to Binding#irb source lines,
REPL input, and inspect output of some core-class objects.
* Introduce multiline mode by Reline.
* Show documents when completion.
* Enable auto indent and save/load history by default.
Net::FTP::
* Add features and options. [Feature #15964]
Net::IMAP::
* Add Server Name Indication (SNI) support. [Feature #15594]
open-uri::
* Warn open-uri's "open" method at Kernel.
Use URI.open instead. [Misc #15893]
* The default charset of text/* media type is UTF-8 instead of
ISO-8859-1. [Bug #15933]
OptionParser::
* Now show "Did you mean?" for unknown option. [Feature #16256]
test.rb:
require 'optparse'
OptionParser.new do |opts|
opts.on("-f", "--foo", "foo") {|v| }
opts.on("-b", "--bar", "bar") {|v| }
opts.on("-c", "--baz", "baz") {|v| }
end.parse!
example:
$ ruby test.rb --baa
Traceback (most recent call last):
test.rb:7:in `<main>': invalid option: --baa (OptionParser::InvalidOption)
Did you mean? baz
bar
Pathname::
* Delegates 3 arguments from Pathname.glob to Dir.glob to
accept base: keyword.
Racc::
* Merge 1.4.15 from upstream repository and added cli of racc.
Reline::
* New stdlib that is compatible with readline stdlib by pure Ruby and also
has a multiline mode.
REXML::
* Upgrade to 3.2.3.
See https://github.com/ruby/rexml/blob/master/NEWS.md.
RSS::
* Upgrade to RSS 0.2.8.
See https://github.com/ruby/rss/blob/master/NEWS.md.
RubyGems::
* Upgrade to RubyGems 3.1.0.pre1
Bundled from https://github.com/rubygems/rubygems/commit/97b264f0fa248c864b6ee9a23d3ff1cdd217dddb
StringScanner::
* Upgrade to 1.0.3.
See https://github.com/ruby/strscan/blob/master/NEWS.md.
=== Compatibility issues (excluding feature bug fixes)
* The following libraries are no longer bundled gems.
Install corresponding gems to use these features.
* CMath
* Scanf
* Shell
* Synchronizer
* ThreadsWait
Proc::
* Proc#to_s format was changed. [Feature #16101]
=== Stdlib compatibility issues (excluding feature bug fixes)
pathname::
* Kernel#Pathname when called with a Pathname argument now returns
the argument instead of creating a new Pathname. This is more
similar to other Kernel methods, but can break code that modifies
the return value and expects the argument not to be modified.
profile.rb, Profiler__::
* Removed from standard library. No one maintains it from Ruby 2.0.0.
=== C API updates
* Many <code>*_kw</code> functions have been added for setting whether
the final argument being passed should be treated as keywords. You
may need to switch to these functions to avoid keyword argument
separation warnings, and to ensure correct behavior in Ruby 3.
* The <code>:</code> character in rb_scan_args format string is now
treated as keyword arguments. Passing a positional hash instead of
keyword arguments will emit a deprecation warning.
* C API declarations with +ANYARGS+ are changed not to use +ANYARGS+
https://github.com/ruby/ruby/pull/2404
=== Implementation improvements
Fiber::
* Allow selecting different coroutine implementation by using
`--with-coroutine=`, e.g.
./confgure --with-coroutine=ucontext
./confgure --with-coroutine=copy
* Replace previous stack cache with fiber pool cache. The fiber pool
allocates many stacks in a single memory region. Stack allocation
becomes O(log N) and fiber creation is amortized O(1). Around 10x
performance improvement was measured in micro-benchmarks.
File::
* File.realpath now uses realpath(3) on many platforms, which can
significantly improve performance.
Hash::
* Change data structure of small Hash objects. [Feature #15602]
Monitor::
* Monitor class is written in C-extension. [Feature #16255]
Thread::
* VM stack memory allocation is now combined with native thread stack,
improving thread allocation performance and reducing allocation related
failures. ~10x performance improvement was measured in micro-benchmarks.
JIT::
* JIT-ed code is recompiled to less-optimized code when an optimization assumption is invalidated.
* Method inlining is performed when a method is considered as pure.
This optimization is still experimental and many methods are NOT considered as pure yet.
* Default value of +--jit-max-cache+ is changed from 1,000 to 100
* Default value of +--jit-min-calls+ is changed from 5 to 10,000
=== Miscellaneous changes
* Support for IA64 architecture has been removed. Hardware for testing was
difficult to find, native fiber code is difficult to implement, and it added
non-trivial complexity to the interpreter. [Feature #15894]
* Require compilers to support C99 [Misc #15347]
* Details of our dialect: https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/C99
* Ruby's upstream repository is changed from Subversion to Git.
* https://git.ruby-lang.org/ruby.git
* RUBY_REVISION class is changed from Integer to String.
* RUBY_DESCRIPTION includes Git revision instead of Subversion's one.
|