Although the Ractor API is still experimental and may change, and there
may be some implementation issues, we should no longer say that there
are many.
Hopefully we can remove this warning entirely for Ruby 4.1
```ruby
$VERBOSE = true
Ractor.store_if_absent :key do
end #=> warning: the block passed to 'Ractor.store_if_absent' defined at <internal:ractor>:474 may be ignored
```
call-seq:
Ractor.sharable_proc(self: nil){} -> sharable proc
It returns shareable Proc object. The Proc object is
shareable and the self in a block will be replaced with
the value passed via `self:` keyword.
In a shareable Proc, the outer variables should
* (1) refer shareable objects
* (2) be not be overwritten
```ruby
a = 42
Ractor.shareable_proc{ p a }
#=> OK
b = 43
Ractor.shareable_proc{ p b; b = 44 }
#=> Ractor::IsolationError because 'b' is reassigned in the block.
c = 44
Ractor.shareable_proc{ p c }
#=> Ractor::IsolationError because 'c' will be reassigned outside of the block.
c = 45
d = 45
d = 46 if cond
Ractor.shareable_proc{ p d }
#=> Ractor::IsolationError because 'd' was reassigned outside of the block.
```
The last `d`'s case can be relaxed in a future version.
The above check will be done in a static analysis at compile time,
so the reflection feature such as `Binding#local_varaible_set`
can not be detected.
```ruby
e = 42
shpr = Ractor.shareable_proc{ p e } #=> OK
binding.local_variable_set(:e, 43)
shpr.call #=> 42 (returns captured timing value)
```
Ractor.sharaeble_lambda is also introduced.
[Feature #21550]
[Feature #21557]
`Ractor#take` was deprecated but some libraries can use it as
an alias for `Ractor#value` (i.e., to wait for a Ractor's
temrination and retrieve its result).
Therefore `Ractor#take` is simply an alias for `Ractor#value`.
This method will remain available until the end of August 2025,
unless there is further discussion.
* Added `Ractor::Port`
* `Ractor::Port#receive` (support multi-threads)
* `Rcator::Port#close`
* `Ractor::Port#closed?`
* Added some methods
* `Ractor#join`
* `Ractor#value`
* `Ractor#monitor`
* `Ractor#unmonitor`
* Removed some methods
* `Ractor#take`
* `Ractor.yield`
* Change the spec
* `Racotr.select`
You can wait for multiple sequences of messages with `Ractor::Port`.
```ruby
ports = 3.times.map{ Ractor::Port.new }
ports.map.with_index do |port, ri|
Ractor.new port,ri do |port, ri|
3.times{|i| port << "r#{ri}-#{i}"}
end
end
p ports.each{|port| pp 3.times.map{port.receive}}
```
In this example, we use 3 ports, and 3 Ractors send messages to them respectively.
We can receive a series of messages from each port.
You can use `Ractor#value` to get the last value of a Ractor's block:
```ruby
result = Ractor.new do
heavy_task()
end.value
```
You can wait for the termination of a Ractor with `Ractor#join` like this:
```ruby
Ractor.new do
some_task()
end.join
```
`#value` and `#join` are similar to `Thread#value` and `Thread#join`.
To implement `#join`, `Ractor#monitor` (and `Ractor#unmonitor`) is introduced.
This commit changes `Ractor.select()` method.
It now only accepts ports or Ractors, and returns when a port receives a message or a Ractor terminates.
We removes `Ractor.yield` and `Ractor#take` because:
* `Ractor::Port` supports most of similar use cases in a simpler manner.
* Removing them significantly simplifies the code.
We also change the internal thread scheduler code (thread_pthread.c):
* During barrier synchronization, we keep the `ractor_sched` lock to avoid deadlocks.
This lock is released by `rb_ractor_sched_barrier_end()`
which is called at the end of operations that require the barrier.
* fix potential deadlock issues by checking interrupts just before setting UBF.
https://bugs.ruby-lang.org/issues/21262
Many libraries should be loaded on the main ractor because of
setting constants with unshareable objects and so on.
This patch allows to call `requore` on non-main Ractors by
asking the main ractor to call `require` on it. The calling ractor
waits for the result of `require` from the main ractor.
If the `require` call failed with some reasons, an exception
objects will be deliverred from the main ractor to the calling ractor
if it is copy-able.
Same on `require_relative` and `require` by `autoload`.
Now `Ractor.new{pp obj}` works well (the first call of `pp` requires
`pp` library implicitly).
[Feature #20627]
`Ractor::Selector` is not approved by Matz so remove it from
Ruby-level.
The implementation is used by `Ractor.select` so most of implementation
was remaind and calling `rb_init_ractor_selector()`, `Ractor::Selector`
will be defined. I will provide `ractor-selector` gem to try it.
This patch rewrites Ractor synchronization mechanism, send/receive
and take/yield.
* API
* Ractor::Selector is introduced for lightweight waiting
for many ractors.
* Data structure
* remove `struct rb_ractor_waiting_list` and use
`struct rb_ractor_queue takers_queue` to manage takers.
* remove `rb_ractor_t::yield_atexit` and use
`rb_ractor_t::sync::will_basket::type` to check the will.
* add `rb_ractor_basket::p.take` to represent a taking ractor.
* Synchronization protocol
* For the Ractor local GC, `take` can not make a copy object
directly so ask to generate the copy from the yielding ractor.
* The following steps shows what `r1.take` does on `r0`.
* step1: (r0) register `r0` into `r1`'s takers.
* step2: (r0) check `r1`'s status and wakeup r0 if `r1` is waiting
for yielding a value.
* step3: (r0) sleep until `r1` wakes up `r0`.
* The following steps shows what `Ractor.yield(v)` on `r1`.
* step1: (r1) check first takers of `r1` and if there is (`r0`),
make a copy object of `v` and pass it to `r0` and
wakes up `r0`.
* step2: (r1) if there is no taker ractors, sleep until
another ractor try to take.
* Make changes to docs in ractor.rb
Mainly English changes to make things more clear, and to fix minor
non-idiomatic phrases. Also clarified difference between frozen and
shareable objects.
* More minor changes to Ractor docs.
The internal location in ractor.rb is not usefull at all.
```
$ ruby -e 'Ractor.new {}'
<internal:ractor>:267: warning: Ractor is experimental, ...
```
* As the "doc/" prefix is specified by the `--page-dir` option,
remove from the rdoc references.
* Refer to the original .rdoc instead of the converted .html.
separate some fields from rb_ractor_t to rb_ractor_pub and put it
at the beggining of rb_ractor_t and declare it in vm_core.h so
vm_core.h can access rb_ractor_pub fields.
Now rb_ec_ractor_hooks() is a complete inline function and no
MJIT related issue.
Luke Gruber