[#114774] [Ruby master Feature#19884] Make Safe Navigation Operator work on classes — "p8 (Petrik de Heus) via ruby-core" <ruby-core@...>
Issue #19884 has been reported by p8 (Petrik de Heus).
13 messages
2023/09/15
[ruby-core:114865] [Ruby master Bug#18911] Process._fork hook point is not called when Process.daemon is used
From:
"Dan0042 (Daniel DeLorme) via ruby-core" <ruby-core@...>
Date:
2023-09-21 18:30:17 UTC
List:
ruby-core #114865
Issue #18911 has been updated by Dan0042 (Daniel DeLorme).
Note for future readers coming here from the `Process._fork` documentation.
If you need to restart threads, you should override both `_fork` and `daemon`
```ruby
module RestartWatcherThread
def _fork
pid = super
restart_thread if pid == 0
pid
end
def daemon(...)
super.tap{ restart_thread }
end
prepend_features(Process.singleton_class)
end
```
----------------------------------------
Bug #18911: Process._fork hook point is not called when Process.daemon is used
https://bugs.ruby-lang.org/issues/18911#change-104713
* Author: ivoanjo (Ivo Anjo)
* Status: Closed
* Priority: Normal
* Assignee: akr (Akira Tanaka)
* ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-darwin20]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Hello there! I'm working at Datadog [on the `ddtrace` gem](https://github.com/DataDog/dd-trace-rb), and we need to hook into fork operations to make sure that our products work correctly/automatically even in environments that fork.
As part as #17795 a new `Process._fork` method was added to allow libraries and frameworks to easily hook into fork operations. I was investigating its use in `ddtrace` and noticed the following gap: the `Process.daemon` API internally makes use of `fork`, but the new hook point is not called for that API.
Testcase:
```ruby
puts RUBY_DESCRIPTION
module ForkHook
def _fork(*args)
puts " #{Process.pid} Before fork!"
res = super
puts " #{Process.pid} After fork!"
res
end
end
Process.singleton_class.prepend(ForkHook)
puts "#{Process.pid} Regular fork:"
fork { exit }
Process.wait
puts "#{Process.pid} Process.daemon:"
Process.daemon(nil, true)
puts "#{Process.pid} Finishing!"
```
Testcase output:
```
ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-darwin20]
48136 Regular fork: # <-- original process
48136 Before fork!
48136 After fork! # <-- original process
48137 After fork! # <-- child process
48136 Process.daemon: # <-- original process
48139 Finishing! # <-- forks and pid changes, but the hook isn't called
```
This was surprising to me since the advantage of this hook point would not not needing to hook into the many other places where `fork` can get called from.
Thanks a lot :)
--
https://bugs.ruby-lang.org/
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