Issue #10231 has been reported by Charles Nutter.

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Bug #10231: Process.detach(pid) defines new singleton classes every call
https://bugs.ruby-lang.org/issues/10231

* Author: Charles Nutter
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: Any version with Process.detach
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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The logic for Process.detach(pid) adds a singleton "pid" method to the thread it returns for every call. This is bad for method caches (MRI still flushes them all for this, I believe) and memory churn (singleton classes are not small).

The offending line of code is here: https://github.com/ruby/ruby/blob/trunk/process.c#L1041

I would suggest that Process.detach should return a subclass of Thread that has the pid method defined ahead of time.

It also stores the value in thread local storage, rather than as an instance variable. I'm not sure why.



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