[ruby-core:41894] [Backport93 - Backport #5835] Please Backport r34202 and r34204 (rexml BaseParser uses instance_eval unnecessarily on listener add)

Issue #5835 has been updated by Ayumu AIZAWA.

File backport_5835.patch added
% Done changed from 100 to 0


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Backport #5835: Please Backport r34202 and r34204 (rexml BaseParser uses instance_eval unnecessarily on listener add)
https://bugs.ruby-lang.org/issues/5835

Author: Charles Nutter
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


In add_listener in REXML::BaseParser, there's code to instance eval and replace the old "pull" method with a new one that calls all listeners. I assume this was done to avoid the cost of calling .each on the listeners when there's none registered, but when the list is empty this call is nearly a no-op anyway. The singletonizing effect of instance_eval and the redefinition of #pull, on the other hand, cause a cache flush throughout the system.

I have created a patch that removes the instance_eval, initializes the listeners array unconditionally, and does the event #each unconditionally. It passes all tests, and should perform better because it's not damaging the cache.

https://gist.github.com/1420383

This can be safely backported to any Ruby version and has no visible behavior change.


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