Backport #5835: Please Backport r34202 and r34204 (rexml BaseParser uses instance_eval unnecessarily on listener add)

• Status: Closed
• Assignee: -

[headius (Charles Nutter)]

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.

[ayumin (Ayumu AIZAWA)]

• Subject changed from rexml BaseParser uses instance_eval unnecessarily on listener add to Please Backport r34202 (rexml BaseParser uses instance_eval unnecessarily on listener add)

[kou (Kouhei Sutou)]

• Subject changed from Please Backport r34202 (rexml BaseParser uses instance_eval unnecessarily on listener add) to Please Backport r34202 and r34204 (rexml BaseParser uses instance_eval unnecessarily on listener add)

[ayumin (Ayumu AIZAWA)]

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

[ayumin (Ayumu AIZAWA)]

Merged by r3224 r3223

[ayumin (Ayumu AIZAWA)]

• Status changed from Open to Closed