[ruby-core:77291] Re: RFC: optimizations opportunities in Hash#merge!

On 2016/09/14 01:57, Sylvain Joyeux wrote:

> I'm using Hash#merge and other hash-related update methods extensively, to
> the point where I spend a significant amount of time in #hash.
>
> So I went digging. It appears that Hash#merge is actually re-hashing its
> keys twice (once to compare the two hashes, and once to re-assign to the
> receiver).
>
> However, under the assumption that the block in Hash#merge! is not allowed
> to modify the key, no hashing should be needed at all.
>
> Or am I missing something ?

Based on the documentation, it doesn't look like changing the key is 
intended at all. But what about doing some code search to find examples 
of Hash#merge and friends and checking whether there are some key 
updates or not?


> I am ready to work on this, but I want to have a feel for whether such work
> would be welcome by the code devs before I invest time in it ... rather
> than have it thrown away as WONTFIX later.

I can't speak for others, but speed improvements should certainly be 
welcome. You may want to open a feature request on bugs.ruby-lang.org to 
submit your patch (or even before).

Regards,   Martin.

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