Fix Array keep_if, delete_if, reject!, select!

[elia]

Match CRuby behavior when exceptions are raised in the block and about
when the array is updated.

Fixes #2067

[iliabylich]

MRI aborts iteration once the error has been thrown:

[1,2,3].keep_if { |i| p i; raise 'a' }
1
# ...backtrace
RuntimeError (a)

So I guess this check-and-throw should be somewhere above (same for other methods)

[iliabylich]

Also I guess it may catch and re-throw Opal.breaker and Opal.returner and thus, potentially exit the outer method call

[elia]

From what I saw they're already managed by the compiler.

[iliabylich]

compiler manages only what is written in Ruby (but catch/re-throw here is in JS). maybe I'm wrong, but does it handle break and return inside keep_if? 👍 if so, but I'm afraid it swallows the initial throw Opal.returner and re-raises it once the loop is done (MRI most probably does a hard return that aborts the loop)

Also, I'm not sure if it's actually that important. I've never seen such code 😄

[elia]

just out of curiosity, here's what I got:

opal:elia/fix-delete-if-keep-if ⤑ bin/opal -e'def a;4.times{|n| [1,2,3].delete_if { |i| p i; return }; p n => n};end; a'          ~/C/opal
1
opal:elia/fix-delete-if-keep-if ⤑ ruby -e'def a;4.times{|n| [1,2,3].delete_if { |i| p i; return }; p n => n};end; a'              ~/C/opal
1
opal:elia/fix-delete-if-keep-if ⤑                                                                                                 ~/C/opal

[elia]

Thanks for the review, I've updated the code to stop calling the block and behave just like MRI.

[iliabylich]

👍