Serious Bug in v10.x.x : Function Map.values truncates elements

[Tunga37]

Version: v10.15.3 (10.x.x)
Platform: Linux 4.15.0-50-generic #54-Ubuntu SMP Mon May 6 18:46:08 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

This is the code that demonstrates the problem

const m = new Map();
m.set(1,'a');
m.set(2,'b');
m.set(3,'c');
m.set(4,'d');
m.set(5,'e');
m.set(6,'f');

//before delete [Map Iterator] { 'a', 'b', 'c', 'd', 'e', 'f' }
console.log('before delete',m.values());

m.delete(1);

//after delete [Map Iterator] { 'c', 'd', 'e', 'f' }
console.log('after delete',m.values());

//element 'b' has been truncated

It's probably more v8 problem than node itself (in node v12.x.x this is fixed) but the truth is ... this is very serious bug in node v10.x.x and I had to jump out of version 10.x.x because of this.

[addaleax]

I think this was fixed in 0afcb9a (aka v8/v8@88f8fe1). I’ll attempt a backport, that seems doable to me.

I don’t think this is a super-serious bug – to be clear, what is broken is the display of m.values() when using console.log or util.inspect(), not the actual functionality of m.values(), as far as I can tell.