HashMap does not remove a key

It seems like the problems with TrieMap implementation persist. I just observed a case where HashMap would not remove a key with both Remove. I temporarily fixe dit with toHashMap(hashMap.AsEnumerable()). I’ll try to replicate it and update the issue.

[iamim]

Everything seems to work fine. Thanks! Closing the issue.

[louthy]

Ok, I found the core issue. It’s fixed in 3.3.16 if you want to run it through your tests.

Essentially as the trie grows the mask for each entry has a different value; 2085595311 has a mask of 32768 at level 1, but when there’s multiple entries on level one with the same mask then a new level is created and the two items move to that level. 2085595311 then has a mask of 32.

When removing one of the items, so there’s only one left, there was a check for this so that level 2 gets removed and the one item that’s left moves back to level 1. What wasn’t happening was a recalculation of the mask from 32 back to 32768. Which meant subsequent checks to see if the item exists would fail and so 2085595311 could be added again.

Because of this I’ve been able to remove my other temporary fixes, because I suspect this is the only issue.

The joys of highly optimised imperative programming /sarcasm