manifest: convert a recursive function to iterative one using stacks I am debugging a memory issue from yesterday where `hg update` goes upto taking 22GB of memory on our internal treemanifest repository. This is an interesting function and I saw memory consumption increasing while this function was running. It's sometimes hard to understand a recursive function and also the profile won't show you actual operations which took time, rather it will show you the function again and again in profile. I am yet to notice any memory consumption decrease with this patch, but I believe this will help like in making this a generator. Differential Revision: https://phab.mercurial-scm.org/D5413