changegroup: use any node, not min(), in treemanifest's generatemanifests This is fixing quadratic behavior, which is probably not noticeable in the common case, but if a very large directory gets added here, it can get pretty bad. This was noticed because we had some pushes that spent >25s in changegroup generation calling min() here, according to profiling. The original reasoning for min() being used in 829d369fc5a8 was that, at that point in the series, we were adding almost everything to tmfnodes during the first iteration through the loop , so we needed to avoid sending child directories before parents. Later changes made it so that the child directories were added only when we visited the parent directory (not all of them on the first iteration), so this is no longer necessary - there won't be any child directories in tmfnodes before the parents have been sent. This does mean that the manifests are now exchanged unordered, whereas previously we would essentially do [a, b, b/c, b/c/d, e], we now can send a, b, and e in any order; b/c must still follow b, and b/c/d must still follow b/c. Differential Revision: https://phab.mercurial-scm.org/D1351