tests: in helpers-testrepo.sh switch from shell aliases to functions The reason is that I want this script to work in non-interactive shells too. (will be used in the next commit)

rust: fix the deprecation warning in NaiveDateTime::from_timestamp This warning appears between chrono 0.4.34 and 0.4.38, so isn't affecting the current lock file, but it would come when we upgraded the version.

run-tests: ensure that --no-rust do not use rust Since having a valid value in HGWITHRUSTEXT is enough to trigger the use of rust, we need to unset it before install to be sure.

revlogutils: teach issue6528 filtering about grandparents During dynamic filtering, we should assume that the current repository is correct. Therefore the parents of the delta base can tell us if that parent has metadata without having to build the whole text.

revlogutils: remember known metadata parents for issue6528 In the cases where the parent revs tell us for sure that the parent has metadata, remember this fact to avoid content recomputations later.

revlogutils: for issue6528 fix, pre-cache nullrev as metadata-free

revlogutils: for issue6528 fix, cache results for null changes