tests: fix timer scaling in wait-on-file When using the default test timeouts, wait-on-file would not wait for $n seconds, but $n/100 seconds. This resulted in easy timeouts on even moderately busy fast machines. Fix the scaling to apply in all cases. Adjust the stepping slightly to be nicer to systems with the historic 100Hz time base to ensure that the scheduler actually switches to a different process and gives them time to work. Differential Revision: https://phab.mercurial-scm.org/D8505

manifest-cache: ignore IOError while writing If the wcache directory is non writable for some reason (eg: belong to root). Trying to write to it currently crash Mercurial. Instead we ignore the error and skip writing that cache. We should probably improve the user experience of multiple users interacting with the same repository. However this is not an adventure for stable. Differential Revision: https://phab.mercurial-scm.org/D8512

copy: give better error message when no source paths found with --at-rev The new error message matches what we show when marking copies in the working copy. Differential Revision: https://phab.mercurial-scm.org/D8496