dirstate: implement __len__ on dirstatemap (
issue5695)
Differential Revision: https://phab.mercurial-scm.org/D884
obsmarker: crash more helpfully when metadata fields are >255bytes (
issue5681)
Various mutators fail when attempting to write obsmarkers with
metadata fields longer than 255 bytes, since the length of
mwetadata fields is stored in u8s. This change raises a more
helpful error in such circumstances.
Differential Revision: https://phab.mercurial-scm.org/D865