context: only bother looking for broken dirstate for 20-byte changeid
If we fail to look up a changeid in changectx.__init__, we check if it
exactly matches any of the dirstate parents, and if it does, we print
a more specific message ("working directory has unknown parent '...'!"
instead of "unknown revision '...'"). The dirstate parents are always
20 bytes, so there's no need to check for a match when the given
changeid is not 20 bytes. (And now that all the other allowed forms of
changeid have been moved out of the constructor, there's no risk that
a changeid that did match a dirstate parent was actually a valid
bookmark.)
Differential Revision: https://phab.mercurial-scm.org/D3450
[workspace]
members = ["hgcli"]