fetch: fix and document exit codes (
issue2356)
filectx: use ctx.size comparisons to speed up ctx.cmp
Comparing sizes is cheaper than comparing file contents, as it does not
involve reading the file on disk or from the filelog.
It is however not always possible: some extensions, or encode filters,
change data when extracting it to the working directory.
wireproto: introduce pusherr() to deal with "unsynced changes" error
The behaviour between http and ssh still differ:
- the "unsynced changes" is seen as a remote output in the http cases
- but it is correctly seen as a push error for ssh