chgserver: update the umask cache before each run
posix.py uses a global variable to store the umask value resulting in caching of
it when using chg. We need to update it before each command run as the umask can
change between commands.
This fixes test-inherit-mode.t with chg.
$ hg init
$ mkdir d1 d1/d11 d2
$ echo d1/a > d1/a
$ echo d1/ba > d1/ba
$ echo d1/a1 > d1/d11/a1
$ echo d1/b > d1/b
$ echo d2/b > d2/b
$ hg add d1/a d1/b d1/ba d1/d11/a1 d2/b
$ hg commit -m "intial"
Test single file
# One recoded copy, one copy to record after commit
$ hg cp d1/b d1/c
$ cp d1/b d1/d
$ hg add d1/d
$ hg ci -m 'copy d1/b to d1/c and d1/d'
$ hg st -C --change .
A d1/c
d1/b
A d1/d
# Errors out without --after for now
$ hg cp --at-rev . d1/b d1/d
abort: --at-rev requires --after
[255]
# Errors out with non-existent destination
$ hg cp -A --at-rev . d1/b d1/non-existent
abort: d1/non-existent: copy destination does not exist in 8a9d70fa20c9
[255]
# Successful invocation
$ hg cp -A --at-rev . d1/b d1/d
saved backup bundle to $TESTTMP/.hg/strip-backup/8a9d70fa20c9-973ae357-copy.hg
# New copy is recorded, and previously recorded copy is also still there
$ hg st -C --change .
A d1/c
d1/b
A d1/d
d1/b
Test using directory as destination
$ hg co 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ cp -R d1 d3
$ hg add d3
adding d3/a
adding d3/b
adding d3/ba
adding d3/d11/a1
$ hg ci -m 'copy d1/ to d3/'
created new head
$ hg cp -A --at-rev . d1 d3
abort: d3: --at-rev does not support a directory as destination
[255]