extend network protocol to stop clients from locking servers
now all repositories have capabilities slot, tuple with list of names.
if 'unbundle' capability present, repo supports push where client does
not need to lock server. repository classes that have unbundle capability
also have unbundle method.
implemented for ssh now, will be base for push over http.
unbundle protocol acts this way. server tells client what heads it
has during normal negotiate step. client starts unbundle by repeat
server's heads back to it. if server has new heads, abort immediately.
otherwise, transfer changes to server. once data transferred, server
locks and checks heads again. if heads same, changes can be added.
else someone else added heads, and server aborts.
if client wants to force server to add heads, sends special heads list of
'force'.
#!/bin/sh
hg init
touch a
hg add a
hg commit -m "Added a" -d "1000000 0"
touch main
hg add main
hg commit -m "Added main" -d "1000000 0"
hg checkout 0
echo Main should be gone
ls
touch side1
hg add side1
hg commit -m "Added side1" -d "1000000 0"
touch side2
hg add side2
hg commit -m "Added side2" -d "1000000 0"
hg log
echo Should have two heads, side2 and main
hg heads
echo Should show "a side1 side2"
ls
hg update --debug -C 1
echo Should only show "a main"
ls