localrepository.status: only acquire wlock if actually needed.
This speeds up the common case of not needing to update the dirstate,
and avoids the need to reload and parse the dirstate "just in case".
#!/bin/sh
hg --debug init
echo this is a1 > a
hg add a
hg commit -m0 -d "1000000 0"
echo this is b1 > b
hg add b
hg commit -m1 -d "1000000 0"
hg manifest --debug 1
echo this is c1 > c
hg rawcommit -p 1 -d "1000000 0" -m2 c
hg manifest --debug 2
hg -v parents
rm b
hg rawcommit -p 2 -d "1000000 0" -m3 b
hg manifest --debug 3
hg -v parents
echo this is a22 > a
hg rawcommit -p 3 -d "1000000 0" -m4 a
hg manifest --debug 4
hg -v parents
echo this is c22 > c
hg rawcommit -p 1 -d "1000000 0" -m5 c
hg manifest --debug 5
hg -v parents
# merge, but no files changed
hg rawcommit -p 4 -p 5 -d "1000000 0" -m6
hg manifest --debug 6
hg -v parents
# no changes what-so-ever
hg rawcommit -p 6 -d "1000000 0" -m7
hg manifest --debug 7
hg -v parents