make appendfile simpler so it does not break with revlogng on windows.
it used to cache open files. this made revlogng break because it wants
to rename files when splitting .i into .i/.d, but cannot rename or unlink
open files on windows.
new code is bit slower, but safe on linux and windows. proper fix for
too many open/close of changelog/manifest belongs in different place.
can get 10% speed improvement back.
#!/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 1
echo this is c1 > c
hg rawcommit -p 1 -d "1000000 0" -m2 c
hg manifest 2
hg parents
rm b
hg rawcommit -p 2 -d "1000000 0" -m3 b
hg manifest 3
hg parents
echo this is a22 > a
hg rawcommit -p 3 -d "1000000 0" -m4 a
hg manifest 4
hg parents
echo this is c22 > c
hg rawcommit -p 1 -d "1000000 0" -m5 c
hg manifest 5
hg parents
# merge, but no files changed
hg rawcommit -p 4 -p 5 -d "1000000 0" -m6
hg manifest 6
hg parents
# no changes what-so-ever
hg rawcommit -p 6 -d "1000000 0" -m7
hg manifest 7
hg parents