scmutil: create directories in a race-safe way during update
With the new parallel update code, it is possible for multiple
workers to try to create a hierarchy of directories at the same
time. This is hard to trigger in general, but most likely during
initial checkout.
To deal with these races, we introduce a new ensuredirs function
whose contract is to ensure that a directory hierarchy exists - it
will ignore a failure that implies that the desired directory already
exists.
$ cat >> $HGRCPATH <<EOF
> [extensions]
> convert=
> graphlog=
> EOF
$ hg init t
$ cd t
$ echo a >> a
$ hg ci -Am a0 -d '1 0'
adding a
$ hg branch brancha
marked working directory as branch brancha
(branches are permanent and global, did you want a bookmark?)
$ echo a >> a
$ hg ci -m a1 -d '2 0'
$ echo a >> a
$ hg ci -m a2 -d '3 0'
$ echo a >> a
$ hg ci -m a3 -d '4 0'
$ hg up -C 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg branch branchb
marked working directory as branch branchb
(branches are permanent and global, did you want a bookmark?)
$ echo b >> b
$ hg ci -Am b0 -d '6 0'
adding b
$ hg up -C brancha
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo a >> a
$ hg ci -m a4 -d '5 0'
$ echo a >> a
$ hg ci -m a5 -d '7 0'
$ echo a >> a
$ hg ci -m a6 -d '8 0'
$ hg up -C branchb
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo b >> b
$ hg ci -m b1 -d '9 0'
$ cd ..
convert with datesort
$ hg convert --datesort t t-datesort
initializing destination t-datesort repository
scanning source...
sorting...
converting...
8 a0
7 a1
6 a2
5 a3
4 a4
3 b0
2 a5
1 a6
0 b1
graph converted repo
$ hg -R t-datesort glog --template '{rev} "{desc}"\n'
o 8 "b1"
|
| o 7 "a6"
| |
| o 6 "a5"
| |
o | 5 "b0"
| |
| o 4 "a4"
| |
| o 3 "a3"
| |
| o 2 "a2"
| |
| o 1 "a1"
|/
o 0 "a0"
convert with datesort (default mode)
$ hg convert t t-sourcesort
initializing destination t-sourcesort repository
scanning source...
sorting...
converting...
8 a0
7 a1
6 a2
5 a3
4 b0
3 a4
2 a5
1 a6
0 b1
graph converted repo
$ hg -R t-sourcesort glog --template '{rev} "{desc}"\n'
o 8 "b1"
|
| o 7 "a6"
| |
| o 6 "a5"
| |
| o 5 "a4"
| |
o | 4 "b0"
| |
| o 3 "a3"
| |
| o 2 "a2"
| |
| o 1 "a1"
|/
o 0 "a0"