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]
> graphlog=
> histedit=
> EOF
$ initrepos ()
> {
> hg init r
> cd r
> for x in a b c ; do
> echo $x > $x
> hg add $x
> hg ci -m $x
> done
> cd ..
> hg clone r r2 | grep -v updating
> cd r2
> for x in d e f ; do
> echo $x > $x
> hg add $x
> hg ci -m $x
> done
> cd ..
> hg init r3
> cd r3
> for x in g h i ; do
> echo $x > $x
> hg add $x
> hg ci -m $x
> done
> cd ..
> }
$ initrepos
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
show the edit commands offered by outgoing
$ cd r2
$ HGEDITOR=cat hg histedit --outgoing ../r | grep -v comparing | grep -v searching
pick 055a42cdd887 3 d
pick e860deea161a 4 e
pick 652413bf663e 5 f
# Edit history between 055a42cdd887 and 652413bf663e
#
# Commands:
# p, pick = use commit
# e, edit = use commit, but stop for amending
# f, fold = use commit, but fold into previous commit (combines N and N-1)
# d, drop = remove commit from history
# m, mess = edit message without changing commit content
#
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..
show the error from unrelated repos
$ cd r3
$ HGEDITOR=cat hg histedit --outgoing ../r | grep -v comparing | grep -v searching
abort: repository is unrelated
[1]
$ cd ..
show the error from unrelated repos
$ cd r3
$ HGEDITOR=cat hg histedit --force --outgoing ../r
comparing with ../r
searching for changes
warning: repository is unrelated
pick 2a4042b45417 0 g
pick 68c46b4927ce 1 h
pick 51281e65ba79 2 i
# Edit history between 2a4042b45417 and 51281e65ba79
#
# Commands:
# p, pick = use commit
# e, edit = use commit, but stop for amending
# f, fold = use commit, but fold into previous commit (combines N and N-1)
# d, drop = remove commit from history
# m, mess = edit message without changing commit content
#
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd ..