posix: give checklink a fast path that cache the check file and is read only
util.checklink would create a symlink and remove it again. That would sometimes
happen multiple times. Write operations are relatively expensive and give disk
tear and noise for applications monitoring file system activity.
Instead of creating a symlink and deleting it again, just create it once and
leave it in .hg/cache/check-link . If the file exists, just verify that
os.islink reports true. We will assume that this check is as good as symlink
creation not failing.
Note: The symlink left in .hg/cache has to resolve to a file - otherwise 'make
dist' will fail ...
test-symlink-os-yes-fs-no.py does some monkey patching to simulate a platform
without symlink support. The slightly different testing method requires
additional monkeying.
#require bzr
$ . "$TESTDIR/bzr-definitions"
$ cat > treeset.py <<EOF
> import sys
> from bzrlib import workingtree
> wt = workingtree.WorkingTree.open('.')
>
> message, rootid = sys.argv[1:]
> wt.set_root_id('tree_root-%s' % rootid)
> wt.commit(message)
> EOF
change the id of the tree root
$ mkdir test-change-treeroot-id
$ cd test-change-treeroot-id
$ bzr init -q source
$ cd source
$ echo content > file
$ bzr add -q file
$ bzr commit -q -m 'Initial add'
$ python ../../treeset.py 'Changed root' new
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Initial add
0 Changed root
$ manifest source-hg tip
% manifest of tip
644 file
$ cd ..