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 hardlink
$ echo "[extensions]" >> $HGRCPATH
$ echo "relink=" >> $HGRCPATH
$ fix_path() {
> tr '\\' /
> }
$ cat > arelinked.py <<EOF
> import sys, os
> from mercurial import util
> path1, path2 = sys.argv[1:3]
> if util.samefile(path1, path2):
> print '%s == %s' % (path1, path2)
> else:
> print '%s != %s' % (path1, path2)
> EOF
create source repository
$ hg init repo
$ cd repo
$ echo a > a
$ echo b > b
$ hg ci -Am addfile
adding a
adding b
$ cat "$TESTDIR/binfile.bin" >> a
$ cat "$TESTDIR/binfile.bin" >> b
$ hg ci -Am changefiles
make another commit to create files larger than 1 KB to test
formatting of final byte count
$ cat "$TESTDIR/binfile.bin" >> a
$ cat "$TESTDIR/binfile.bin" >> b
$ hg ci -m anotherchange
don't sit forever trying to double-lock the source repo
$ hg relink .
relinking $TESTTMP/repo/.hg/store to $TESTTMP/repo/.hg/store (glob)
there is nothing to relink
Test files are read in binary mode
$ $PYTHON -c "file('.hg/store/data/dummy.i', 'wb').write('a\r\nb\n')"
$ cd ..
clone and pull to break links
$ hg clone --pull -r0 repo clone
adding changesets
adding manifests
adding file changes
added 1 changesets with 2 changes to 2 files
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd clone
$ hg pull -q
$ echo b >> b
$ hg ci -m changeb
created new head
$ $PYTHON -c "file('.hg/store/data/dummy.i', 'wb').write('a\nb\r\n')"
relink
$ hg relink --debug --config progress.debug=true | fix_path
relinking $TESTTMP/repo/.hg/store to $TESTTMP/clone/.hg/store
tip has 2 files, estimated total number of files: 3
collecting: 00changelog.i 1/3 files (33.33%)
collecting: 00manifest.i 2/3 files (66.67%)
collecting: a.i 3/3 files (100.00%)
collecting: b.i 4/3 files (133.33%)
collecting: dummy.i 5/3 files (166.67%)
collected 5 candidate storage files
not linkable: 00changelog.i
not linkable: 00manifest.i
pruning: data/a.i 3/5 files (60.00%)
not linkable: data/b.i
pruning: data/dummy.i 5/5 files (100.00%)
pruned down to 2 probably relinkable files
relinking: data/a.i 1/2 files (50.00%)
not linkable: data/dummy.i
relinked 1 files (1.36 KB reclaimed)
$ cd ..
check hardlinks
$ python arelinked.py repo/.hg/store/data/a.i clone/.hg/store/data/a.i
repo/.hg/store/data/a.i == clone/.hg/store/data/a.i
$ python arelinked.py repo/.hg/store/data/b.i clone/.hg/store/data/b.i
repo/.hg/store/data/b.i != clone/.hg/store/data/b.i