checknlink: return False if .hgtmp file preexists (issue2517)
If os_link fails on Windows, errno is always errno.EINVAL,
so we can't really say if the testlink could not be created
because (a) the FS doesn't support hardlinks or (b) there
is a leaked .hgtmp file lying around from a previous crashed
run.
So let's err on the safe side, keep the code simple and assume
we can't detect hardlinks in both cases.
$ hg init test
$ cd test
$ cat > .hg/hgrc <<EOF
> [server]
> validate=1
> EOF
$ echo alpha > alpha
$ echo beta > beta
$ hg addr
adding alpha
adding beta
$ hg ci -m 1
$ cd ..
$ hg clone test test-clone
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd test-clone
$ cp .hg/store/data/beta.i tmp
$ echo blah >> beta
$ hg ci -m '2 (corrupt)'
$ mv tmp .hg/store/data/beta.i
Expected to fail:
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
beta@1: dddc47b3ba30 in manifests not found
2 files, 2 changesets, 2 total revisions
1 integrity errors encountered!
(first damaged changeset appears to be 1)
[1]
Expected to fail:
$ hg push
pushing to $TESTTMP/test
searching for changes
adding changesets
adding manifests
adding file changes
transaction abort!
rollback completed
abort: missing file data for beta:dddc47b3ba30e54484720ce0f4f768a0f4b6efb9 - run hg verify
[255]