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.
http://mercurial.selenic.com/bts/issue322
File replaced with directory:
$ hg init a
$ cd a
$ echo a > a
$ hg commit -Ama
adding a
$ rm a
$ mkdir a
$ echo a > a/a
Should fail - would corrupt dirstate:
$ hg add a/a
abort: file 'a' in dirstate clashes with 'a/a'
[255]
$ cd ..
Directory replaced with file:
$ hg init c
$ cd c
$ mkdir a
$ echo a > a/a
$ hg commit -Ama
adding a/a
$ rm -r a
$ echo a > a
Should fail - would corrupt dirstate:
$ hg add a
abort: directory 'a' already in dirstate
[255]
$ cd ..
Directory replaced with file:
$ hg init d
$ cd d
$ mkdir b
$ mkdir b/c
$ echo a > b/c/d
$ hg commit -Ama
adding b/c/d
$ rm -r b
$ echo a > b
Should fail - would corrupt dirstate:
$ hg add b
abort: directory 'b' already in dirstate
[255]