Is cp -al safe with git?

For one reason or another I would like to "clone" a local repo including the checked-out working tree with cp -al instead of cg-clone/git-clone, i.e. have all files hard-linked instead of copied.

Can the copies be worked on independently without interference (with the git tool set)?

One thing I noticed is that git-reset or probably git-checkout-index breaks links of files that need not be changed by the reset. Example:

# make 2 files, commit $ mkdir orig && cd orig $ git-init-db defaulting to local storage area $ echo foo > a && cp a b && git-add a b && git-commit -a -m 1 Committing initial tree 99b876dbe094cb7d3850f1abe12b4c5426bb63ea

# 2nd commit modifies only one file: $ echo bar > a && git-commit -a -m 2

# create the copy: $ cd .. $ cp -al orig copy $ cd copy

# working files are hard-linked: $ ls -l total 8 -rw-r--r-- 2 jsixt users 4 Nov 16 19:24 a -rw-r--r-- 2 jsixt users 4 Nov 16 19:23 b

# nuke a commit: $ git-reset --hard HEAD^ $ ls -l total 8 -rw-r--r-- 1 jsixt users 4 Nov 16 19:24 a -rw-r--r-- 1 jsixt users 4 Nov 16 19:24 b

I'd have expected that the hard-link of b remained and only a's link were broken. Does it mean that git-reset writes every single file also for large trees like the kernel? I cannot believe this. Can someone scratch the tomatoes off my eyes please?

-- Hannes