Re: git-checkout and SUBDIRECTORY_OK='Yes'

[Junio C Hamano <junkio@cox.net>]

Junio C Hamano <junkio@cox.net> writes:

> Jon Nelson <jnelson-git@jamponi.net> writes:
>
>> Is it safe to set SUBDIRECTORY_OK='Yes' in git-checkout.sh?

> This patch *might* work, or it may not...

I've done some tests and it seems to work (it is in the
proposed updates branch).

In git.git working tree, here is what happens:

	$ git checkout pu			;# start from pu
        $ cd Documentation
        $ echo >>git-daemon.txt			;# smudge
        $ git checkout -- git-daemon.txt	;# restore
	$ git diff -r --name-status		;# no change
        $ git checkout master git-daemon.txt	;# pick from tree
	$ git diff master -r --name-status	;# (1)
	$ git diff -r --name-status		;# (2)
	$ git diff pu -r --name-status          ;# (3)
        M	Documentation/git-daemon.txt

    (1) does not show any because it did take the file out of master
        branch, and git-daemon.txt is the only file different under
        Documentation/ between master and pu.

    (2) does not show any because "checkout master git-daemon.txt"
        updated the path both in index and working tree.

    (3) shows the path indeed is different between master and pu.

The change relies on ls-tree showing full paths regardless of
where it gets started (because the output is fed to --index-info
form of git-update-index).  If we are going to take the "ls-tree
prefix truncation" patch from Linus, either we also need to
update "git-update-index --index-info" to match this.