[PATCHv2] Fix backwards-incompatible handling of core.sharedRepository

The 06cbe8550324e0fd2290839bf3b9a92aa53b70ab core.sharedRepository handling extension broke backwards compatibility; before, shared=1 meant that Git merely ensured the repository is group-writable, not that it's _only_ group-writable, which is the current behaviour. Thus, with umask 002, Git creates repository with /rw.rw.--./, this patch fixes it back to /rw.rw.r-./.

Maybe it makes sense to provide the current semantics in some way too, but that cannot be done at the expense of ditching backwards compatibility; this bug has just wasted me two hours and broke repo.or.cz pushing for several hours.

Cc: Heikki Orsila <heikki.orsila@iki.fi>
Signed-off-by: Petr Baudis <pasky@rover.dkm.cz>
---

  The patch description is clarified and a test is added to t1301.

 path.c                 |    2 +-
 t/t1301-shared-repo.sh |   19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletions(-)

The 06cbe8550324e0fd2290839bf3b9a92aa53b70ab core.sharedRepository handling extension broke backwards compatibility; before, shared=1 meant that Git merely ensured the repository is group-writable, not that it's _only_ group-writable, which is the current behaviour. Thus, with umask 002, Git creates repository with /rw.rw.--./, this patch fixes it back to /rw.rw.r-./.

Maybe it makes sense to provide the current semantics in some way too, but that cannot be done at the expense of ditching backwards compatibility; this bug has just wasted me two hours and broke repo.or.cz pushing for several hours.

Cc: Heikki Orsila <heikki.orsila@iki.fi>
Signed-off-by: Petr Baudis <pasky@rover.dkm.cz>
---

  Oops, this testcase wouldn't really remove its test subrepository
after itself properly, though the testsuite would still pass; of course
this bug slipped through all the previous visual inspections of mine.

  Sorry for the continuous noise. :-)

 path.c                 |    2 +-
 t/t1301-shared-repo.sh |   20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletions(-)

Petr Baudis <pasky@suse.cz> writes:

Is it just me who finds the above unreadable blob of black ink?

	06cbe85 (Make core.sharedRepository more generic, 2008-04-16)
	broke the traditional setting core.sharedRepository to true,
        which was to make the repository group writable.

	The call to adjust_shared_perm() should only loosen the
	permission.  If the user has umask 002 (or 022) that allow others
	to read, the resulting files should be made readable and writable
	by group, without restricting the readability by others.

I do not think this gripe after the semicolon belongs before the three-dash lines.

Hmm, I am very puzzled.

I am afraid I have to ask you for another round. I applied only your update to t/t1301 without the change to path.c, and the test passes, which means either (1) the test is incorrect and does not exposing the breakage, or (2) the breakage is not real and existing code is correct.

06cbe85 (Make core.sharedRepository more generic, 2008-04-16) broke the traditional setting of core.sharedRepository to true, which was to make the repository group writable: with umask 022, it would clear the permission bits for 'other'. (umask 002 did not exhibit this behaviour since pre-chmod() check in adjust_shared_perm() fails in that case.)

The call to adjust_shared_perm() should only loosen the permission. If the user has umask like 022 or 002 that allow others to read, the resulting files should be made readable and writable by group, without restricting the readability by others.

This patch fixes the adjust_shared_perm() mode tweak based on Junio's suggestion and adds the appropriate tests to t/t1301-shared-repo.sh.

Cc: Heikki Orsila <heikki.orsila@iki.fi>
Signed-off-by: Petr Baudis <pasky@suse.cz>
---

  Fourth iteration. The problem is in fact triggered with umask 022,
not 002; fixed the description and extended the testsuite appropriately.
Improved patch description as well as the adjust_shared_perm() fix based
on Junio's suggestions here and on #git, so by now it's more of his
patch than mine. :-)

 path.c                 |    2 +-
 t/t1301-shared-repo.sh |   22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletions(-)