Re: [PATCH 2/2] test-lib.sh: Dynamic test for the prerequisite SANITY

[Junio C Hamano <gitster@pobox.com>]

On Wed, Jan 28, 2015 at 12:28 AM, Torsten Bögershausen <tboegi@web.de> wrote:
> On 27.01.15 23:20, Junio C Hamano wrote:
>
>> How about extending it like this (not tested)?
> Thanks, this looks good: the test is more extensive,
> I can test this next week.
>
>>
>> -- >8 --
>> From: Torsten Bögershausen <tboegi@web.de>
>> Date: Tue, 27 Jan 2015 16:39:01 +0100
>> Subject: [PATCH] test-lib.sh: set prerequisite SANITY by testing what we really need
>>
>> What we wanted out of the SANITY precondition is that the filesystem
>> behaves sensibly with permission bits settings.
>>
>>  - You should not be able to remove a file in a read-only directory,
>>
>>  - You should not be able to tell if a file in a directory exists if
>>    the directory lacks read or execute permission bits.

Forgot one thing. I do not offhand know if tests that needs SANITY
depends on this, but we may also want to check for this:

 - You should not be able to write to a file that is marked as read-only.

by adding something like

  >sanitytest && chmod -w sanitytest && ! echo boo >sanitytest && !
test -s sanitytest"

in the mix.

>>
>> We used to cheat by approximating that condition with "is the /
>> writable?" test and/or "are we running as root?" test.  Neither test
>> is sufficient or appropriate in more exotic environments like
>> Cygwin.
> How about going this direction:
>
> We used to cheat by approximating that condition with "is the /
> writable?" test and/or "are we running as root?" test. Neither test
> is sufficient or appropriate, especially in environments like
> Cygwin, Mingw or Mac OS X.

OK, but MacOS X does not have SANITY problem; "is the / writable?" test
was misdetecting and declaring a system with SANITY does not have one.

Perhaps roll Cygwin and Mingw into a single Windows category? I dunno.