Re: Unexpected pass for t6120-describe.sh on cygwin

From: Michael J Gruber <git@grubix.eu>
Date: Sep 13, 2017, 09:08 UTC
Message-ID: <52f990d5-cdac-b516-269c-acbb68897e6e@grubix.eu>
In-Reply-To: <alpine.DEB.2.21.1.1709121538360.4132@virtualbox>

Johannes Schindelin venit, vidit, dixit 12.09.2017 15:39:

Show 23 quoted lines

> Hi Ramsay,
> 
> On Sat, 9 Sep 2017, Ramsay Jones wrote:
> 
>> I ran the test-suite on the 'pu' branch last night (simply because that
>> was what I had built at the time!), which resulted in a PASS, but t6120
>> was showing a 'TODO passed' for #52.
>>
>> This is a test introduced by Michael's 'mg/name-rev-tests-with-short-stack'
>> branch, which uses 'ulimit -s' to try and force a stack overflow.
>> Unfortunately, 'ulimit -s' seems to have no effect on cygwin. I created
>> a test program (see below) to eat up the stack and tried running it with
>> various ulimit values (128, 12, 8), but it always seg-faulted at the
>> same stack-frame. (after using approx 2MB stack space).
>>
>> So, it looks like all ULIMIT_STACK_SIZE tests need to be disabled
>> on cygwin. I also wonder about the ULIMIT_FILE_DESCRIPTORS tests, but
>> haven't looked into it.
>>
>> Given that 'ulimit' is a bash built-in, this may also be a problem on
>> MinGW and Git-For-Windows, but I can't test on those platforms.
> 
> It is.

Thanks.

I just dug something up from an old cygwin list post. Could you please try and report on the following (cygwin, MinGW):

ulimit -s ulimit -s 4096 # anything lower than the value from above ulimit -s bash -c "ulimit -s"

My suspicion from that post is that ulimit affects the sub shell only -
if yes, running a test inside the sub shell to confirm whether the
setting is in effect would be great, of course. /usr/bin/echo $(seq
100000) or such does the job on Linux (with stack limit 128), but I
don't know whether this is portably reliable.

If ulimit on these platforms has no effect but does not lie about the value either it's a simple prerequisite test (test ulimit present, if yes set and get and compare the stack size values).

Michael