Re: [PATCH 1/4] test-lib: add XSAN_OPTIONS, inherit [AL]SAN_OPTIONS

> On Fri, Feb 18, 2022 at 03:20:41PM -0800, Junio C Hamano wrote:
>> > +# Usage (using ":" as a delimiter):
>> > +#
>> > +#	prepend_var VAR : $1
>> > +prepend_var () {
>> > +	eval "$1=$3\${$1:+$2\$$1}"
>>
>> This one is correct; the above sample, when passed ":" and "VAR" to
>> $1 and $2, will specialize into the above example.
>
>> > +}
>> > +
>> > +# If [AL]SAN is in effect we want to abort so that we notice problems.
>> > +prepend_var XSAN_OPTIONS : abort_on_error=1
>>
>> XSAN_OPTIONS stands for "options that are common to all ?SAN", I
>> guess.
>
> I was also unclear on this. Looking around in the google/sanitizers
> repository, I don't see something called "XSAN_OPTIONS" mentioned
> anywhere (neither in documentation nor in the actual source code).
>
> Is this a convenience variable that we use to store options that are
> common to both ASAN_OPTIONS and LSAN_OPTIONS? If so, I am not sure the
> extra confusion is worth it, since it only contains abort_on_error=1.
>
> I guess it makes it (along with the prepend_var function introduced by
> this patch) possible for a caller to write XSAN_OPTIONS=... into their
> environment and then run a test script and have their settings feed into
> ASAN_OPTIONS and LSAN_OPTIONS. But I don't know that callers would find
> this super useful (or, at least not dramatically more convenient than
> setting both variables).
>
> I could be wrong, and I'm obviously biased towards my own usage of the
> ASAN/LSAN builds, but to me this patch might be clearer without the
> extra variable.