Problems with DEFSYSTEM-DEPENDS-ON

[Robert Goldman]

On 9 Apr 2018, at 11:17, Attila Lendvai wrote:

>> A cheesy fix would simply be to wrap it in IGNORE-ERRORS. But it 
>> might cause
>> errors in its present form.
>
>
> i've learned, painfully, that indiscriminate ignore-errors will almost
> always bite you back (in the form of wasted debugging time), no matter
> how innocent they look.
>
>
>> This really is more a QL issue than an ASDF one (although it 
>> illustrates an
>> issue with wrapping errors, IMO).
>
>
> while this is true, the implementation of QL requires a reliable way
> to hook into the internal state of various versions of ASDF (namely,
> into the situation when ASDF is looking for a system, and not finding
> it will lead to an error without QL intervention). if i understand it
> correctly, this is the crux of this issue.

Sure, and I am happy to try to support this, but not to the extent of 
recovering a copy of ASDF 2.x and trying to run it.

The problem is that I don't know when the missing component condition 
was added to ASDF, and doing this right would involve checking the 
enclosed condition to see if it's a missing component error.  I know how 
to do that for a modern ASDF, but I don't know how to handle ASDFs that 
are too old to have this condition class.  And I don't fee like it's my 
job to think about that: I think it's perverse to continue trying to use 
ASDF 2.

Best,
r