bug#35660: guix weather runaway memory consumption

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

retitle 35660 Implement cycle detection with proper reporting
thanks

swedebugia <swedebugia@riseup.net> writes:

> On 2019-05-14 22:52, Ludovic Courtès wrote:
>> Hi Danny,
>> Danny Milosavljevic <dannym@scratchpost.org> skribis:
>> 
>>> The failure mode here is very very bad.  Guix will consume all available
>>> memory and then start on the swap, at which point the computer will
>>> become unresponsive to any input and the user can't save any open
>>> documents and has to kill the power to the computer.
>> I agree that the failure mode is terrible.  It’s very likely a cycle
>> in
>> the package graph, given the symptoms you describe.  So ‘guix build
>> OFFENDING-PACKAGE’ would probably give you the same result.
>> Chris Baines proposed a patch a while back to detect and report
>> cycles,
>> but we never got around to polishing and integrating it.  That would
>> probably help a lot in these cases.
>> We can open a new bug for that (if there’s not already one), but I
>> think
>> it should be framed in terms of cycle detection in the package graph and
>> error reporting.
>
> +1

This would indeed be very useful.  I'm retitling this bug so that it is
more actionable.  Could someone link to the patch Chris Baines had
written going in this direction?

Thanks,

Maxim