[Aptitude-devel] Bug#824441: Bug#824441: Bug#824441: aptitude segfaults when marking texlive-generic-extra as auto-installed

[David Kalnischkies]

Hi,

(disclaimer: apt, not aptitude, maintainer talking)

On Fri, May 20, 2016 at 09:54:23AM +1000, James Tocknell wrote:
> 0x00007ffff7b3feed in debVersioningSystem::CheckDep(char const*, int, char
> const*) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.5.0
> #0  0x00007ffff7b3feed in debVersioningSystem::CheckDep(char const*, int,
> char const*) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.5.0
> #1  0x00005555557767c1 in infer_reason (pkg=..., reasons=std::set with 1
> elements = {...}) at ../../../../src/generic/apt/infer_reason.cc:178

[It is a bit confusing that the code of frame #1 is actually calling
IsSatisfied(), but it is just a wrapper around CheckDep() so lets just
ignore that for the moment]

10f0cf4a04b2526e9dea65facde865d993396417 adds this code, which passes
the candidate version to IsSatisfied – but not all packages have
a candidate! So that code should be adapted to test first if the package
has a candidate and only if so check if the candidate satisfies the
dependency.


Now, we could ask why IsSatisfied requires a valid version and the
answer is: nobody (aka me) thought anybody would pass it an invalid
version as the soul reason for the one-line IsSatisfied is to hide the
call to CheckDep behind a slightly nicer interface (1 vs 3 parameters)
and all existing calls in apt passed only valid versions in…

I am not sure it is a good idea to add checks to that method as its in
various hot paths for apt & it has the potential of hiding bugs (at the
expense of opening some like here). Either way, that needs more thought
than I can shell out at the moment & adapting the call site should be
easy.


Best regards

David Kalnischkies
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