Bug#1061049: libsuitesparse-dev: libsuitesparse-dev 7.4.0 has an ABI break in libcholmod5 without bumping to "libcholmod6"

[Dima Kogan]

Package: libsuitesparse-dev
Version: 1:7.3.1+dfsg-2
Severity: serious
X-Debbugs-Cc: none, Dima Kogan <dko...@debian.org>

Hi. I'm chasing down

  http://bugs.debian.org/1060986

The problem is that mrcal uses libdogleg, which contains

  typedef struct
  {
    cholmod_common  common;
    ....
  } dogleg_solverContext_t;

The existing "libdogleg2" package was built against libsuitesparse-dev
7.3, so it must be linked with packages that use that ABI. But in
suitesparse 7.4 the cholmod_common structure has a new member at the
end:

    FILE *blas_dump ;  // only used if CHOLMOD is compiled with -DBLAS_DUMP

This is in CHOLMOD/Include/cholmod.h

This extra member changes sizeof(cholmod_common), which changes the ABI,
causing the crash. One way to fix this is to bump the SONAME of
libcholmod.

Thanks.