[petsc-dev] petsc/master: unable to link in C++ with last night PETSC_WITH_EXTERNAL_LIB variable changes

[Jed Brown]

Matthew Knepley <knepley at gmail.com> writes:

>> Note that PETSc's own dependency management is messy because someone in
>> the early days of BuildSystem thought that concatenating strings was
>> sufficient, instead of maintaining a structured dependency graph to be
>> topologically sorted at the final stage (pkg-config does this).
>>
>
> Of course, we do have a structured dependency graph. Where is it not being
> used?

If the DAG structure was preserved, toStringNoDupes would never need to
work with a list containing duplicate flags, including libraries like
-ldl and -lm, because the topological sort would never have created
duplicates in the first place.