[MacPorts] #55139: RFE: Improve Compiler Management Code

[MacPorts]

#55139: RFE: Improve Compiler Management Code
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  Reporter:  MarcusCalhoun-Lopez  |      Owner:
      Type:  enhancement          |     Status:  new
  Priority:  Normal               |  Milestone:
 Component:  base                 |    Version:
Resolution:                       |   Keywords:
      Port:                       |
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Comment (by seanfarley):

 I can try to provide some backstory for the compilers portgroup:

 The compilers portgroup serves a (minor-ish) purpose of providing some
 compatibility between different versions of fortran in combination with
 gcc or clang/llvm. For instance, as a user I could say, "I want to install
 superlu and mumps with avx" to which the command would be `port install
 superlu +clang +gfortran` and that would make sure the dependencies all
 match.

 This becomes a major problem when considering mpi ports. For those that
 don't know, both mpich and openmpi are just compiler wrappers. You can see
 which compiler was used for either mpich or openmpi by `mpicc -show`. For
 a port like petsc, all it wants is "give me a mpi library" which, for
 better or worse, means supplying the correct compiler wrapper. Does the
 user want mpich with gcc? mpich with clang? openmpi with gcc? The
 combinatorial explosion is what I tried to wrangle with the compilers and
 mpi portgroups.

 One could argue that the inability to depend on variants is what this
 boils down to. I dunno. Regardless, keeping in mind the downstream
 dependents (mpi and friends) is very important when considering changing
 the compilers portgroup (concrete example: dolfin depends on boost+mpi).

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Ticket URL: <https://trac.macports.org/ticket/55139#comment:8>
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