devxlib back compatibility broken in 5.3

[andreamarini]

From version 5.3 it is not possible to compile Yambo linking a devxlib version previously compiled (before the merge in 5.3).

Error is

WF_symm_kpoint_incl.f90:51:25:

   51 |  use devxlib,       ONLY:devxlib_conjg_d,devxlib_memcpy_d2d,devxlib_memset_d
      |                         1
Error: Symbol ‘devxlib_conjg_d’ referenced at (1) not found in module ‘devxlib’
WF_symm_kpoint_incl.f90:166:25:

  166 |  use devxlib,       ONLY:devxlib_conjg_d,devxlib_memcpy_d2d,devxlib_memset_d
      |                         1
Error: Symbol ‘devxlib_conjg_d’ referenced at (1) not found in module ‘devxlib’

It would be desiderable to have a check the configure time and/or to create a stamp with the currently installed version in order to force the code to recompile.

As it is now anyone using the pre-compiled libs would'nt be able to compile the code.

[andrea-ferretti]

Hi Andrea,
I think devXlib has changed the interface of devxlib_conjg_d with release 0.8.5 ( see commit 9d11831 for the inclusion into Yambo).

I think the issue you see has to do with the way Yambo stores libraries in lib/external, which does not track the version of the lib (which are updated only rarely)...

Basically, on updates, one would nee to clean lib/external (I agree a more straightforward logic could be implemented)

[sangallidavide]

Yambo 5.2 did not depend on the deviceXlib library.

Yambo 5.3 is the first release which depends on the deviceXlib library. deviceXlib 0.8.5 is the first version supported.
Anything else was just a transitional version.

More in general, at present, for the internally compiled external libraries, yambo just checks that they exist. It would be better to always check existing external library, regardless of where they come from (e.g. internally compiled or system provided).