relax filename size restriction for hotfiles

[rsoutelino]

The current limit for the fname option in the HOTSINGLE and HOTMULTIPLE subcomponents is 36 characters, which can be a bit restrictive for long hierarchical pathnames in filesystems, as in the example below.

I make a suggestion here to increase that limit to 80, assuming there are no other drawbacks. I was initially working around that by copying/renaming the hotfile, but it may be handy to have the actual full path of the file in the declarative YAML configuration as a reference for programatically checking for hotfile existence, in workflows where you want to branch out to automatic spinup triggers based on hotfile absence.

No particular reason for suggesting max_length=80 as the new limit, just arbitrarily used Python pep8 as a reference. I'm also not sure if there are any other drawbacks to increasing this limit or perhaps not having a limit at all, so just putting this forward as a possible change.

config:
  model_type: swan
  startup:

  cgrid:
  
  inpgrid:

  boundary:
   
  initial:
    kind:
      model_type: hotsingle
      fname: /some/long/hierarchical/path/forecast/prod/model/cycle/model.hot
      format: free

I've tested it locally with SWAN 41.45, and it looks like the model accepts such long pathnames INPUT file in the Boundary and Initial conditions section (as below). The model ran without errors with that INPUT file.

! Boundary and Initial conditions -------------------------------------------------------------------------------------------------------------------------------------------------

BOUNDNEST1 NEST 'model.bnd' CLOSED

INITIAL HOTSTART SINGLE fname=' /some/long/hierarchical/path/forecast/prod/model/cycle/model.hot' FREE

Cheers

[rafa-guedes]

Thanks @rsoutelino