fsl.FNIRT does not generate fieldcoeff_file when it is an output connection

[mwaskom]

Summary

When using fsl.FNIRT you have to set fieldcoeff_file=True in the inputs even when the fieldcoeff_file output is connected to a downstream node.

Actual behavior

No fieldcoeff_file is written and the downstream node errors out.

Expected behavior

Shouldn't there be an association between the input and output traits fieldcoeff_file be written with a default filename and passed to the downstream node? It's been so long that I've dealt with the Interface guts that I forget how this works ...

[mgxd]

@mwaskom looks like there is no default value for fieldcoeff_file - thus it doesn't get extracted for the outputs dict unless explicitly specified since it's left Undefined

[mwaskom]

So remind me, to fix this I need to add genfile=True in the input spec and then add fieldcoeff_file to this list?

[mgxd]

If fieldcoeff_file can always be created, just adding default=True should suffice. If not, then this is intended behavior, as I don't believe interfaces' outputs can be dependent on workflow connections with this current engine

[mwaskom]

By "can always be created" you mean can be created by an interface with only the mandatory inputs set?

How is the suffix determined with default=True? Is there an example Interface you can point me to?

[mgxd]

By "can always be created" you mean can be created by an interface with only the mandatory inputs set?

Yes, that's a better way to say it 👍

How is the suffix determined with default=True? Is there an example Interface you can point me to?

By setting default=True, I believe it'll go down this path by default and automatically generate the file. The suffix is determined from a hardcoded dict filemap

[mgxd]

@mwaskom is this all set?

[mwaskom]

No, it needs a PR, I just haven't had time for it.

[Dhananjay4yu]

i did like to help