convert can't handle conditional track_features: (in onednn-feedstock)

[mgorny]

What happened?
When trying to convert conda-forge/onednn-feedstock@15fa3b7, I'm getting:

$ conda-recipe-manager  convert --debug recipe/meta.yaml  
EXCEPTION: An exception occurred while parsing the recipe file
list index out of range
0 errors and 0 warnings were found.

FWICS, the problem is:

      {% if dnnl_cpu_runtime != "omp" %}
      track_features:
        - onednn-{{ dnnl_cpu_runtime }}
      {% endif %}

https://github.com/conda-forge/onednn-feedstock/blob/15fa3b7a7108feb8eac4a9aee401956911e72580/recipe/meta.yaml#L24-L27

(I'm guessing that because changing it to:

      track_features:
        - onednn-{{ dnnl_cpu_runtime }}  # [dnnl_cpu_runtime != "omp"]

makes the problem go away)

To Reproduce

Steps to reproduce the behavior:

git clone https://github.com/conda-forge/onednn-feedstock
cd onednn-feedstock
git checkout 15fa3b7a7108feb8eac4a9aee401956911e72580
conda-recipe-manager convert recipe/meta.yaml

Additional Details (please complete the following information):

• OS: Gentoo Linux amd64
• Conda Recipe Manager version: 0.4.0, also reproduced with e2bf2cb
• Any other context about the problem that was found.

[schuylermartin45]

I am going to mark this as a duplicate of #258 and close the issue. But thank you so much for reporting this with such detail! I really appreciate it.

Parsing and handling these conditional and loop macros is a non trivial amount of work, especially given we are trying to move to a format that forbids them entirely. If I wasn't so resource constrained, I might feel differently.

The data I've collected also suggests that there really aren't that many recipes that use these kinds of macros. BUT I'm so glad you used a selector as a work around! I speculate that most of these ifdefs can be manually converted to a selector before running convert faster than it would take to implement full parsing support.

Now that I've said that out loud, maybe there's a hacky work around where we don't fully parse the macros. It'll likely be some nasty regex solution, but that might offer some middle ground solution. I'll make a note in the other ticket.

[mgorny]

Ah, sorry, I really should have searched for if 🤦.

[schuylermartin45]

No worries, happens to me all the time!