Rebuild for pytorch 2.8

[regro-cf-autotick-bot]

This PR has been triggered in an effort to update pytorch28.

Notes and instructions for merging this PR:

1. Please merge the PR only after the tests have passed.
2. Feel free to push to the bot's branch to update this PR if needed.

Please note that if you close this PR we presume that the feedstock has been rebuilt, so if you are going to perform the rebuild yourself don't close this PR until the your rebuild has been merged.

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[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/recipe.yaml) and found it was in an excellent condition.

I do have some suggestions for making it better though...

For recipe/recipe.yaml:

• ℹ️ No valid build backend found for Python recipe for package `` using pip. Python recipes using `pip` need to explicitly specify a build backend in the `host` section. If your recipe has built with only `pip` in the `host` section in the past, you likely should add `setuptools` to the `host` section of your recipe.
• ℹ️ No valid build backend found for Python recipe for package `` using pip. Python recipes using `pip` need to explicitly specify a build backend in the `host` section. If your recipe has built with only `pip` in the `host` section in the past, you likely should add `setuptools` to the `host` section of your recipe.
• ℹ️ No valid build backend found for Python recipe for package `` using pip. Python recipes using `pip` need to explicitly specify a build backend in the `host` section. If your recipe has built with only `pip` in the `host` section in the past, you likely should add `setuptools` to the `host` section of your recipe.

_{This message was generated by GitHub Actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/18266334075. Examine the logs at this URL for more detail.}

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.

[weiji14]

The linux-aarch64 jobs are failing with a dependency conflict.

  ╰─▶ Cannot solve the request because of: pytorch * cuda* cannot be installed
      because there are no viable options:
      ├─ pytorch 2.8.0 | 2.8.0 | 2.8.0 would require
      │  └─ python >=3.10,<3.11.0a0, for which no candidates were found.
        ...
      └─ pytorch 2.8.* cannot be installed because there are no viable
      options:
         ├─ pytorch 2.8.0 would require
         │  ├─ libcudss0 >=0.4.0.2,<0.4.1.0a0, which can be installed with any
      of the following options:
         │  └─ libtorch ==2.8.0 cuda129_generic_h4d1ebf7_200, which cannot be
      installed because there are no viable options:
         │     └─ libtorch 2.8.0 would require
         │        └─ libcudss >=0.6.0.5,<0.6.1.0a0, which cannot be installed
      because there are no viable options:
         └─ pytorch 2.8.0, which conflicts with the versions reported above.

Looks like conda-forge/pytorch-cpu-feedstock#422.

[carterbox]

I wasn't aware that multi-output recipes were supported by any implementation of the v1 recipe. Does it build correctly without the --experimental flag for rattler?

[weiji14]

I wasn't aware that multi-output recipes were supported by any implementation of the v1 recipe. Does it build correctly without the --experimental flag for rattler?

From https://github.com/search?type=code&q=org%3Aconda-forge+path%3Arecipe%2Frecipe.yaml+outputs&p=2, I see about 100+ feedstocks that seem to be using multi-output recipes already, so it should be supported? Doesn't seem to be experimental either, I see the docs are under https://rattler.build/latest/reference/recipe_file/#outputs-section and not in the experimental features page.

[carterbox]

https://rattler.build/latest/reference/recipe_file/#outputs-section:

Each output is built independently. You should take care of not packaging the same files twice.

My interpretation is that you cannot build one package and split it which is what we were doing here. You can only build a package and then create some meta packages or build secondary packages separately. "cache for multiple outputs" is the feature that is closest to what we were doing with the v0 recipe.

[weiji14]

https://rattler.build/latest/reference/recipe_file/#outputs-section:

Each output is built independently. You should take care of not packaging the same files twice.

My interpretation is that you cannot build one package and split it which is what we were doing here. You can only build a package and then create some meta packages or build secondary packages separately. "cache for multiple outputs" is the feature that is closest to what we were doing with the v0 recipe.

Ah I totally missed that, now it makes sense why there was a top-level requirements: build: section. So we'll need to wait for conda-forge/conda-smithy#2057 and conda/ceps#102 it seems for v1 to work.

I'll revert back to v0 then, but will do this after conda-forge/pytorch-cpu-feedstock#422 is resolved.