Add v1 recipe debugging using py-rattler-build

[jsmolic]

Description

This PR introduces support for debugging v1 recipes using
py-rattler-build's debug API [1].

While py-rattler-build provides more functionality, we are currently
using it only to setup debug environment and scripts, to match
conda-debug's behavior with v0 recipes.

The process loads and renders the recipe, and invokes
DebugSession.create() method to setup the environment before printing
debugging instructions to the console.

[1] https://rattler-build.prefix.dev/dev/py-rattler-build/reference/debug/

NOTE: This PR depends on #5924

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[codspeed-hq]

Merging this PR will not alter performance

✅ 5 untouched benchmarks

---

_{Comparing jsmolic:v1-integration-debug (213cb88) with main (abcbaeb)¹}

Footnotes

1. No successful run was found on main (56b320b) during the generation of this report, so abcbaeb was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[jsmolic]

Example debug session:

recipe.yaml:

schema_version: 1

context:
  name: myproject
  version: "2.0.0"

recipe:
  version: ${{ version }}

outputs:
  # First output: The library
  - package:
      name: ${{ name }}-lib
    build:
      script:
        interpreter: python
        content: |
          import os
          from pathlib import Path

          prefix = Path(os.environ["PREFIX"])
          lib_dir = prefix / "lib" / "python"
          lib_dir.mkdir(parents=True, exist_ok=True)

          (lib_dir / "myproject_lib.py").write_text('VERSION = "2.0.0"')
          print(f"Created library at {lib_dir}")
    requirements:
      build:
        - python

  # Second output: Uses the library as a host dependency
  - package:
      name: ${{ name }}-tools
    build:
      script:
        interpreter: python
        content: |
          import os
          from pathlib import Path

          prefix = Path(os.environ["PREFIX"])

          # Read and print the lib file (installed as host dependency)
          lib_file = prefix / "lib" / "python" / "myproject_lib.py"
          print(f"Reading library from: {lib_file}")
          print(lib_file.read_text())
    requirements:
      build:
        - python
      host:
        - ${{ name }}-lib%

$ conda-debug test-recipe --output-id myproject-tools
-No sources to fetch
Adding 0 packages to subdir linux-64.
Successfully added 0 packages to subdir linux-64.
Writing repodata to linux-64/repodata.json
Adding 0 packages to subdir noarch.
Successfully added 0 packages to subdir noarch.
Writing repodata to noarch/repodata.json
  Platform: linux-64 [__unix=0=0, __linux=5.15.32=0, __glibc=2.40=0, __archspec=1=zen3]
  Channels: 
   - file:///home/jakov/miniforge3/conda-bld/
   - conda-canary
   - conda-forge
   - https://repo.anaconda.com/pkgs/main/
   - https://repo.anaconda.com/pkgs/r/
  Specs:
   - python
sharded repodata seems to be missing for https://conda.anaconda.org/conda-canary/linux-64/, falling back to repodata.json files
sharded repodata seems to be missing for https://conda.anaconda.org/conda-canary/noarch/, falling back to repodata.json files
sharded repodata seems to be missing for https://repo.anaconda.com/pkgs/main/linux-64/, falling back to repodata.json files
sharded repodata seems to be missing for https://repo.anaconda.com/pkgs/r/linux-64/, falling back to repodata.json files
sharded repodata seems to be missing for https://repo.anaconda.com/pkgs/main/noarch/, falling back to repodata.json files
sharded repodata seems to be missing for https://repo.anaconda.com/pkgs/r/noarch/, falling back to repodata.json files
- ⠁ Downloading repodata [00:00:00] [────────────────────────────────────────]      0 B @ 0 B/s                            ⠂ Downloading repoda   Downloadin ⠁ solving                          ⠉ solving                                            
╭──────────────────┬───────────┬──────────────────────┬─────────────┬─────────────╮
│ Package          ┆ Version   ┆ Build                ┆ Channel     ┆        Size │
╞══════════════════╪═══════════╪══════════════════════╪═════════════╪═════════════╡
│ _libgcc_mutex    ┆ 0.1       ┆ main                 ┆ conda-forge ┆    2.46 KiB │
│ _openmp_mutex    ┆ 5.1       ┆ 1_gnu                ┆ main        ┆   20.82 KiB │
│ bzip2            ┆ 1.0.8     ┆ hda65f42_9           ┆ conda-forge ┆  254.08 KiB │
│ ca-certificates  ┆ 2026.4.22 ┆ hbd8a1cb_0           ┆ conda-forge ┆  127.97 KiB │
│ icu              ┆ 78.3      ┆ h33c6efd_0           ┆ conda-forge ┆   12.13 MiB │
│ ld_impl_linux-64 ┆ 2.45.1    ┆ default_hbd61a6d_102 ┆ conda-forge ┆  710.94 KiB │
│ libexpat         ┆ 2.7.5     ┆ hecca717_0           ┆ conda-forge ┆   74.83 KiB │
│ libffi           ┆ 3.5.2     ┆ h3435931_0           ┆ conda-forge ┆   57.22 KiB │
│ libgcc           ┆ 15.2.0    ┆ he0feb66_18          ┆ conda-forge ┆ 1017.37 KiB │
│ libgcc-ng        ┆ 15.2.0    ┆ h69a702a_18          ┆ conda-forge ┆   26.88 KiB │
│ libgomp          ┆ 15.2.0    ┆ he0feb66_18          ┆ conda-forge ┆  589.12 KiB │
│ liblzma          ┆ 5.8.3     ┆ hb03c661_0           ┆ conda-forge ┆  110.82 KiB │
│ libmpdec         ┆ 4.0.0     ┆ hb03c661_1           ┆ conda-forge ┆   90.23 KiB │
│ libsqlite        ┆ 3.53.0    ┆ hf4e2dac_0           ┆ conda-forge ┆  936.39 KiB │
│ libstdcxx        ┆ 15.2.0    ┆ h934c35e_18          ┆ conda-forge ┆    5.58 MiB │
│ libuuid          ┆ 2.42      ┆ h5347b49_0           ┆ conda-forge ┆   39.35 KiB │
│ libxcb           ┆ 1.17.0    ┆ h9b100fa_0           ┆ main        ┆  430.36 KiB │
│ libzlib          ┆ 1.3.2     ┆ h25fd6f3_2           ┆ conda-forge ┆   62.14 KiB │
│ ncurses          ┆ 6.6       ┆ hdb14827_0           ┆ conda-forge ┆  897.42 KiB │
│ openssl          ┆ 3.6.2     ┆ h35e630c_0           ┆ conda-forge ┆    3.02 MiB │
│ pthread-stubs    ┆ 0.4       ┆ hb9d3cd8_1002        ┆ conda-forge ┆    8.06 KiB │
│ python           ┆ 3.14.4    ┆ habeac84_100_cp314   ┆ conda-forge ┆   35.01 MiB │
│ python_abi       ┆ 3.14      ┆ 8_cp314              ┆ conda-forge ┆    6.83 KiB │
│ readline         ┆ 8.3       ┆ h853b02a_0           ┆ conda-forge ┆  336.99 KiB │
│ tk               ┆ 8.6.15    ┆ h54e0aa7_0           ┆ main        ┆    3.44 MiB │
│ tzdata           ┆ 2026a     ┆ he532380_0           ┆ main        ┆  117.19 KiB │
│ xorg-libx11      ┆ 1.8.13    ┆ he1eb515_0           ┆ conda-forge ┆  819.97 KiB │
│ xorg-libxau      ┆ 1.0.12    ┆ hb03c661_1           ┆ conda-forge ┆   14.96 KiB │
│ xorg-libxdmcp    ┆ 1.1.5     ┆ hb03c661_1           ┆ conda-forge ┆   20.11 KiB │
│ zlib             ┆ 1.3.2     ┆ h25fd6f3_2           ┆ conda-forge ┆   93.68 KiB │
│ zstd             ┆ 1.5.7     ┆ hb78ec9c_6           ┆ conda-forge ┆  587.28 KiB │
╰──────────────────┴───────────┴──────────────────────┴─────────────┴─────────────╯
   Downloading repodata [00:00:00] Done
   Downloading repodata [00:00:01] Done
   Downloading repodata [00:00:00] Done
   Downloading repodata [00:00:01] Done
   Downloading repodata [00:00:01] Done
   Downloading repodata [00:00:00] Done

╭───────────────┬─────────┬────────────┬───────────┬──────────╮
│ Package       ┆ Version ┆ Build      ┆ Channel   ┆     Size │
╞═══════════════╪═════════╪════════════╪═══════════╪══════════╡
│ myproject-lib ┆ 2.0.0   ┆ hb0f4dca_0 ┆ conda-bld ┆ 5.50 KiB │
╰───────────────┴─────────┴────────────┴───────────┴──────────╯

Finalized run dependencies: this output has no run dependencies

   validate cache       31 packages in 6ms
   installing packages  took 340ms                                                                                                                                                                                                                                                                                                                                                                                                             Successfully updated the build environment
   validate cache       1 package in 0s
   installing packages  took 4ms                                                                                                                                                                                                                                                                                                                                                                                                               Successfully updated the host environment
Build script created at /home/jakov/miniforge3/conda-bld/bld/rattler-build_myproject-tools/work/conda_build.sh
Host dependencies available in /home/jakov/miniforge3/conda-bld/bld/rattler-build_myproject-tools/host_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold

To run the actual build, use:
rattler-build build --recipe-dir /home/jakov/test/test-recipe
Or run the build script directly with:
cd /home/jakov/miniforge3/conda-bld/bld/rattler-build_myproject-tools/work && ./conda_build.sh

I'll add a test for debug to this PR shortly

[jaimergp]

To run the actual build, use:
rattler-build build --recipe-dir /home/jakov/test/test-recipe
Or run the build script directly with:
cd /home/jakov/miniforge3/conda-bld/bld/rattler-build_myproject-tools/work && ./conda_build.sh

Should we use rattler-build there or conda build /home/jakov/test/test-recipe? conda-build users may be confused about those tools mentioned here.

[jsmolic]

To run the actual build, use:
rattler-build build --recipe-dir /home/jakov/test/test-recipe
Or run the build script directly with:
cd /home/jakov/miniforge3/conda-bld/bld/rattler-build_myproject-tools/work && ./conda_build.sh

Should we use rattler-build there or conda build /home/jakov/test/test-recipe? conda-build users may be confused about those tools mentioned here.

oh yes, I was going to use conda-build there, it makes sense to recommend it now that it supports v1 recipes, but rattler ended up somehow, will fix that up

[jsmolic]

Hmm there is a newly added v1 recipe test on windows that seems to be flaky, need to investigate why is that