Conditionally build Python-dependent Lyrical libraries across Pythons 3.12-3.14

AGENTS.md

@@ -21,6 +21,10 @@ to read without Claude):
   into `distros/<d>/`.
 - Run everything per distribution with `pixi run rs <distro> <task>`, from the
   repository root. Package names are `ros2-<pkg>` (dashes), e.g. `ros2-rsl`.
+- lyrical builds packages with Python content for Python 3.12-3.14 and the others once
+  (`conditional_python_dependency`, see README "Python versions"). A built-once package
+  that fails its `package_contents` test ships Python after all: add `python` to its
+  `add_host` in `patch/dependencies.yaml`.
 - Never edit `conda_build_config.yaml` by hand: change `shared/pinning/` or the
   distribution's `distro.yaml`, then `pixi run rs <distro> render-pinning` (CI checks it).
 - A change outside `distros/` rebuilds every distribution in CI; keep such PRs focused.
@@ -51,6 +55,7 @@ pixi run rs <d> build --continue-on-failure     # everything missing on the chan
 pixi run rs <d> check-patches [--recipe ros2-<pkg>]
 pixi run rs <d> check-deps                      # pin conflicts, before building anything
 pixi run rs <d> gap-report                      # recipes without artifacts and vice versa
+pixi run rs <d> python-audit [--elf]            # per-Python vs built-once recipes against the published packages
 pixi run rs add-package <pkg>... [<d>...]       # select packages (as the bot does)
 pixi run rs check                               # sanity checks (CI)
 ```

README.md

@@ -106,6 +106,16 @@ pixi run rs check                             # sanity checks (also run in CI)
 of a distribution uses `full_rebuild: true` there. A new build number goes into its
 `pkg_additional_info.yaml` (one package) or `vinca.yaml` (everything).
 
+**Python versions:** a distribution's `pinning_overrides` can list several Pythons, as
+lyrical does for 3.12-3.14. With `conditional_python_dependency: true` in its
+`vinca.yaml`, only packages with Python content (Python modules, rosidl Python bindings,
+extensions) get python in host/run and are built once per Python; the others are built
+once, without a `python_abi` dependency, and fail their build if they ship
+`site-packages` content or a CPython extension anyway. When vinca's guess from
+`package.xml` is wrong, add `python` to the package's `add_host` (or `remove_host`) in
+`patch/dependencies.yaml`. `pixi run rs <distro> python-audit [--elf]` compares the
+guess with the published packages and lists the misses.
+
 **Building only some distributions in a PR:** a PR builds the distributions it changes,
 and all of them as soon as it touches anything outside `distros/<distro>/`. To limit
 that (e.g. a humble rebuild that also changes `shared/` or `tools/`), add the label

distros/lyrical/conda_build_config.yaml

@@ -1000,23 +1000,26 @@ pythia8:
 python:
   # conda-forge supports only 3.14+ for win-arm64 and linux-riscv64
   # part of a zip_keys: python, is_python_min
+  - 3.12.* *_cpython   # [not ((win and arm64) or riscv64)]
+  - 3.13.* *_cp313     # [not ((win and arm64) or riscv64)]
   - 3.14.* *_cp314
-  - 3.12.* *_cpython
 python_impl:
   - cpython
 
   # ros-lyrical specific (distros/lyrical/distro.yaml)
 python_min:
   # minimum supported python version per CFEP-25
   # bump to next minor version when we drop python versions
-  - '3.11'             # [not ((win and arm64) or riscv64)]
+  - '3.12'             # [not ((win and arm64) or riscv64)]
   - '3.14'             # [(win and arm64) or riscv64]
 is_freethreading:
   - false
 is_python_min:
   # part of a zip_keys: python, is_python_min
-  - false
-  - false
+  - true               # [not ((win and arm64) or riscv64)]
+  - false              # [not ((win and arm64) or riscv64)]
+  - false              # [not ((win and arm64) or riscv64)]
+  - true               # [(win and arm64) or riscv64]
 is_abi3:
   - true
 pytorch:

distros/lyrical/distro.yaml

@@ -7,10 +7,21 @@ upload_to: [prefix, anaconda]
 read_from: prefix
 rosdistro_sync: lyrical/2026-10-05
 pinning_overrides:
-  # build every python package for 3.14 (the shared default) and 3.12;
-  # is_python_min is zipped with python, so it needs one entry per version
-  python: [3.14.* *_cp314, 3.12.* *_cpython]
-  is_python_min: [false, false]
+  # Lyrical supports Python 3.12-3.14 (REP 2000). Packages with Python content are
+  # built for each (vinca.yaml: conditional_python_dependency), the others once.
+  # conda-forge has only 3.14+ for win-arm64 and linux-riscv64, so those get one variant.
+  python:
+    - 3.12.* *_cpython # [not ((win and arm64) or riscv64)]
+    - 3.13.* *_cp313   # [not ((win and arm64) or riscv64)]
+    - 3.14.* *_cp314
+  is_python_min:
+    - true             # [not ((win and arm64) or riscv64)]
+    - false            # [not ((win and arm64) or riscv64)]
+    - false            # [not ((win and arm64) or riscv64)]
+    - true             # [(win and arm64) or riscv64]
+  python_min:
+    - '3.12'           # [not ((win and arm64) or riscv64)]
+    - '3.14'           # [(win and arm64) or riscv64]
   # every pyqt6 6.11.0 build on conda-forge needs qt6-main <=6.11.2, but the shared
   # `6.11` pin resolves to 6.11.3, whose run export (>=6.11.3) rules pyqt6 out: the
   # rqt packages then can't be installed with python_qt_binding. The published

distros/lyrical/vinca.yaml

@@ -3,7 +3,12 @@ ros_distro: lyrical
 patch_dir: patch
 rosdistro_snapshot: rosdistro_snapshot.yaml
 rosdistro_additional_recipes: rosdistro_additional_recipes.yaml
-build_number: 30
+build_number: 31
+# Only packages with Python content get python in host/run, and with it the Python
+# variants of distro.yaml (cp312-cp314); the others are built once, without a
+# python_abi dependency. Override the classification per package with python in
+# add_host (or remove_host) in patch/dependencies.yaml.
+conditional_python_dependency: true
 
 mutex_package:
   version: 0.22.0