create string YAML block

add test

use platforms

debugging print output

use arguments `fill`, `fill_platforms`, `fill_factors`

Author: zacharyburnett

.github/workflows/test_tox.yml

@@ -79,6 +79,16 @@ jobs:
           posargs: 'PyPy'
       pytest: false
 
+  test_supported_pythons:
+    uses: ./.github/workflows/tox.yml
+    with:
+      envs: |
+        - linux: py3
+      fill: true
+      fill_platforms: linux
+      fill_factors: xdist
+      pytest: false
+
   test_libraries:
     uses: ./.github/workflows/tox.yml
     with:

.github/workflows/tox.yml

@@ -7,7 +7,6 @@
 #     "packaging==25.0",
 # ]
 # ///
-import json
 import os
 import warnings
 from pathlib import Path
@@ -21,26 +20,40 @@
 
 @click.command()
 @click.option("--source", default=None)
-@click.option("--flags", default=None)
+@click.option("--factors", default=None)
 @click.option("--no-eoas", is_flag=True, default=False)
-def load_supported_python_toxenvs(
+@click.option("--platforms", default=None)
+def supported_python_envs_block(
     source: Path = None,
-    flags: list[str] = None,
+    factors: list[str] = None,
     no_eoas: bool = False,
+    platforms: list[str] = None,
 ):
     """enumerate toxenvs Python from a package source"""
 
-    toxenvs = supported_python_toxenvs(source, flags, no_eoas)
-    print(json.dumps(toxenvs, indent=2))
+    if platforms is None:
+        platforms = ["linux"]
+    elif isinstance(platforms, str):
+        platforms = platforms.split(",")
+
+    toxenvs = supported_python_toxenvs(source, factors, no_eoas)
+    envs_block = "\\n".join(
+        f"- {platform}: {toxenv}" for platform in platforms for toxenv in toxenvs
+    )
+
+    print(envs_block)
     with open(os.environ["GITHUB_OUTPUT"], "a") as f:
-        f.write(f"envs={json.dumps(toxenvs)}\n")
+        f.write(f"envs={envs_block}\n")
 
 
 def supported_python_toxenvs(
     source: Path = None,
-    flags: list[str] = None,
+    factors: list[str] = None,
     no_eoas: bool = False,
 ) -> list[str]:
+    if isinstance(factors, str):
+        factors = factors.split(",")
+
     current_pythons = current_python_versions(no_eoas=no_eoas)
 
     if source is None or source == "":
@@ -50,15 +63,17 @@ def supported_python_toxenvs(
         try:
             python_requirements = SpecifierSet(configuration["project"]["requires-python"])
 
-            supported_pythons = [python for python in current_pythons if python in python_requirements]
+            supported_pythons = [
+                python for python in current_pythons if python in python_requirements
+            ]
         except (KeyError, TypeError):
             warnings.warn(
                 "could not find `requires-python` in metadata; falling back to current Python versions..."
             )
             supported_pythons = current_pythons
 
     return [
-        f"py{str(python).replace('.', '')}{'-' + '-'.join(flags) if flags is not None and len(flags) > 0 else ''}"
+        f"py{str(python).replace('.', '')}{'-' + '-'.join(factors) if factors is not None and len(factors) > 0 else ''}"
         for python in supported_pythons
     ]
 
@@ -77,4 +92,4 @@ def current_python_versions(no_eoas: bool = False) -> list[Version]:
 
 
 if __name__ == "__main__":
-    load_supported_python_toxenvs()
+    supported_python_envs_block()

tools/supported_pythons.py

@@ -37,7 +37,7 @@ def load_tox_targets(envs, libraries, posargs, toxdeps, toxargs, pytest, pytest_
                      cache_restore_keys, artifact_path, runs_on, default_python, timeout_minutes):
     """Script to load tox targets for GitHub Actions workflow."""
     # Load envs config
-    envs = yaml.load(envs, Loader=yaml.BaseLoader)
+    envs = yaml.load(envs.replace("\\n", "\n"), Loader=yaml.BaseLoader)
     print(json.dumps(envs, indent=2))
 
     # Load global libraries config