Action: Replace deprecated set-output command

The set-output workflow command has been deprecated [1] and replaced
with writing to an environment file. Update .github/action_helper.py
to use the new file.

[1] https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

.github/action_helper.py

@@ -65,9 +65,9 @@ def setup_action(input_: str) -> None:
     if len(versions) > 20:
         raise ValueError(f"too many interpreters to install: {len(versions)} > 20")
 
-    print(f"::set-output name=interpreter_count::{len(versions)}")
+    print(f"interpreter_count={len(versions)}")
     for i, version in enumerate(versions):
-        print(f"::set-output name=interpreter_{i}::{version}")
+        print(f"interpreter_{i}={version}")
 
 
 if __name__ == "__main__":

action.yml

@@ -21,7 +21,7 @@ runs:
     - name: "Validate input"
       id: helper
       run: >
-        '${{ steps.localpython.outputs.python-path }}' '${{ github.action_path }}/.github/action_helper.py' '${{ inputs.python-versions }}'
+        '${{ steps.localpython.outputs.python-path }}' '${{ github.action_path }}/.github/action_helper.py' '${{ inputs.python-versions }}' >>${GITHUB_OUTPUT}
       shell: bash
 
     - uses: actions/setup-python@v4

tests/test_action_helper.py

@@ -43,43 +43,41 @@ def test_filter_version_invalid_minor():
 
 VALID_VERSION_LISTS = {
     "3.7, 3.8, 3.9, 3.10, pypy-3.7, pypy-3.8, pypy-3.9": [
-        "::set-output name=interpreter_count::7",
-        "::set-output name=interpreter_0::pypy-3.7",
-        "::set-output name=interpreter_1::pypy-3.8",
-        "::set-output name=interpreter_2::pypy-3.9",
-        "::set-output name=interpreter_3::3.7",
-        "::set-output name=interpreter_4::3.8",
-        "::set-output name=interpreter_5::3.9",
-        "::set-output name=interpreter_6::3.10",
+        "interpreter_count=7",
+        "interpreter_0=pypy-3.7",
+        "interpreter_1=pypy-3.8",
+        "interpreter_2=pypy-3.9",
+        "interpreter_3=3.7",
+        "interpreter_4=3.8",
+        "interpreter_5=3.9",
+        "interpreter_6=3.10",
     ],
     "": [
-        "::set-output name=interpreter_count::1",
-        "::set-output name=interpreter_0::3.10",
+        "interpreter_count=1",
+        "interpreter_0=3.10",
     ],
     "3.10.4": [
-        "::set-output name=interpreter_count::1",
-        "::set-output name=interpreter_0::3.10.4",
+        "interpreter_count=1",
+        "interpreter_0=3.10.4",
     ],
     "3.9-dev,pypy3.9-nightly": [
-        "::set-output name=interpreter_count::3",
-        "::set-output name=interpreter_0::pypy3.9-nightly",
-        "::set-output name=interpreter_1::3.9-dev",
-        "::set-output name=interpreter_2::3.10",
+        "interpreter_count=3",
+        "interpreter_0=pypy3.9-nightly",
+        "interpreter_1=3.9-dev",
+        "interpreter_2=3.10",
     ],
     "3.10, 3.9, 3.8": [
-        "::set-output name=interpreter_count::3",
-        "::set-output name=interpreter_0::3.9",
-        "::set-output name=interpreter_1::3.8",
-        "::set-output name=interpreter_2::3.10",
+        "interpreter_count=3",
+        "interpreter_0=3.9",
+        "interpreter_1=3.8",
+        "interpreter_2=3.10",
     ],
-    ",".join(f"3.{minor}" for minor in range(20)): [
-        "::set-output name=interpreter_count::20"
-    ]
+    ",".join(f"3.{minor}" for minor in range(20)): ["interpreter_count=20"]
     + [
-        f"::set-output name=interpreter_{i}::3.{minor}"
+        f"interpreter_{i}=3.{minor}"
         for i, minor in enumerate(minor_ for minor_ in range(20) if minor_ != 10)
     ]
-    + ["::set-output name=interpreter_19::3.10"],
+    + ["interpreter_19=3.10"],
 }