how about this

Author: joshuadavidthomas

.github/workflows/test.yml

@@ -19,7 +19,7 @@ jobs:
   generate-matrix:
     runs-on: ubuntu-latest
     outputs:
-      matrix: ${{ steps.set-matrix.outputs.matrix }}
+      include: ${{ steps.set-matrix.outputs.include }}
     steps:
       - uses: actions/checkout@v4
 
@@ -29,7 +29,7 @@ jobs:
           enable-cache: true
           pyproject-file: pyproject.toml
 
-      - id: set-matrix
+      - id: set-include
         run: |
           uv run noxfile.py --session gha_matrix
 
@@ -40,7 +40,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        include: ${{ fromJSON(needs.generate-matrix.outputs.matrix.include) }}
+        include: ${{ fromJSON(needs.generate-matrix.outputs.matrix) }}
     steps:
       - uses: actions/checkout@v4
 

noxfile.py

@@ -124,19 +124,17 @@ def lint(session):
 
 @nox.session
 def gha_matrix(session):
-    sessions = session.run("nox", "-l", "--json", silent=True)
-    matrix = {
-        "include": [
-            {
-                "django-version": session["call_spec"]["django"],
-                "python-version": session["python"],
-            }
-            for session in json.loads(sessions)
-            if session["name"] == "tests"
-        ]
-    }
+    sessions = session.run("nox", "-l", "--json", external=True, silent=True)
+    matrix = [
+        {
+            "django-version": session["call_spec"]["django"],
+            "python-version": session["python"],
+        }
+        for session in json.loads(sessions)
+        if session["name"] == "tests"
+    ]
     with Path(os.environ["GITHUB_OUTPUT"]).open("a") as fh:
-        print(f"matrix={matrix}", file=fh)
+        print(f"include={matrix}", file=fh)
 
 
 if __name__ == "__main__":