Fix pip-install workflow to prevent artifact corruption

The previous workflow built distribution files on every OS/Python combination,
then tried to merge all artifacts together. This caused tarball corruption
during PyPI upload with 'zlib.error: invalid distance too far back'.

For pure Python packages, distribution files should be built only once.

Changes:
- Split workflow into three jobs: build, test, upload_pypi
- Build job: Runs once on ubuntu-latest with Python 3.11, creates sdist and wheel
- Test job: Downloads built artifacts and tests installation on all OS/Python combinations
- Upload job: Depends on both build and test, uploads single set of artifacts to PyPI

This prevents multiple builds of the same files and eliminates artifact conflicts.

Author: RoryBarnes

.github/workflows/pip-install.yml

@@ -8,12 +8,8 @@ on:
 jobs:
 
   build:
-    name: 'py${{ matrix.python }} on ${{ matrix.os }}'
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [macos-15-intel, macos-26, ubuntu-22.04, ubuntu-24.04]
-        python: ['3.9', '3.10', '3.11', '3.12', '3.13', '3.14']
+    name: Build distribution
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
         with:
@@ -23,14 +19,38 @@ jobs:
       - uses: actions/setup-python@v5
         name: Install Python
         with:
-          python-version: ${{ matrix.python }}
-          allow-prereleases: true
+          python-version: '3.11'
 
       - name: Build
         run: |
           python -m pip install -U pip build twine setuptools setuptools_scm wheel
           python -m build
 
+      - uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/*
+
+  test:
+    name: 'Test py${{ matrix.python }} on ${{ matrix.os }}'
+    needs: [build]
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [macos-15-intel, macos-26, ubuntu-22.04, ubuntu-24.04]
+        python: ['3.9', '3.10', '3.11', '3.12', '3.13', '3.14']
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: dist
+          path: dist
+
+      - uses: actions/setup-python@v5
+        name: Install Python
+        with:
+          python-version: ${{ matrix.python }}
+          allow-prereleases: true
+
       - name: Test the sdist
         run: |
           python -m venv venv-sdist
@@ -43,22 +63,16 @@ jobs:
           venv-wheel/bin/python -m pip install dist/vspace*.whl
           venv-wheel/bin/python -c "import vspace; print(vspace.__version__)"
 
-      - uses: actions/upload-artifact@v4
-        with:
-          name: dist-${{ matrix.os }}-${{ matrix.python }}
-          path: dist/*
-
   upload_pypi:
-    needs: [build]
+    needs: [build, test]
     runs-on: ubuntu-latest
     if: github.event_name == 'release' && github.event.action == 'published'
     permissions:
       id-token: write
     steps:
       - uses: actions/download-artifact@v4
         with:
-          pattern: dist-*
+          name: dist
           path: dist
-          merge-multiple: true
 
       - uses: pypa/gh-action-pypi-publish@release/v1

.github/workflows/tests.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-22.04, ubuntu-24.04, macos-15-intel, macos-latest]
+        os: [ubuntu-22.04, ubuntu-24.04, macos-15-intel, macos-26]
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
 
     steps: