CI: cleanup Sage workflow definition

Author: dnicolodi

.github/workflows/sage.yml

@@ -78,13 +78,19 @@ jobs:
           python3 -m pip install --user build
       - name: Run make dist, prepare upstream artifact
         run: |
-          (cd build/pkgs/${{ env.SPKG }}/src && python3 -m build --sdist .) \
-          && mkdir -p upstream && cp build/pkgs/${{ env.SPKG }}/src/dist/*.tar.gz upstream/${{ env.SPKG }}-git.tar.gz \
-          && echo "sage-package create ${{ env.SPKG }} --version git --tarball ${{ env.SPKG }}-git.tar.gz --type=standard" > upstream/update-pkgs.sh \
-          && if [ -n "${{ env.REMOVE_PATCHES }}" ]; then echo "(cd ../build/pkgs/${{ env.SPKG }}/patches && rm -f ${{ env.REMOVE_PATCHES }}; :)" >> upstream/update-pkgs.sh; fi \
-          && echo "sed -i.bak \"/pushdef.*LT_VERSION/s/3[0-9.]*/4/\" ../build/pkgs/python3/spkg-configure.m4" >> upstream/update-pkgs.sh \
-          && echo "sed -i.bak \"/export.*proxy/d\" ../build/bin/sage-spkg" >> upstream/update-pkgs.sh \
-          && ls -l upstream/
+          pushd build/pkgs/${{ env.SPKG }}/src
+          python3 -m build --sdist .
+          popd
+          mkdir -p upstream
+          cp build/pkgs/${{ env.SPKG }}/src/dist/*.tar.gz upstream/${{ env.SPKG }}-git.tar.gz
+          echo "sage-package create ${{ env.SPKG }} --version git --tarball ${{ env.SPKG }}-git.tar.gz --type=standard" > upstream/update-pkgs.sh
+          if [ -n "${{ env.REMOVE_PATCHES }}" ]
+          then
+            echo "(cd ../build/pkgs/${{ env.SPKG }}/patches rm -f ${{ env.REMOVE_PATCHES }}; :)" >> upstream/update-pkgs.sh
+          fi
+          echo "sed -i.bak \"/pushdef.*LT_VERSION/s/3[0-9.]*/4/\" ../build/pkgs/python3/spkg-configure.m4" >> upstream/update-pkgs.sh
+          echo "sed -i.bak \"/export.*proxy/d\" ../build/bin/sage-spkg" >> upstream/update-pkgs.sh
+          ls -l upstream
       - name: System factors for pull requests
         # See https://github.com/sagemath/sage/blob/develop/.github/workflows/docker.yml for available systems
         id: pull-request-systems
@@ -122,14 +128,13 @@ jobs:
     # Use branch u/mkoeppe/numpy_1_23_x__scipy_1_9_x for a fix for uppercase github repo names (FFY00)
     uses: sagemath/sagetrac-mirror/.github/workflows/docker.yml@u/mkoeppe/numpy_1_23_x__scipy_1_9_x
     with:
-      # Reduced list of systems to test: Only those that bring python >= 3.8
-      # Full list at https://github.com/sagemath/sage/blob/develop/.github/workflows/docker.yml
-      # See also https://github.com/sagemath/sage/blob/develop/tox.ini
       tox_system_factors: ${{ needs.build.outputs.systems }}
       tox_packages_factors: >-
         ["minimal-develop",]
-      # Extra packages to install as system packages
-      extra_sage_packages: "liblzma bzip2 libffi libpng python3 ninja_build"
+      # Extra system packages to install. See available packages at
+      # https://github.com/sagemath/sage/tree/develop/build/pkgs
+      # liblzma, bzip2, and libffi are python3 dependencies.
+      extra_sage_packages: "liblzma bzip2 libffi python3 ninja_build"
       # Sage distribution packages to build
       targets: SAGE_CHECK=no SAGE_CHECK_PACKAGES="meson_python" python_build meson_python
       # Standard setting: Test the current beta release of Sage: