Test pip editable install with meson

.github/workflows/ci-meson.yml

@@ -16,14 +16,28 @@ concurrency:
 
 jobs:
   test:
-    name: Conda (${{ matrix.os }}, Python ${{ matrix.python }})
+    name: Conda (${{ matrix.os }}, Python ${{ matrix.python }}${{ matrix.editable && ', editable' || '' }})
     runs-on: ${{ matrix.os }}-latest
 
     strategy:
       fail-fast: false
       matrix:
         os: [ubuntu]
         python: ['3.11', '3.12']
+        editable: [false, true]
+        is-pull-request:
+          - ${{ github.event_name == 'pull_request' }}
+          # trick from https://github.com/orgs/community/discussions/26253#discussioncomment-6745038
+          # in PR, only run the combinations listed below; otherwise, run all combinations
+        exclude:
+          - is-pull-request: true
+        include:
+          - os: ubuntu
+            python: 3.11
+            editable: false
+          - os: ubuntu
+            python: 3.12
+            editable: true
 
     steps:
       - uses: actions/checkout@v4
@@ -70,7 +84,7 @@ jobs:
           export CC="ccache $CC"
           export CXX="ccache $CXX"
           # Use --no-deps and pip check below to verify that all necessary dependencies are installed via conda
-          pip install --no-build-isolation --no-deps --config-settings=builddir=builddir . -v
+          pip install --no-build-isolation --no-deps --config-settings=builddir=builddir ${{ matrix.editable && '--editable' || '' }} . -v
 
       - name: Check update-meson
         # this step must be after build, because meson.build creates a number of __init__.py files
@@ -93,12 +107,14 @@ jobs:
         shell: bash -l {0}
         run: |
           # We don't install sage_setup, so don't try to test it
-          rm -R ./src/sage_setup/
+          # If editable then deleting the directory will cause sage to detect rebuild, which will cause ninja to fail
+          # so we don't delete the directory in this case
+          ${{ matrix.editable && 'true' || 'rm -R ./src/sage_setup/' }}
           ./sage -t --all -p4 --format github
 
       - name: Upload log
         uses: actions/[email protected]
         if: failure()
         with:
-          name: ${{ runner.os }}-meson-${{ matrix.python }}-log
+          name: ${{ runner.os }}-meson-${{ matrix.python }}${{ matrix.editable && '-editable' || '' }}-log
           path: builddir/meson-logs/