build/pkgs/sagemath_objects/spkg-install: When ensurepip is not available, fall back to using build --no-isolation

Author: Matthias Koeppe

build/pkgs/sagemath_objects/spkg-install

@@ -19,7 +19,11 @@ export PIP_FIND_LINKS="file://$SAGE_SPKG_WHEELS"
 # (Important because sagemath-objects uses MANIFEST.in for filtering.)
 # Do not install the wheel.
 DIST_DIR="$(mktemp -d)"
-python3 -m build --outdir "$DIST_DIR"/dist . || sdh_die "Failure building sdist and wheel"
+if ! python3 -m build --outdir "$DIST_DIR"/dist .; then
+    # This happens on Debian without python3-venv installed - "ensurepip" is missing
+    echo "Falling back to --no-isolation"
+    python3 -m build --no-isolation --outdir "$DIST_DIR"/dist . || sdh_die "Failure building sdist and wheel"
+fi
 
 wheel=$(cd "$DIST_DIR" && sdh_store_wheel . && echo $wheel)