Trac #33789: sage-dist-helpers (sdh_pip_install): Change default to -…

…-build-isolation

... hence, provisioning the build environment for each package from the
stored wheels.

This gets us another step closer to using modern Python packaging
infrastructure. It will make the build process more robust because it
avoids concurrent read and write access to `site-packages`.

If it fails, it falls back the old behavior (`--no-build-isolation`) and
issues a warning.

URL: https://trac.sagemath.org/33789
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): John Palmieri

build/bin/sage-dist-helpers

@@ -56,11 +56,11 @@
 #    be given as arguments.  If $SAGE_DESTDIR is not set then the command is
 #    run with $SAGE_SUDO, if set.
 #
-# - sdh_pip_install [--no-deps] [--build-isolation] [...]
+# - sdh_pip_install [--no-deps] [--build-isolation] [--no-build-isolation] [...]
 #
 #    Builds a wheel using `pip wheel` with the given options [...], then installs
-#    the wheel.  Unless the special option --build-isolation is given,
-#    the wheel is built using the option --no-build-isolation.
+#    the wheel.  Unless the special option --no-build-isolation is given,
+#    the wheel is built using build isolation.
 #    If the special option --no-deps is given, it is passed to pip install.
 #    If $SAGE_DESTDIR is not set then the command is run with $SAGE_SUDO, if
 #    set.
@@ -243,16 +243,20 @@ sdh_pip_install() {
     rm -f dist/*.whl
     install_options=""
     # pip has --no-build-isolation but no flag that turns the default back on...
-    build_isolation_option="--no-build-isolation --no-binary :all:"
+    build_isolation_option="--find-links=$SAGE_SPKG_WHEELS"
     while [ $# -gt 0 ]; do
         case "$1" in
             --build-isolation)
-                # If a package requests build isolation, we allow it to provision
+                # Our default after #33789 (Sage 9.7): We allow the package to provision
                 # its build environment using the stored wheels.
-                # We pass --find-links and remove the --no-binary option.
+                # We pass --find-links.
                 # The SPKG needs to declare "setuptools_wheel" as a dependency.
                 build_isolation_option="--find-links=$SAGE_SPKG_WHEELS"
                 ;;
+            --no-build-isolation)
+                # Use --no-binary, so that no wheels from caches are used.
+                build_isolation_option="--no-build-isolation --no-binary :all:"
+                ;;
             --no-deps)
                 install_options="$install_options $1"
                 ;;
@@ -262,9 +266,25 @@ sdh_pip_install() {
         esac
         shift
     done
-    python3 -m pip wheel --wheel-dir=dist --verbose --no-deps --no-index --isolated --ignore-requires-python $build_isolation_option "$@" || \
-        sdh_die "Error building a wheel for $PKG_NAME"
-
+    if python3 -m pip wheel --wheel-dir=dist --verbose --no-deps --no-index --isolated --ignore-requires-python $build_isolation_option "$@"; then
+        : # successful
+    else
+        case $build_isolation_option in
+            *--no-build-isolation*)
+                sdh_die "Error building a wheel for $PKG_NAME"
+                ;;
+            *)
+                echo >&2 "Warning: building with \"python3 -m pip wheel --wheel-dir=dist --verbose --no-deps --no-index --isolated --ignore-requires-python $build_isolation_option\" failed."
+                build_isolation_option="--no-build-isolation --no-binary :all:"
+                echo >&2 "Retrying with \"python3 -m pip wheel --wheel-dir=dist --verbose --no-deps --no-index --isolated --ignore-requires-python $build_isolation_option\"."
+                if python3 -m pip wheel --wheel-dir=dist --verbose --no-deps --no-index --isolated --ignore-requires-python $build_isolation_option "$@"; then
+                    echo >&2 "Warning: Wheel building needed to use \"$build_isolation_option\" to succeed. This means that a dependencies file in build/pkgs/ needs to be updated. Please report this to sage-devel@googlegroups.com, including the build log of this package."
+                else
+                    sdh_die "Error building a wheel for $PKG_NAME"
+                fi
+                ;;
+        esac
+    fi
     sdh_store_and_pip_install_wheel $install_options .
 }
 

build/pkgs/tomli/spkg-install.in

@@ -1,4 +1,7 @@
 cd src
 # tomli's build system, flit_core, has a runtime dependency on tomli.
+# Hence we make the uninstalled tomli sources available during the installation
+# and disable build isolation -- which would require a tomli wheel to
+# be available for setting up the build environment.
 export PYTHONPATH="$(pwd)"
-sdh_pip_install .
+sdh_pip_install --no-build-isolation .