build/bin/sage-bootstrap-python: Prefer a Python that provides ssl wi…

…th SNI

build/bin/sage-bootstrap-python

@@ -40,7 +40,19 @@ if [ "$LC_ALL" = "C" -o "$LANG" = "C" -o "$LC_CTYPE" = "C" ]; then
     export LANG
 fi
 
-PYTHONS="python python3 python3.8 python3.7 python2.7 python3.6 python2"
+PYTHONS="python python3 python3.10 python3.9 python3.8 python3.7 python2.7 python3.6 python2"
+# Trac #32405: Prefer a Python that provides ssl with SNI, which allows developers
+# to download from upstream URLs (configure --enable-download-from-upstream-url),
+# in particular from PyPI, which requires SNI.
+for PY in $PYTHONS; do
+    PYTHON="$(PATH="$SAGE_ORIG_PATH" command -v $PY)"
+    if [ -n "$PYTHON" ]; then
+        if "$PYTHON" -c "import argparse; import urllib; from hashlib import sha1; from ssl import HAS_SNI; assert HAS_SNI; from os import listdir; listdir(\"$(pwd)\");" 2>/dev/null; then
+            exec "$PYTHON" "$@"
+        fi
+    fi
+done
+# Second round, no ssl/SNI test.
 for PY in $PYTHONS; do
     PYTHON="$(PATH="$SAGE_ORIG_PATH" command -v $PY)"
     if [ -n "$PYTHON" ]; then