add script to perform mas migration compatibility check

abra.sh

@@ -19,6 +19,45 @@ ensure_mas_database () {
     fi
 }
 
+# Local helper: fetch homeserver.yaml from app, push to mas, then syn2mas check + dry-run.
+prepare_mas_migration () {
+    local hs_local syn_cfg
+
+    syn_cfg=/tmp/homeserver.yaml
+
+    cleanup_prepare_mas_migration() {
+        rm -f "homeserver.yaml"
+    }
+    trap cleanup_prepare_mas_migration EXIT
+
+    echo "Fetching /data/homeserver.yaml from app to homeserver.yaml (abra app run … cat)..."
+    if ! abra app run -t "$DOMAIN" app cat /data/homeserver.yaml > "homeserver.yaml"
+    then
+        return 1
+    fi
+    if [ ! -s "homeserver.yaml" ]; then
+        echo "Error: fetched homeserver.yaml is empty." >&2
+        return 1
+    fi
+
+    echo "Copying into mas:/tmp"
+    abra app cp -C "$DOMAIN" "homeserver.yaml" "mas:/tmp" || return 1
+
+    echo "Running mas-cli syn2mas check..."
+    abra app run -t "$DOMAIN" mas -- mas-cli syn2mas check \
+        --config /etc/mas/config.yaml \
+        --synapse-config "$syn_cfg" || return 1
+
+    echo "Running mas-cli syn2mas migrate --dry-run..."
+    abra app run -t "$DOMAIN" mas -- mas-cli syn2mas migrate \
+        --config /etc/mas/config.yaml \
+        --synapse-config "$syn_cfg" \
+        --dry-run || return 1
+
+    # trap - EXIT
+    # cleanup_prepare_mas_migration
+}
+
 set_admin () {
     admin=akadmin
     if [ -n "$1" ]