MDEV-13968 sst fails with "WSREP_SST_OPT_PORT: readonly variable"

Backport from 10.2: 4c2c057 and f7090df

scripts/wsrep_sst_common.sh

@@ -43,7 +43,7 @@ case "$1" in
         else
             readonly WSREP_SST_OPT_HOST_UNESCAPED=${WSREP_SST_OPT_HOST}
         fi
-        readonly WSREP_SST_OPT_PORT=$(echo $WSREP_SST_OPT_ADDR | \
+        readonly WSREP_SST_OPT_ADDR_PORT=$(echo $WSREP_SST_OPT_ADDR | \
                 cut -d ']' -f 2 | cut -s -d ':' -f 2 | cut -d '/' -f 1)
         readonly WSREP_SST_OPT_PATH=${WSREP_SST_OPT_ADDR#*/}
         readonly WSREP_SST_OPT_MODULE=${WSREP_SST_OPT_PATH%%/*}
@@ -126,6 +126,17 @@ done
 readonly WSREP_SST_OPT_BYPASS
 readonly WSREP_SST_OPT_BINLOG
 
+if [ -n "${WSREP_SST_OPT_ADDR_PORT:-}" ]; then
+  if [ -n "${WSREP_SST_OPT_PORT:-}" ]; then
+    if [ "$WSREP_SST_OPT_PORT" != "$WSREP_SST_OPT_ADDR_PORT" ]; then
+      wsrep_log_error "port in --port=$WSREP_SST_OPT_PORT differs from port in --address=$WSREP_SST_OPT_ADDR"
+      exit 2
+    fi
+  else
+    readonly WSREP_SST_OPT_PORT="$WSREP_SST_OPT_ADDR_PORT"
+  fi
+fi
+
 # try to use my_print_defaults, mysql and mysqldump that come with the sources
 # (for MTR suite)
 SCRIPTS_DIR="$(cd $(dirname "$0"); pwd -P)"