Make sure error and status replies emitted by Lua scripts can never have more than a newline, otherwise it is a protocol violation and clients will desync.

src/sds.c

@@ -553,6 +553,29 @@ void sdssplitargs_free(sds *argv, int argc) {
     zfree(argv);
 }
 
+/* Modify the string substituting all the occurrences of the set of
+ * characters specifed in the 'from' string to the corresponding character
+ * in the 'to' array.
+ *
+ * For instance: sdsmapchars(mystring, "ho", "01", 2)
+ * will have the effect of turning the string "hello" into "0ell1".
+ *
+ * The function returns the sds string pointer, that is always the same
+ * as the input pointer since no resize is needed. */
+sds sdsmapchars(sds s, char *from, char *to, size_t setlen) {
+    size_t j, i, l = sdslen(s);
+
+    for (j = 0; j < l; j++) {
+        for (i = 0; i < setlen; i++) {
+            if (s[j] == from[i]) {
+                s[j] = to[i];
+                break;
+            }
+        }
+    }
+    return s;
+}
+
 #ifdef SDS_TEST_MAIN
 #include <stdio.h>
 #include "testhelp.h"