Re: [Libguestfs] [PATCH 4/4] mltools: JSON: unify JSON_parser type with JSON.json_t.

22 Aug 2018

      On Monday, 20 August 2018 18:02:06 CEST Richard W.M. Jones wrote:
...
-  } else
-    rv = Val_none;
+  }
+  else {
+    /* Previously we had a special JSON_parser_null value we could
+     * use here, making the returned type (sort of) an option.
+     * This is a best effort which is better than crashing /
+     * throwing an error.
+     */
+    rv = caml_alloc (1, JSON_STRING_TAG);
+    v = caml_copy_string ("");
+    Store_field (rv, 0, v);
+  }
NACK, this is not correct.  null is a proper type of value in JSON, and
thus JSON.json_t must represent it as well.

This is even used in other parts, for example the check of backing
files of disks (see guestfs_impl_disk_has_backing_file).

-- 
Pino Toscano