The REPLACE option deletes an existing key with the same name (if any)
and materializes the new one. The default behavior without RESTORE is to
return an error if a key already exists.
(additional commit notes by antirez@gmail.com):
The rdbIsObjectType() macro was not updated when the new RDB object type
of ziplist encoded hashes was added.
As a result RESTORE, that uses rdbLoadObjectType(), failed when a
ziplist encoded hash was loaded.
This does not affected normal RDB loading because in that case we use
the lower-level function rdbLoadType().
The commit also adds a regression test.
