Redis [BUG] Empty "save" option is not storred with "config rewrite"

Describe the bug

If save option is set to empty string (""), ie if snapshotting is disabled, then config rewrite command doesn't save save option at all.

Therefore, after restart redis have non-empty save option that matches sample in default redis.conf .

To reproduce

Run redis-server with save option set to "" either in config or with runtime command config set save "". Evaluate config rewrite command. Rewritten config doesn't contain save "" line. After restart, redis has non-empty save option.

# redis-cli -p 6380 config get save
1) "save"
2) "3600 1 300 100 60 10000"

Expected behavior

Config contains save "" option.

Comment From: huangzhw

Like https://github.com/redis/redis/issues/8572. If there is no save, we should emit save "".

Comment From: yossigo

@huangzhw It's not exactly the same issue, #8572 also involves include which is I believe a bigger issue that is not limited to save itself.

Comment From: huangzhw

@yossigo Yes. https://github.com/redis/redis/issues/8572 has more to do. But I think the author just want this.

Comment From: huangzhw

Will we fix this first?

Comment From: JunhuaY

the bug maybe was solved incompletely : when the server is started, and the save option is default, if you issue the " config set save "" " to change the save option, and then issue the “config rewrite” command, the save option change ( from the default to " save "" " ) won't be stored.