When an experimental feature graduates from being experimental, we want
to continue allow the old "--experimental-features=..." option to work,
in case some user's configuration uses it - just do nothing. The way
we do it is to map in db::experimental_features_t::map() the feature's
name to the UNUSED value - this way the feature's name is accepted, but
doesn't change anything.
When the CDC feature graduated from being experimental, a new bit
UNUSED_CDC was introduced to do the same thing. This separate bit was
not actually necessary - if we ever check for UNUSED_CDC bit anywhere
in the code it means the flag isn't actually unused ;-) And we don't
check it.
So simplify the code by conflating UNUSED_CDC into UNUSED.
This will also make it easy to build from db::experimental_features_t::map()
a list of current experimental features - now it will simply be those that
do not map to UNUSED.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20211013105107.123544-1-nyh@scylladb.com>
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