Currently passing in an empty string to parseReplSetSeedList is allowed, but this behavior should likely be disallowed. Introducing the assertion:

uassert(13115, "bad --replSet command line config string (empty)", !replSetString.empty())

has caused failure in some sharding and maintenance JS test suites, where replica sets seem to be initialized with an empty configuration or seed list string.

We should investigate why the sharding and maintenance JSTest suites pass an empty string in these scenarios and determine if this behavior is intentional or a bug in downstream tests. If confirmed as a bug, the tests should be updated to avoid using empty strings, and the assertion should be reintroduced to disallow empty seed lists in parseReplSetSeedList.