Major Description
SolrIdentifierValidator accepts shard, collection, cores and alias names following this pattern:
^(?!\\-)[\\._A-Za-z0-9\\-]*$
This accepts an "empty" name. This is easily fixable by changing the * to +. However, it also accepts names such as .., ,__--- etc. Do we not want to require collection names to have a letter/digit identifier in them? Something like the following pattern:
^(\\.)?[a-zA-Z0-9]+[\\._\\-a-zA-Z0-9]*$
That pattern requires the name to start with an optional . followed by a series of letters/digits followed by the rest of the allowed characters.
What do you think?