[client-v2] Endpoint with base path causes `<Unreadable error message>`

[Jasper-M]

We have this configuration for the Clickhouse client:

new Client.Builder()
  .addEndpoint("https://our-server:12345/somedatabase?ssl=true&sslmode=STRICT")
  .setUsername(user)
  .setPassword(password)
  .build()

This worked in 0.9.6. After upgrading to 0.9.7 we got these exceptions when trying to launch any kind of query:

com.clickhouse.client.api.ServerException: Code: 0. DB::Exception: <Unreadable error message> (transport error: 404) (queryId= )

Cleaning up the endpoint config to https://our-server:12345 fixed this issue, but it was kind of hard to track down due to the opaque error.

[chernser]

@Jasper-M

My apologies that I have missed to better document this change!

we do not parse URL in the client for properties and base pass.
Endpoint is just host and port.
Additionally you may specify a base path but it is only for cases when proxy handles it.
Database should be set via com.clickhouse.client.api.Client.Builder#setDefaultDatabase

The error is unreadable because it is not standard server output with error code. We know this issue and will fix it.