Add support for configuring the Redis database using spring.data.redis.url

[quaff]

Fix GH-43810

[wilkinsona]

Thanks for the PR, @quaff. A couple of things:

1. Could you please rebase this on top of the head of main to address the conflicts?
2. Did you consider making getDatabase() of the Sentinel instance returned by PropertiesRedisConnectionDetails use the database from the URL? I am in two minds as to whether that's the right thing to do.

[quaff]

1. Could you please rebase this on top of the head of main to address the conflicts?

done.

2. Did you consider making getDatabase() of the Sentinel instance returned by PropertiesRedisConnectionDetails use the database from the URL? I am in two minds as to whether that's the right thing to do.

I think sentinel should respect database in url also, I appended another commit, feel free to squash or drop it.

[wilkinsona]

Thanks very much, @quaff.

[wilkinsona]

Unfortunately, I've just reverted this as, while updating the release notes, I realised that the implementation's incorrect.

The property's documentation states that the URL overrides the database (as it should do) but the implementation doesn't do so. Unlike username, password, etc that are completely overridden by the URL, database has been implemented such that the property is used as a fallback when the URL doesn't have a database. I don't think this is right. Instead, it should use the default database which is 0.

@quaff, can you please update your proposal so that ConnectionInfo defaults to 0 for its database value when the URL does not specify the database. The database value from ConnectionInfo should then always be used when the URL has been configured. This will align the behaviour of the database property with that of the hostname, port, username, and password properties when the URL property has been set.

[quaff]

@wilkinsona Good point, I updated the PR.

[wilkinsona]

Thanks, @quaff.