To make it easier for developers to test out pull requests which bump
the realm schema version, realm files are now stored with the schema
version in the filename.
Note that this means any changes made to a newer version will not be
applied to previous ones.
Was originally relying on the fact that this would be triggered due to a
null `LastOnlineUpdate`, but wouldn't cover the case of beatmaps with no
`OnlineID`.
As far as I can tell all accesses are safe due to update thread
guarantees. The only weird one may be async writes during a
`BlockAllOperations`, but the `Compact` loop should handle this quite
amicably.
After a `BlockAllOperations`, the restoration of the `updateRealm`
instance is not instance. It is posted to a `SynchronizationContext`.
The assertion which has been removed in this commit was assuming it
would always be an immediate operation.
To ensure this works as expected, I've tracked the initialised state via
a new `bool`.
```csharp
System.TimeoutException : Attempting to block for migration took too long.
1) Host threw exception System.AggregateException: One or more errors occurred. (: )
---> NUnit.Framework.AssertionException: :
at osu.Framework.Logging.ThrowingTraceListener.Fail(String message1, String message2)
at System.Diagnostics.TraceInternal.Fail(String message, String detailMessage)
at System.Diagnostics.TraceInternal.TraceProvider.Fail(String message, String detailMessage)
at System.Diagnostics.Debug.Fail(String message, String detailMessage)
at osu.Game.Database.RealmAccess.BlockAllOperations() in /opt/buildagent/work/ecd860037212ac52/osu.Game/Database/RealmAccess.cs:line 813
at osu.Game.OsuGameBase.<>c__DisplayClass108_1.<Migrate>b__0() in /opt/buildagent/work/ecd860037212ac52/osu.Game/OsuGameBase.cs:line 449
at osu.Framework.Threading.ScheduledDelegate.RunTaskInternal()
at osu.Framework.Threading.Scheduler.Update()
at osu.Framework.Graphics.Drawable.UpdateSubTree()
at osu.Framework.Graphics.Containers.CompositeDrawable.UpdateSubTree()
```
https://teamcity.ppy.sh/buildConfiguration/Osu_Build/322?hideProblemsFromDependencies=false&hideTestsFromDependencies=false&expandBuildTestsSection=true
