Grails 3.0.1 dialect setting in application.yml does not work

[todoubaba]

environments:
    development:
        dataSource:            
            dialect: ...

[todoubaba]

The configClass in dataSource does not work too.

The workaround is setting them in hibernate section:

hibernate:
    config_class: ...
    dialect: ...

[rennerDa]

I can confirm that your workaround is working :)
The class HibernateDialectDetectorFactoryBean implements the interface GrailsApplicationAware, but at startup inside the method afterPropertiesSet the grailsApplication is null, therefore the config is also null ->
Config config = grailsApplication == null ? null : grailsApplication.getConfig();.

[graemerocher]

Really the dialect setting is better in the hibernate section so I see no reason to fix this, other than updating the docs

[graemerocher]

On second thought no, this is better under the data source as you may need to configure different dialects for multiple data sources

[squarepegsys]

So you cannot declare multiple Hibernate dialects using in the hibernate section?

[graemerocher]

You can, but you also need the ability to declare a different dialect per data source