Add a failure analyzer for Hibernate bootstrap failure

I'm trying to make my application's configuration as foolproof as possible by failing as soon as missing properties are detected. My app has two DataSources so I followed the Configure Two DataSources how-to. This works nicely, but gets confusing if the properties with given prefix aren't there (this would happen if the production .yml file was missing or didn't contain the expected DB credentials). In a JPA application this causes:

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1568)
(...snip...)
        at demo.Application.main(Application.java:14)
Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
        at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:104)
        at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:71)
(...snip...)
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:842)
        at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60)
        at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:341)
        at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1627)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1564)
        ... 14 more

I'd expect something more precise like "Couldn't initialise DataSource with prefix=datasource.secondary; check your config!".

I tried it with a JDBC starter too and it... quietly succeeds, initializing the DataSource with nulls - not sure if it's a different underlying issue.

Haven't done more investigation, may try to debug to narrow it down a bit if needed. Submitted repros for both problems to spring-boot-issues.