The original issue was raised at https://github.com/spring-projects/spring-boot/issues/14903 for Spring Boot 1.5.13.RELEASE, but mentioned, that the issue must be created for springframework.
Provided a custom auto configuration definition in META-INF/spring.factories of the following form for Spring Boot:
Spring failed to load the configuration class " FQNClassB", because no whitespace trimming was done.
As a java identifier can not have got any whitespace in it, whitespace trimming should be applied for a class token by SpringFactoriesLoader.
In my opinion this would make a definition more robust, as whitespace mistakes are harder to review and this might be an unexpected behaviour from user perspective as whitespace is expected to be ignored.