Make LineFormatter::formatException protected

[Y. Wayne Huang]

Not sure if this has been discussed before and perhaps the cons outweigh the pros, but at present, it is not possible to create a custom line formatter that extends LineFormatter without reimplementing a lot of business logic because formatException is private. It seems this might be an area where it is desirable to add custom handling via a custom line formatter. Some libraries or frameworks have custom base exceptions containing additional library-/framework-specific data that for the general case might be too verbose to include in the exception message, but would be useful for some application-specific logging purpose.

One example is Doctrine\DBAL\Exception\DriverException, which contains the executed query along with parameters, but does not include the query or parameters in the exception message itself.

[Jordi Boggiano]

IMO you can override normalizeException if you want to do this. Because if I open up formatException then we also have to open up stacktracesParser, etc. I'd rather keep it how it is.