Support reporting multiple errors and/or warnings

[sharwell]

The current implementation throws an exception the first time an issue is detected, and only supports reporting a single issue. It would be helpful to report all issues instead.

[sharwell]

@nguerrera I'm particularly interested in what you would feel is "useful" output from this library.

Should it issue "warnings" and "errors" with particular IDs (like a compiler or the new Roslyn diagnostics)? Or perhaps some other report format?

My goal is to use this tool during the testing phase, and have the output be such that new contributors to a project can both understand why their change is not compatible and where they can find additional information on how to proceed.

[nguerrera]

I think a flat list of compiler-like errors and warnings is ideal. I wouldn't necessarily bother with numeric IDs. My experience is that they just force me to search the internet where a decent name would tell me more. I'm biased by both my experience developing FxCop and our internal compat tool which both use PascalCase identifiers like MembersMustNotBeRemoved. (FxCop eventually got warning numbers as they were needed at the time for integration with VS help and that led to people sending me email like "Having problems with CA1234", which really made talking about them harder for no real benefit IMHO. YMMV.

[sharwell]

It sure would be nice to see a list of those identifiers from the compatibility tool. 😉 Would save time making it available for everyone working on versioning .NET code.