CMAKE option warnings and errors not consistent (or documented)

[LtdSauce]

I noticed that not all cmake warnings are turned into errors when the variable WARNING_MESSAGE is set to SEND_ERROR, hence WARNINGS_AS_ERRORS enabled.

For example a missing clang-tidy will produce an error if the corresponding option is set (see StaticAnalyzer.cmake:32).
On the other hand a missing Sanitizer is always producing a warning (see Sanitizers.cmake:27).
Same goes for a missing ccache executable (see cache.cmake:29).

I cannot find any explantation why those are treated different, which kind of confuses me.

Would it be possible to add comments why some do not use the WARNING_MESSAGE variable, if that had been done on purpose?
Which seems the case at least for clang-tidy if i correctly understand #30.

[LtdSauce]

Maybe something like ENABLE_IF_<tool> or OPTIONAL_ENABLE_<tool> could be used for those to make it explicit, that it is always a warning and never an error? (Providing that to every option would enable the user to specify what option is optional and what is mandatory)

[aminya]

WARNINGS_AS_ERRORS is used for the tools that analyze the code semantically. The compiler itself, clang-tidy, cppcheck and any other static analyzer.

[LtdSauce]

Ah i see! That makes sense.

Would you consider this to be common knowledge (that i didn't have) or is it worth adding a comment to the WARNINGS_AS_ERRORS option?

The comment now only says, that it turns Compiler warnings into errors. But, apparently it does more?

[aminya]

Yes, we should add this to the docs.

P.S: I don't personally use WARNINGS_AS_ERRORS because I don't need an external force for addressing the warnings. 😉

[aminya]

@LtdSauce are you interested in improving the docs here?

[LtdSauce]

If i find the time i could open a PR.

I would suggest something like:

"Turns compiler and static code analyzer warnings into errors. This also effects cmake warnings related to those."

[aminya]

Thanks! I added the commit