feat: enforcing MISRA compliant Boolean values

[anshgoyalevil]

This PR adds a literal to boolean style check.

bool x = 1;  // Warning: Boolean variable assigned a numeric literal '1'. Consider using 'true' instead.
bool y = 0;  // Warning: Boolean variable assigned a numeric literal '0'. Consider using 'false' instead.

ref: commaai/panda#1876, commaai/panda#2105

[okias]

damn, I'm too slow. Anyway, shouldn't this go into addons/misra.py ? I would guess Rule 23.6

[anshgoyalevil]

Thanks for the suggestion, @okias. I am fairly new to this MISRA thing. I just read the discussion in the thread commaai/panda#1876 and this way looked like what adding the check into ustream meant.

Can you please help identify if that's the right way to do that? Adding a check into upstream without explicitly defining an addon code.

[okias]

In general, a C++ solution like the one you wrote looks better, but I understood it as part of the MISRA plugin—something like this: okias@6b3d84a. The code doesn't detect the initial bool x = 1;, only bool x; x = 1;. This was also my first attempt with cppcheck..

[anshgoyalevil]

Thanks. Now I get the point. I would implement it the MISRA plugin way if this one is rejected by the maintainers.
Can you please review it @danmar

[danmar]

Hi, sorry for the late review. I spontanously feel this might be too "stylistic" in nature. It's not to find "buggy" code, is it? What bugs could it lead to? Normally I like if "style" checkers have a motivation to prevent some possible bugs. For instance; unread variables can for instance indicate an overlook.

I wouldn't normally write bool x=1; myself explicitly.

In my humble opinion it does not violate MISRA 23.6 but it does violate 10.3 and Cppcheck Premium writes a warning about it.

[danmar]

The implementation: I don't have major complaints. It's pretty good. But some test cases is needed and also I think a ticket should be added in trac and the release notes would need to mention the new checker..

[anshgoyalevil]

Thanks for the inputs. This would not help prevent bugs to the code but would help increase readability at some places. I would add the required test cases.

Can you please elaborate that trac thing. How can I file a ticket out there?

[danmar]

This would not help prevent bugs to the code but would help increase readability at some places. I would add the required test cases.

well.. I don't know why anybody would WANT to do this.. but still I don't have a very good feeling about this. This is not the high prio findings users want to see. Could you try to write a checker that looks for "mistakes" somehow? I believe trac has many suggestions as inspiration.

https://trac.cppcheck.net

to get an account on trac you'll need to send a htpasswd hash to me. You can generate a htpasswd hash online, google "htpasswd hash generator"