Stuck clang-tidy check review, legal issues?

Clang Frontend
1

Hi.

I have the following Differential
https://reviews.llvm.org/D36836

SUMMARY
...
This check checks function Cognitive Complexity metric, and flags
the functions with Cognitive Complexity exceeding the configured limit.
The default limit is `25`, same as in 'upstream'.

The metric is implemented as per [[ https://www.sonarsource.com/docs/

CognitiveComplexity.pdf | COGNITIVE COMPLEXITY by SonarSource ]] specification
version 1.2 (19 April 2017), with two notable exceptions:

* `preprocessor conditionals` (`#ifdef`, `#if`, `#elif`, `#else`, `#endif`)
   are not accounted for.
   Could be done. Currently, upstream does not account for them either.
* `each method in a recursion cycle` is not accounted for.
   It can't be fully implemented, because cross-translational-unit analysis
   would be needed, which is not possible in clang-tidy.
   Thus, at least right now, i completely avoided implementing it.

As you can see, the implementation is based on a specification.

That Differential was created on 17 Aug, so ~50 days ago. In all this time,
there has been basically no feedback. Mid-September, thanks to Aaron Ballman,
the first review was done by Jonas Toth. Thanks to both of them!

After that, the code owner, Alexander Kornienko, has left a short message
questioning the legal status of that code
https://reviews.llvm.org/D36836#877636

In my reply https://reviews.llvm.org/D36836#877642 i have shared the email
exchange which i believe supports my view that it is okay to have this in
LLVM. Since then, there has been no feedback.

Questions that i'd love to get addressed by this mail
* Am i doing something wrong?
* Am i, as not a lawyer, wrong in my view about the code status?
* Can somebody please review that code? :slight_smile:

Roman.

2

Hi.

I have the following Differential
⚙ D36836 [clang-tidy] Implement readability-function-cognitive-complexity check

SUMMARY
...
This check checks function Cognitive Complexity metric, and flags
the functions with Cognitive Complexity exceeding the configured limit.
The default limit is `25`, same as in 'upstream'.

The metric is implemented as per [[ https://www.sonarsource.com/docs/

CognitiveComplexity.pdf | COGNITIVE COMPLEXITY by SonarSource ]] specification
version 1.2 (19 April 2017), with two notable exceptions:

* `preprocessor conditionals` (`#ifdef`, `#if`, `#elif`, `#else`, `#endif`)
   are not accounted for.
   Could be done. Currently, upstream does not account for them either.
* `each method in a recursion cycle` is not accounted for.
   It can't be fully implemented, because cross-translational-unit analysis
   would be needed, which is not possible in clang-tidy.
   Thus, at least right now, i completely avoided implementing it.

As you can see, the implementation is based on a specification.

That Differential was created on 17 Aug, so ~50 days ago. In all this time,
there has been basically no feedback. Mid-September, thanks to Aaron Ballman,
the first review was done by Jonas Toth. Thanks to both of them!

After that, the code owner, Alexander Kornienko, has left a short message
questioning the legal status of that code
⚙ D36836 [clang-tidy] Implement readability-function-cognitive-complexity check

In my reply ⚙ D36836 [clang-tidy] Implement readability-function-cognitive-complexity check i have shared the email
exchange which i believe supports my view that it is okay to have this in
LLVM. Since then, there has been no feedback.

I provided feedback on 9/28 that basically suggests we should add
something to our license files. I think the email is sufficient to
demonstrate we're likely in the clear, but an email as part of a
review chain is not sufficient by itself -- we need to capture that
information elsewhere which people downloading the source will have
access to.

Questions that i'd love to get addressed by this mail
* Am i doing something wrong?

No.

* Am i, as not a lawyer, wrong in my view about the code status?

Not to my knowledge, but I'm also not a lawyer.

* Can somebody please review that code? :slight_smile:

When dealing with obscure licensing questions, everything takes longer
than normal because we need to be careful to get it right. When I
worked on the licensing stuff with the CERT checkers I ran into
similar delays. My recommendation is to work on the license file stuff
that I mentioned in the review and then re-ping once that's completed.
It may take a few tries to get it right because we have *some*
precedent, but this is far from a regular occurrence.

~Aaron