Lol, having a policy against miscommunication is not going to make it less common.
Edit: note also that there were _two_ harmful misunderstandings here: Person B misunderstood Person A, but Person A also misunderstood Person B’s question. A Code of Conduct is not going to help.
A code of conduct might be able to help, but not by banning rudeness or defensiveness. If a code of conduct succeeds as part of as an effort to develop or maintain a generous culture of patience, assuming good faith, thanking others for their work, and gentleness regarding mistakes, that could short-circuit some of these interactions.
Like when B highlights that this change in suspend behavior was not only documented but '6 months of work', it kinda seems like they were defensive or irritated because they felt like their hard work to implement a useful feature was being discounted. If they felt like that work was recognized, they might have been less defensive about defending the original idea for their future and more curious about why the bug reporter wanted the behavior they wanted.
Same thing for Person A; if they had been less inclined to read Person B's question as critical, they might have explained themselves more completely earlier on.
A code of conduct treated as a rulebook to cite against people would definitely not help, but a skilled moderator pointing to a policy that encourages people to slow down, listen, be curious, or to a shared statement of values that makes people feel relaxed and safe, or to something that evokes pride in their shared participation in the project... that could have gotten this resolved more quickly.
Some projects have maintainers/authors whose kindness, deliberateness, or thoughtfulness seems to flow downstream to later contributors as a norm. Something like a code of conduct could serve in part just to encode that explicitly as a community aspiration.
But yeah you can't just say that being confusing, confused, frustrated, or frustrating is g allowed lol
A code of conduct will only prevent certain language from being used but will not change B's perception of the bug report which I assume involves his own code.
How about a communication center of excellence producing weekly communication quality reports? You won’t be able to access the project page until you have read the latest report and answered three quick questions to verify that you have read the report.
Edit: note also that there were _two_ harmful misunderstandings here: Person B misunderstood Person A, but Person A also misunderstood Person B’s question. A Code of Conduct is not going to help.