Add must usage in coding standards

[alexandre-daubois]

A recurring topic in code PRs is the use of “must” in exception messages. As @chalasr points out in symfony/symfony#59177 (comment), this does not appear to be a decision written into the code standards of the project.

I suggest we add a rule to the standard coding, indicating that “must” should never be used in messages intended for the user. Indeed, it is a feedback I had a few times on some of my PRs. I know that the docs repository tries to ban the use of "must", except in very rare occasions.

What do you think? Discussion is open 🙂

[alexandre-daubois]

Status: Waiting Team Decision

[chalasr]

Although I understand the intent behind this proposal, I'm against adding such a statement as I don't think it is all or nothing.
Docs are mostly about educating, providing guidance about how the framework should be used. On the other hand, code is specification and implementation that state what is strictly expected to make things work.

While it makes sense to use softer wording in guides, I don't think it is wrong to use stronger - more imperative - wording in specifications and the errors/notices that are triggered by implementations and callers.

To me, it doesn't hurt and has the benefit to make things clear.
Also correct me if I'm wrong but looking at other frameworks and languages code, they all seem to use "must" as we do.