user guide should document new fields with the version of Cabal they appeared in

[bos]

(Imported from Trac #508, reported by @dcoutts on 2009-02-25)

It would be nice if the user guide specified in which Cabal version a field was first introduced. This would help package authors work out compatibility.

With this documented we should also check that cabal check gives the same advice. That is if a package uses a field that is new in version 1.2 say, that cabal check warns if the cabal-version: >=x.y number is not high enough. It should only be a warning not an error because older Cabal versions only warn about unknown fields.

While we're at it, we should document in the user guide that unknown fields give a warning, but should not cause a parse error. This lets people use new non-essential informational fields without having to absolutely require a later Cabal version. Probably a section on version compatibility is wanted.

[tibbe]

Closing as there's been no activity in years.

We're cleaning up the bug tracker to make it useful again and are thus closing bugs that haven't seen any activity in a long time. Please re-open (or file a new bug) if the problem reappears.