Only complete to cabal-version at first line

[StillerHarpo]

The field cabal-version has to be in the first line. So any other
field completion doesn't make sense.

#5115

• I read and followed our AI policy

[dyniec]

Looks good

[VeryMilkyJoe]

Looks good, thank you!
I think I would like a test case for the first line, where a different keyword is already there, so the completer for that field should be triggered instead of the cabal-version one.

[fendor]

Idea is right, I think we want to add the special case for cabal-version in StanzaContext rather than KeyWordContext.

Have you tried your changes, do you feel this behaves better now?

[fendor]

I think this case is impossible, no?

I guess it can only happen if you have library { cabal-version: ... }, but we don't want to offer the completion in this case any way, so the context should likely not use the special case any way.

[StillerHarpo]

No, if I remove this cabal-version is only suggested in empty files

   only suggest cabal-version at start of file with some input:                            FAIL (0.03s)
        plugins/hls-cabal-plugin/test/Completer.hs:94:
        expected: ["cabal-version:"]
         but got: ["category:","package-url:","benchmark","executable"]
        Use -p '$0=="Cabal Plugin Tests.Completer Tests.Basic Completer Tests.only suggest cabal-version at start of file with some input"' to rerun this test only.

[fendor]

I am wondering whether we rather want to say the StanzaContext is FirstLine, so we don't need the special key the for cabal-version. Then cabal-version is just a normal FieldContext, might work out a little better?

[StillerHarpo]

FirstLine is not quite right, because if the cursor is after a key word in the first line we don't want to complete to cabal-version. Should I put it in the StanzaContext and call it CabalVersion I now don't handle all FirstLine contexts as cabal-version

[fendor]

In particular, this case should be impossible (and is). If we made the special case in StanzaContext, this case goes away.