Painless: improve error message when parameter must be a constant but isn't

[nik9000]

Now the error message is:

"all arguments must be constant but the [2] argument isn't

That isn't really even English. I mean, it tells you where to look and we don't have any better ideas given the infrastructure we have, but we do need to make it better.

[elasticmachine]

Pinging @elastic/es-core-infra (Team:Core/Infra)

[stu-elastic]

Yes this message should be better. @nik9000 can you provide a brief script illustrating the problem?

[nik9000]

In a runtime field if you do something like:

String a = 'a';
String b = 'b';
grok(a + b);

Which, I think, will reply with something like: "all arguments must be constant but the [1] argument isn't"

[aileenpalafox]

Hi, can I check this out? First time contributing

[andrevpessanha]

Hi @nik9000, i opened a PR to solve this issue and since this is my first contribution, i'd be really glad if you could give me some feedback.

[andrevpessanha]

Hi @nik9000, could you tell me what do you think of these new error messages? I had mapped four occurrences of this type of error, but please let me know if i forgot to update any other messages.

[Kxrr]

Could I jump on this issue?

I'm going to optimize the error message to:

All arguments of the [<methodName>] method must be constants, 
but the argument [<argumentName>] is not

[stu-elastic]

@Kxrr, That'd be a good message

[Kxrr]

Hi @stu-elastic, could you please review my changes in #82638