CLI `validate` command hates long lines

[kubukoz]

When you run validate, build or any other command that validates your model, if the sourceLocation in the validation events points to a compact JSON file (say, one of the AWS specs), the CLI will output basically a bunch of blank lines which will look terrible in the terminal.

Even with a smaller JSON file, like:

{"smithy":"2.0","shapes":{"example.weather#Home":{"type":"operation","input":{"target":"smithy.api#Unit"},"output":{"target":"smithy.api#Unit"},"traits":{"smithy.api#http":{"method":"GET","uri":"/"}}},"example.weather#Weather":{"type":"service","operations":[{"target":"example.weather#Home"}]}}}

Running validate yields:

which doesn't seem very useful with the source location.

Note: it's entirely possible that I've already reported this, because I remember writing about it, but I can't find any issue for this.

[kubukoz]

Apparently, it affects long lines in IDL files too:

$version: "2"

namespace example.weather

enum A {
                                                                                        result = "res"
}

although I can't imagine this happening often for someone using a formatter.

[JordonPhillips]

I'm not sure there's a great way to display this. We could wrap the line, but I don't think that would look great either. We could also truncate from the beginning, but that would be even more confusing I think. I'll check with the rest of the team to see what they think about the options when everybody is back from the holiday vacations.

At the very least though, the red arrow shouldn't go past the truncation marker.

[kubukoz]

I'd look at how other languages do it. In Scala, for example, the beginning gets truncated but you also see the line/column numbers, allowing you to find the exact spot: