caddyfile: Implement variadics for import args placeholders

[WeidiDeng]

imported snippets reflect actual lines in file

fix 5202

[francislavoie]

Oooh, fun. Can you show an example Caddyfile with this?

[mholt]

Very cool, thanks for working on this!

We might need a test case for this, or at least an example that we know works. There's a number of test failures, currently.

[francislavoie]

Hmm. I'm not sure how I feel about the : syntax. Yes obviously it's very Go-like, but I think it reads weird when following a . dot. I think we need to consider some other syntax options.

[WeidiDeng]

Hmm. I'm not sure how I feel about the : syntax. Yes obviously it's very Go-like, but I think it reads weird when following a . dot. I think we need to consider some other syntax options.

Just {args[:]} ?

[francislavoie]

Hmm, maybe. I think if we want to use the [] syntax, we should maybe make {args[0]} work as well (maybe deprecate {args.0}?)

[mholt]

Personally, I'm ok with the : syntax 🤷‍♂️

[rudSarkar]

Is it possible to add a name for each test case like the below example given?

{
	name: "Test duplicate import",
	input: `(t1) {
		abort {args.:}
	}
	:8080 {
		import t1
		import t1 true
	}`,
	errorText: "Caddyfile:6(import t1):2",
},

[mholt]

@rudSarkar That sounds like a good/useful idea. Could be done either in this PR or a later commit.

[rudSarkar]

@mholt I think It will be better to add this on later commit.

[francislavoie]

I worked on cleaning this up -- see recent commit for details.

[mholt]

I think this is looking good!

I might wait for #5275 though, so as to not introduce another conflict. Thanks for working on this both of you 😊

[francislavoie]

I don't think they'll conflict. This only affects the Caddyfile and that PR affects runtime usage of the replacer.

Both do use : in their syntax, but this PR happens during the Caddyfile adapt, on the raw token text, and isn't passed through the replacer (unless a warning happens and an invalid args placeholder falls through to the config, but that's besides the point IMO).

[mholt]

You're right - on closer inspection the files do not overlap. Let's merge this and give it a try!