Clarification: can SignatureHelp.signatures be an empty array?

[mroch]

The interface for SignatureHelp (as of 3.15) says that signatures contains "one or more", but then activeSignature talks about signatures.length === 0.

export interface SignatureHelp {
	/**
	 * One or more signatures.
	 */
	signatures: SignatureInformation[];

	/**
	 * The active signature. If omitted or the value lies outside the
	 * range of `signatures` the value defaults to zero or is ignored if
	 * `signatures.length === 0`. [...]
	 */
	activeSignature?: number;

	[...]
}

It also says "Signature help represents the signature of something callable" which suggests that when the Position is not something callable, the correct response is null, not { signatures: [] }.

If that's the case, I think the docs for activeSignature should not mention signatures.length === 0. Further, why would activeSignature ever be outside the range of signatures? It's confusing that it talks about all these invalid states.

[dbaeumer]

The reason why the spec talks about this is that clients receiving such a result has some reasonable hints what to do if it receives something that where active signature is outside the array.

I do agree if that this can be made more clear. I rephrases it a little.

[vscodebot]

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Happy Coding!