Repeated config arguments results in a confusing error

[nwf]

I am unsure if this belongs here or over in https://github.com/yargs/yargs instead, but I think it's mostly an issue here in the parser.

In any case, I went and wrote a little CLI tool using nodejs and yargs and in particular its .config() mechanism; so far, so good. However, if I pass --config more than once (e.g. --config a.json --config b.json), it dies with the help message and the confusing report Invalid JSON config file: [ './a.json', './b.json' ]. A little brute force shows that that report arises from

yargs-parser/lib/yargs-parser.ts

Line 688 in 217aa62

else if (argv[configKey]) error = Error(__('Invalid JSON config file: %s', configPath))

but is, ultimately, because the call to mixin.resolve on

yargs-parser/lib/yargs-parser.ts

Line 666 in 217aa62

const resolvedConfigPath = mixin.resolve(mixin.cwd(), configPath)

is, by default, a call to path.resolve (owing to

yargs-parser/lib/index.ts

Line 38 in 90f970a

resolve,

) and path.resolve balks if not given a string as its second argument.

At the very least the error could be more informative (perhaps, "configuration options may be given at most once"), but because it's possible to have multiple .config() directives applied to yargs, and so the machinery tolerates the notion of multiple config files in general, I would prefer to wrap the entirety of

yargs-parser/lib/yargs-parser.ts

Lines 664 to 689 in 217aa62

	try {
	let config = null
	const resolvedConfigPath = mixin.resolve(mixin.cwd(), configPath)
	const resolveConfig = flags.configs[configKey]
	if (typeof resolveConfig === 'function') {
	try {
	config = resolveConfig(resolvedConfigPath)
	} catch (e) {
	config = e
	}
	if (config instanceof Error) {
	error = config
	return
	}
	} else {
	config = mixin.require(resolvedConfigPath)
	}
	setConfigObject(config)
	} catch (ex: any) {
	// Deno will receive a PermissionDenied error if an attempt is
	// made to load config without the --allow-read flag:
	if (ex.name === 'PermissionDenied') error = ex
	else if (argv[configKey]) error = Error(__('Invalid JSON config file: %s', configPath))
	}

in a loop to handle the case that configPath is an array.

[Velewele]

Tt