[Feature]: in bundless, if cannot resolve, error message should be emitted

[SoonIter]

          By the way, in bundless mode, if cannot resolve, error message should be emitted

Originally posted by @SoonIter in #250 (comment)

[fi3ework]

if cannot resolve, error message should be emitted

In this case, it's because the resolved module is externalized, Rspack won't check if it's available anymore.

Yes, we need to ensure that the emitted files could be resolved. In this case, we overlooked the ⁠index mainFields, which makes this a fixable bug for us. Let's see if there are any paths that Rslib could not detect in the future. If so, we can add a post-check.

[Timeless0911]

getResolve in externals function related.

We can resolve every module when externalized and print a warning if cannot be resolved, but we should benchmark the performance of this.

[Timeless0911]

rslib/packages/core/src/config.ts

Lines 1016 to 1023 in 8a9f9e3

	try {
	resolvedRequest = await resolver(context, resolvedRequest);
	} catch (e) {
	// Do nothing, fallthrough to other external matches.
	logger.debug(
	`Failed to resolve ${resolvedRequest} with resolver`,
	);
	}

@SoonIter should we throw error/warning here if we cannot resolve in bundleless mode?

[SoonIter]

rslib/packages/core/src/config.ts

Lines 1016 to 1023 in 8a9f9e3

	try {
	resolvedRequest = await resolver(context, resolvedRequest);
	} catch (e) {
	// Do nothing, fallthrough to other external matches.
	logger.debug(
	`Failed to resolve ${resolvedRequest} with resolver`,
	);
	}

@SoonIter should we throw error/warning here if we cannot resolve in bundleless mode?

let the bullet in the sky, users would feedback

[Timeless0911]

rslib/packages/core/src/config.ts

Lines 1085 to 1093 in 6f11138

	} catch (e) {
	// catch error when request can not be resolved by resolver
	// e.g. A react component library importing and using 'react' but while not defining
	// it in devDependencies and peerDependencies. Preserve 'react' as-is if so.
	logger.debug(
	`Failed to resolve module ${color.green(`"${request}"`)} from ${color.green(issuer)}. If it's an npm package, consider adding it to dependencies or peerDependencies in package.json to make it externalized.`,
	);
	return request;
	}

Open a new issue if you want to feedback about this issue.