Merge pull request #12631 from webpack/feature/resolve-hint

add some better hints when resolving fails

lib/NormalModuleFactory.js

@@ -750,35 +750,148 @@ class NormalModuleFactory extends ModuleFactory {
 			resolveContext,
 			(err, resolvedResource, resolvedResourceResolveData) => {
 				if (err) {
-					if (resolver.options.fullySpecified) {
-						resolver
-							.withOptions({
-								fullySpecified: false
-							})
-							.resolve(
-								contextInfo,
-								context,
-								unresolvedResource,
-								resolveContext,
-								(err2, resolvedResource) => {
-									if (!err2 && resolvedResource) {
-										const resource = parseResource(
-											resolvedResource
-										).path.replace(/^.*[\\/]/, "");
-										err.message += `
-Did you mean '${resource}'?
+					return this._resolveResourceErrorHints(
+						err,
+						contextInfo,
+						context,
+						unresolvedResource,
+						resolver,
+						resolveContext,
+						(err2, hints) => {
+							if (err2) {
+								err.message += `
+An fatal error happened during resolving additional hints for this error: ${err2.message}`;
+								err.stack += `
+
+An fatal error happened during resolving additional hints for this error:
+${err2.stack}`;
+								return callback(err);
+							}
+							if (hints && hints.length > 0) {
+								err.message += `
+${hints.join("\n\n")}`;
+							}
+							callback(err);
+						}
+					);
+				}
+				callback(err, resolvedResource, resolvedResourceResolveData);
+			}
+		);
+	}
+
+	_resolveResourceErrorHints(
+		error,
+		contextInfo,
+		context,
+		unresolvedResource,
+		resolver,
+		resolveContext,
+		callback
+	) {
+		asyncLib.parallel(
+			[
+				callback => {
+					if (!resolver.options.fullySpecified) return callback();
+					resolver
+						.withOptions({
+							fullySpecified: false
+						})
+						.resolve(
+							contextInfo,
+							context,
+							unresolvedResource,
+							resolveContext,
+							(err, resolvedResource) => {
+								if (!err && resolvedResource) {
+									const resource = parseResource(resolvedResource).path.replace(
+										/^.*[\\/]/,
+										""
+									);
+									return callback(
+										null,
+										`Did you mean '${resource}'?
 BREAKING CHANGE: The request '${unresolvedResource}' failed to resolve only because it was resolved as fully specified
 (probably because the origin is a '*.mjs' file or a '*.js' file where the package.json contains '"type": "module"').
 The extension in the request is mandatory for it to be fully specified.
-Add the extension to the request.`;
-									}
-									callback(err);
+Add the extension to the request.`
+									);
 								}
-							);
-						return;
+								callback();
+							}
+						);
+				},
+				callback => {
+					if (!resolver.options.enforceExtension) return callback();
+					resolver
+						.withOptions({
+							enforceExtension: false,
+							extensions: []
+						})
+						.resolve(
+							contextInfo,
+							context,
+							unresolvedResource,
+							resolveContext,
+							(err, resolvedResource) => {
+								if (!err && resolvedResource) {
+									let hint = "";
+									const match = /(\.[^.]+)(\?|$)/.exec(unresolvedResource);
+									if (match) {
+										const fixedRequest = unresolvedResource.replace(
+											/(\.[^.]+)(\?|$)/,
+											"$2"
+										);
+										if (resolver.options.extensions.has(match[1])) {
+											hint = `Did you mean '${fixedRequest}'?`;
+										} else {
+											hint = `Did you mean '${fixedRequest}'? Also note that '${match[1]}' is not in 'resolve.extensions' yet and need to be added for this to work?`;
+										}
+									} else {
+										hint = `Did you mean to omit the extension or to remove 'resolve.enforceExtension'?`;
+									}
+									return callback(
+										null,
+										`The request '${unresolvedResource}' failed to resolve only because 'resolve.enforceExtension' was specified.
+${hint}
+Including the extension in the request is no longer possible. Did you mean to enforce including the extension in requests with 'resolve.extensions: []' instead?`
+									);
+								}
+								callback();
+							}
+						);
+				},
+				callback => {
+					if (
+						/^\.\.?\//.test(unresolvedResource) ||
+						resolver.options.preferRelative
+					) {
+						return callback();
 					}
+					resolver.resolve(
+						contextInfo,
+						context,
+						`./${unresolvedResource}`,
+						resolveContext,
+						(err, resolvedResource) => {
+							if (err || !resolvedResource) return callback();
+							const moduleDirectories = resolver.options.modules
+								.map(m => (Array.isArray(m) ? m.join(", ") : m))
+								.join(", ");
+							callback(
+								null,
+								`Did you mean './${unresolvedResource}'?
+Requests that should resolve in the current directory need to start with './'.
+Requests that start with a name are treated as module requests and resolve within module directories (${moduleDirectories}).
+If changing the source code is not an option there is also a resolve options called 'preferRelative' which tries to resolve these kind of requests in the current directory too.`
+							);
+						}
+					);
 				}
-				callback(err, resolvedResource, resolvedResourceResolveData);
+			],
+			(err, hints) => {
+				if (err) return callback(err);
+				callback(null, hints.filter(Boolean));
 			}
 		);
 	}

test/cases/errors/module-request/dependency.js

@@ -0,0 +1 @@
+export {};

test/cases/errors/module-request/errors.js

@@ -0,0 +1,3 @@
+module.exports = [
+	[/Can't resolve 'dependency\.js'/, /Did you mean '\.\/dependency\.js'\?/]
+];

test/cases/errors/module-request/index.js

@@ -0,0 +1,5 @@
+it("should not resolve module requests relative", async () => {
+	await expect(import("./module.mjs")).rejects.toMatchObject({
+		code: "MODULE_NOT_FOUND"
+	});
+});

test/cases/errors/module-request/module.mjs

@@ -0,0 +1 @@
+import "dependency.js";