fix: note the conditions under which the request couldn't be found (#460)

Author: KTibow

lib/ExportsFieldPlugin.js

@@ -114,9 +114,14 @@ module.exports = class ExportsFieldPlugin {
 				}
 
 				if (paths.length === 0) {
+					const conditions = [...this.conditionNames];
+					const conditionsStr =
+						conditions.length === 1
+							? `the condition "${conditions[0]}"`
+							: `the conditions ${JSON.stringify(conditions)}`;
 					return callback(
 						new Error(
-							`Package path ${remainingRequest} is not exported from package ${request.descriptionFileRoot} (see exports field in ${request.descriptionFilePath})`,
+							`"${remainingRequest}" is not exported under ${conditionsStr} from package ${request.descriptionFileRoot} (see exports field in ${request.descriptionFilePath})`,
 						),
 					);
 				}

test/exportsField.test.js

@@ -2352,7 +2352,7 @@ describe("exportsFieldPlugin", () => {
 		resolver.resolve({}, fixture2, "exports-field?foo", {}, (err, result) => {
 			if (!err) return done(new Error(`expect error, got ${result}`));
 			expect(err).toBeInstanceOf(Error);
-			expect(err.message).toMatch(/Package path \.\/\?foo is not exported/);
+			expect(err.message).toMatch(/"\.\/\?foo" is not exported/);
 			done();
 		});
 	});
@@ -2381,7 +2381,7 @@ describe("exportsFieldPlugin", () => {
 		resolver.resolve({}, fixture2, "exports-field#foo", {}, (err, result) => {
 			if (!err) return done(new Error(`expect error, got ${result}`));
 			expect(err).toBeInstanceOf(Error);
-			expect(err.message).toMatch(/Package path \.\/#foo is not exported/);
+			expect(err.message).toMatch(/"\.\/#foo" is not exported/);
 			done();
 		});
 	});
@@ -2470,7 +2470,9 @@ describe("exportsFieldPlugin", () => {
 			(err, result) => {
 				if (!err) return done(new Error(`expect error, got ${result}`));
 				expect(err).toBeInstanceOf(Error);
-				expect(err.message).toMatch(/not exported from package/);
+				expect(err.message).toMatch(
+					/not exported under the condition "webpack" from package/,
+				);
 				done();
 			},
 		);
@@ -2837,7 +2839,7 @@ describe("exportsFieldPlugin", () => {
 				if (!err) return done(new Error(`expect error, got ${result}`));
 				expect(err).toBeInstanceOf(Error);
 				expect(err.message).toMatch(
-					/Package path \.\/features\/internal\/file\.js is not exported/,
+					/"\.\/features\/internal\/file\.js" is not exported/,
 				);
 				done();
 			},
@@ -2937,9 +2939,7 @@ describe("exportsFieldPlugin", () => {
 		resolver.resolve({}, fixture, "pkg/string.js", {}, (err, result) => {
 			if (!err) return done(new Error(`expect error, got ${result}`));
 			expect(err).toBeInstanceOf(Error);
-			expect(err.message).toMatch(
-				/Package path \.\/string\.ts is not exported/,
-			);
+			expect(err.message).toMatch(/"\.\/string\.ts" is not exported/);
 			done();
 		});
 	});
@@ -2962,9 +2962,7 @@ describe("exportsFieldPlugin", () => {
 		resolver.resolve({}, fixture, "pkg/string.js", {}, (err, result) => {
 			if (!err) return done(new Error(`expect error, got ${result}`));
 			expect(err).toBeInstanceOf(Error);
-			expect(err.message).toMatch(
-				/Package path \.\/string\.ts is not exported/,
-			);
+			expect(err.message).toMatch(/"\.\/string\.ts" is not exported/);
 			done();
 		});
 	});