From 0caffd38159cc0535d45a636d922a77385bcecb0 Mon Sep 17 00:00:00 2001
From: Mike Lewis <mtlewis@users.noreply.github.com>
Date: Wed, 11 Apr 2018 22:14:51 +0100
Subject: [PATCH] Generalise package main resolving issue

Resolves #5967
---
 .../__mocks__/mock-module-alt/index.js                    | 8 ++++++++
 .../__mocks__/mock-module-alt/package.json                | 4 ++++
 .../__tests__/resolve-node-module.test.js                 | 7 ++++++-
 packages/jest-resolve/src/default_resolver.js             | 6 +++++-
 4 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 integration-tests/resolve-node-module/__mocks__/mock-module-alt/index.js
 create mode 100644 integration-tests/resolve-node-module/__mocks__/mock-module-alt/package.json

diff --git a/integration-tests/resolve-node-module/__mocks__/mock-module-alt/index.js b/integration-tests/resolve-node-module/__mocks__/mock-module-alt/index.js
new file mode 100644
index 000000000000..acc83d1123dc
--- /dev/null
+++ b/integration-tests/resolve-node-module/__mocks__/mock-module-alt/index.js
@@ -0,0 +1,8 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+module.exports = 'test';
diff --git a/integration-tests/resolve-node-module/__mocks__/mock-module-alt/package.json b/integration-tests/resolve-node-module/__mocks__/mock-module-alt/package.json
new file mode 100644
index 000000000000..0297f3861468
--- /dev/null
+++ b/integration-tests/resolve-node-module/__mocks__/mock-module-alt/package.json
@@ -0,0 +1,4 @@
+{
+  "name": "mock-module",
+  "main": "./"
+}
diff --git a/integration-tests/resolve-node-module/__tests__/resolve-node-module.test.js b/integration-tests/resolve-node-module/__tests__/resolve-node-module.test.js
index b008272f042a..fb900b6a8550 100644
--- a/integration-tests/resolve-node-module/__tests__/resolve-node-module.test.js
+++ b/integration-tests/resolve-node-module/__tests__/resolve-node-module.test.js
@@ -15,7 +15,12 @@ it('should resolve entry as index.js when package main is "."', () => {
   expect(mockModule).toEqual('test');
 });
 
-it('should resolve entry as index with other configured module file extention when package main is "."', () => {
+it('should resolve entry as index.js when package main is "./"', () => {
+  const mockModule = require('mock-module-alt');
+  expect(mockModule).toEqual('test');
+});
+
+it('should resolve entry as index with other configured module file extension when package main is "."', () => {
   const mockJsxModule = require('mock-jsx-module');
   expect(mockJsxModule).toEqual('test jsx');
 });
diff --git a/packages/jest-resolve/src/default_resolver.js b/packages/jest-resolve/src/default_resolver.js
index beffc1a19ef5..72f5706d4aa8 100644
--- a/packages/jest-resolve/src/default_resolver.js
+++ b/packages/jest-resolve/src/default_resolver.js
@@ -129,7 +129,7 @@ function resolveSync(target: Path, options: ResolverOptions): Path {
       pkgmain = JSON.parse(body).main;
     } catch (e) {}
 
-    if (pkgmain && pkgmain !== '.') {
+    if (pkgmain && !isCurrentDirectory(pkgmain)) {
       const resolveTarget = path.resolve(name, pkgmain);
       const result = tryResolve(resolveTarget);
       if (result) {
@@ -175,3 +175,7 @@ function isDirectory(dir: Path): boolean {
 
   return result;
 }
+
+function isCurrentDirectory(testPath: Path): boolean {
+  return path.resolve('.') === path.resolve(testPath);
+}