From 1e2363c07b37ec671a570f0ac7e8522a61ee8c36 Mon Sep 17 00:00:00 2001
From: Eemeli Aro <eemeli@gmail.com>
Date: Sat, 24 Jul 2021 19:13:57 +0300
Subject: [PATCH] fix(node-resolve): handle browser-mapped paths correctly in
 nested contexts (#920)

---
 packages/node-resolve/src/index.js            |  2 +-
 packages/node-resolve/test/browser.js         | 35 ++++++++++++++++++-
 .../test/fixtures/browser-local-relative.js   |  4 +++
 .../fixtures/nested/browser-local-relative.js |  4 +++
 .../node-resolve/test/fixtures/package.json   |  1 +
 5 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100755 packages/node-resolve/test/fixtures/browser-local-relative.js
 create mode 100755 packages/node-resolve/test/fixtures/nested/browser-local-relative.js

diff --git a/packages/node-resolve/src/index.js b/packages/node-resolve/src/index.js
index 5bd18c1e9..a8ba3da29 100644
--- a/packages/node-resolve/src/index.js
+++ b/packages/node-resolve/src/index.js
@@ -88,7 +88,7 @@ export function nodeResolve(opts = {}) {
         return { id: ES6_BROWSER_EMPTY };
       }
       const browserImportee =
-        browser[importee] ||
+        (importee[0] !== '.' && browser[importee]) ||
         browser[resolvedImportee] ||
         browser[`${resolvedImportee}.js`] ||
         browser[`${resolvedImportee}.json`];
diff --git a/packages/node-resolve/test/browser.js b/packages/node-resolve/test/browser.js
index 67897ce99..b62f17249 100644
--- a/packages/node-resolve/test/browser.js
+++ b/packages/node-resolve/test/browser.js
@@ -146,7 +146,7 @@ test('allows use of object browser field, resolving nested directories', async (
   t.is(module.exports.test, 43);
 });
 
-test('respects local browser field', async (t) => {
+test('respects local browser field for external dependencies', async (t) => {
   const bundle = await rollup({
     input: 'browser-local.js',
     onwarn: () => t.fail('No warnings were expected'),
@@ -161,6 +161,39 @@ test('respects local browser field', async (t) => {
   t.is(module.exports, 'component-type');
 });
 
+test('respects local browser field for internal dependencies', async (t) => {
+  const bundle = await rollup({
+    input: 'browser-local-relative.js',
+    onwarn: () => t.fail('No warnings were expected'),
+    plugins: [
+      nodeResolve({
+        mainFields: ['browser', 'main']
+      })
+    ]
+  });
+  const { module } = await testBundle(t, bundle);
+
+  t.is(module.exports, 'component-type');
+});
+
+test('does not apply local browser field for matching imports in nested paths', async (t) => {
+  try {
+    await rollup({
+      input: 'nested/browser-local-relative.js',
+      onwarn: () => t.fail('No warnings were expected'),
+      plugins: [
+        nodeResolve({
+          mainFields: ['browser', 'main']
+        })
+      ]
+    });
+  } catch (e) {
+    t.is(e.code, 'UNRESOLVED_IMPORT');
+    return;
+  }
+  t.fail('expecting error');
+});
+
 test('allows use of object browser field, resolving to nested node_modules', async (t) => {
   const bundle = await rollup({
     input: 'browser-entry-points-to-node-module.js',
diff --git a/packages/node-resolve/test/fixtures/browser-local-relative.js b/packages/node-resolve/test/fixtures/browser-local-relative.js
new file mode 100755
index 000000000..6a83ab6a5
--- /dev/null
+++ b/packages/node-resolve/test/fixtures/browser-local-relative.js
@@ -0,0 +1,4 @@
+// test browser mapped imports from the main entrypoint
+import s from './dummy-relative';
+
+export default s;
diff --git a/packages/node-resolve/test/fixtures/nested/browser-local-relative.js b/packages/node-resolve/test/fixtures/nested/browser-local-relative.js
new file mode 100755
index 000000000..6a83ab6a5
--- /dev/null
+++ b/packages/node-resolve/test/fixtures/nested/browser-local-relative.js
@@ -0,0 +1,4 @@
+// test browser mapped imports from the main entrypoint
+import s from './dummy-relative';
+
+export default s;
diff --git a/packages/node-resolve/test/fixtures/package.json b/packages/node-resolve/test/fixtures/package.json
index a58c25b80..28bd9c9b7 100755
--- a/packages/node-resolve/test/fixtures/package.json
+++ b/packages/node-resolve/test/fixtures/package.json
@@ -8,6 +8,7 @@
   "scripts": {},
   "keywords": [],
   "browser": {
+    "./dummy-relative": "component-type",
     "dummy-module": "component-type"
   }
 }