fix: Apply expanded env to process.env (#2267)

Author: aklinker1

.gitignore

@@ -1,6 +1,7 @@
 .DS_Store
 .env
 .env.*
+!packages/wxt/src/core/utils/__tests__/fixtures/.env
 .idea
 .output
 .webextrc

.tool-versions

@@ -1 +1,2 @@
 bun 1.3.12
+nodejs 24.14.1

bun.lock

@@ -0,0 +1,42 @@
+import { beforeEach, describe, expect, it } from 'vitest';
+import { loadEnv } from '../env';
+
+const cwd = process.cwd();
+
+describe('Env Utils', () => {
+  beforeEach(() => {
+    if (process.cwd() !== cwd) process.chdir(cwd);
+    delete process.env.TEST_VAR;
+    delete process.env.EXPANDED;
+  });
+
+  describe('loadEnv', () => {
+    beforeEach(() => {
+      process.chdir(`${import.meta.dirname}/fixtures`);
+    });
+
+    it('should load env vars into the real `process.env`', () => {
+      loadEnv('testing', 'chrome');
+      expect(process.env.TEST_VAR).toEqual('expected');
+    });
+
+    it('should override blank strings in process.env', () => {
+      process.env.TEST_VAR = '';
+      loadEnv('testing', 'chrome');
+      expect(process.env.TEST_VAR).toEqual('expected');
+    });
+
+    it('should not override non-blank strings in process.env', () => {
+      process.env.TEST_VAR = 'non-blank';
+      loadEnv('testing', 'chrome');
+      expect(process.env.TEST_VAR).toEqual('non-blank');
+    });
+
+    // Node doesn't return vars in the same order as they're defined:
+    // https://github.com/nodejs/node/issues/62736
+    it.skip('should expand env vars into the real `process.env`', () => {
+      loadEnv('testing', 'chrome');
+      expect(process.env.EXPANDED).toEqual('expected expanded');
+    });
+  });
+});

packages/wxt/src/core/utils/__tests__/env.test.ts

@@ -0,0 +1,2 @@
+TEST_VAR="expected"
+EXPANDED="$TEST_VAR expanded"

packages/wxt/src/core/utils/__tests__/fixtures/.env

@@ -1,6 +1,6 @@
-import { readFileSync, existsSync } from 'node:fs';
-import { parseEnv } from 'node:util';
 import { expand } from 'dotenv-expand';
+import { existsSync, readFileSync } from 'node:fs';
+import { parseEnv } from 'node:util';
 import type { TargetBrowser } from '../../types';
 
 /** Load environment files based on the current mode and browser. */
@@ -32,13 +32,8 @@ export function loadEnv(mode: string, browser: TargetBrowser) {
     }),
   );
 
-  // Make a copy of `process.env` so that `dotenv-expand` doesn't re-assign the
-  // expanded values to the global `process.env`.
-  const processEnv = { ...process.env } as Record<string, string>;
-
   expand({
     parsed,
-    processEnv,
   });
 
   return parsed;