fix: align proxy routing across fetch and downloader

tests/unit/utils/proxy-env.test.ts

@@ -0,0 +1,96 @@
+import { afterEach, beforeEach, describe, expect, it } from 'bun:test';
+import { getProxyResolution, shouldBypassProxy } from '../../../src/utils/proxy-env';
+
+const PROXY_ENV_KEYS = [
+  'http_proxy',
+  'HTTP_PROXY',
+  'https_proxy',
+  'HTTPS_PROXY',
+  'all_proxy',
+  'ALL_PROXY',
+  'no_proxy',
+  'NO_PROXY',
+] as const;
+
+describe('proxy env helpers', () => {
+  const originalEnv = new Map<string, string | undefined>();
+
+  beforeEach(() => {
+    for (const key of PROXY_ENV_KEYS) {
+      originalEnv.set(key, process.env[key]);
+      delete process.env[key];
+    }
+  });
+
+  afterEach(() => {
+    for (const key of PROXY_ENV_KEYS) {
+      const value = originalEnv.get(key);
+      if (value === undefined) {
+        delete process.env[key];
+      } else {
+        process.env[key] = value;
+      }
+    }
+  });
+
+  describe('getProxyResolution', () => {
+    it('falls back from invalid HTTPS_PROXY to valid HTTP_PROXY for HTTPS requests', () => {
+      process.env.HTTPS_PROXY = 'not-a-valid-url';
+      process.env.HTTP_PROXY = 'http://http-proxy:8080';
+
+      expect(getProxyResolution(true, process.env, { allowedProtocols: ['http:', 'https:'] })).toEqual(
+        {
+          url: 'http://http-proxy:8080',
+        }
+      );
+    });
+
+    it('preserves socks proxy URLs when no protocol restriction is requested', () => {
+      process.env.https_proxy = 'socks5://proxy:1080';
+
+      expect(getProxyResolution(true)).toEqual({ url: 'socks5://proxy:1080' });
+    });
+
+    it('falls back from unsupported HTTPS_PROXY to valid ALL_PROXY when protocols are restricted', () => {
+      process.env.https_proxy = 'socks5://proxy:1080';
+      process.env.ALL_PROXY = 'http://all-proxy:8080';
+
+      expect(getProxyResolution(true, process.env, { allowedProtocols: ['http:', 'https:'] })).toEqual(
+        {
+          url: 'http://all-proxy:8080',
+        }
+      );
+    });
+
+    it('returns an error when only invalid proxy env values are configured for restricted protocols', () => {
+      process.env.https_proxy = 'socks5://proxy:1080';
+      process.env.HTTP_PROXY = 'not-a-valid-url';
+
+      expect(getProxyResolution(true, process.env, { allowedProtocols: ['http:', 'https:'] })).toEqual(
+        {
+          error: 'Unsupported proxy protocol: socks5:',
+        }
+      );
+    });
+  });
+
+  describe('shouldBypassProxy', () => {
+    it('automatically bypasses loopback hosts without NO_PROXY', () => {
+      expect(shouldBypassProxy('localhost')).toBe(true);
+      expect(shouldBypassProxy('api.localhost')).toBe(true);
+      expect(shouldBypassProxy('0.0.0.0')).toBe(true);
+      expect(shouldBypassProxy('127.0.0.2')).toBe(true);
+      expect(shouldBypassProxy('::1')).toBe(true);
+      expect(shouldBypassProxy('::ffff:127.0.0.1')).toBe(true);
+      expect(shouldBypassProxy('::ffff:7f00:1')).toBe(true);
+    });
+
+    it('supports wildcard NO_PROXY domain suffix patterns', () => {
+      process.env.NO_PROXY = '*.example.com';
+
+      expect(shouldBypassProxy('example.com')).toBe(true);
+      expect(shouldBypassProxy('api.example.com')).toBe(true);
+      expect(shouldBypassProxy('other.test')).toBe(false);
+    });
+  });
+});