fix: cross-platform prebuild downloads

src/cache.ts

@@ -22,6 +22,7 @@ type HashTree = { [path: string]: string | HashTree };
 type CacheOptions = {
   ABI: string;
   arch: string;
+  platform: string;
   debug: boolean;
   electronVersion: string;
   headerURL: string;
@@ -159,6 +160,7 @@ export async function generateCacheKey(opts: CacheOptions): Promise<string> {
     .update(path.basename(opts.modulePath))
     .update(opts.ABI)
     .update(opts.arch)
+    .update(opts.platform)
     .update(opts.debug ? 'debug' : 'not debug')
     .update(opts.headerURL)
     .update(opts.electronVersion);

src/module-type/node-gyp/node-gyp.ts

@@ -84,6 +84,10 @@ export class NodeGyp extends NativeModule {
   }
 
   async rebuildModule(): Promise<void> {
+    if (this.rebuilder.platform !== process.platform) {
+      throw new Error("node-gyp does not support cross-compiling native modules from source.");
+    }
+
     if (this.modulePath.includes(' ')) {
       console.error('Attempting to build a module with a space in the path');
       console.error('See https://github.com/nodejs/node-gyp/issues/65#issuecomment-368820565 for reasons why this may not work');

src/rebuild.ts

@@ -19,6 +19,13 @@ export interface RebuildOptions {
    * The version of Electron to build against.
    */
   electronVersion: string;
+  /**
+   * Override the target platform to something other than the host system platform.
+   * Note: This only applies to downloading prebuilt binaries. **It is not possible to cross-compile native modules.**
+   * 
+   * @defaultValue The system {@link https://nodejs.org/api/process.html#processplatform | `process.platform`} value
+   */
+  platform?: NodeJS.Platform;
   /**
    * Override the target rebuild architecture to something other than the host system architecture.
    * 
@@ -132,7 +139,7 @@ export class Rebuilder implements IRebuilder {
   public lifecycle: EventEmitter;
   public buildPath: string;
   public electronVersion: string;
-  public platform: string = process.platform;
+  public platform: NodeJS.Platform;
   public arch: string;
   public force: boolean;
   public headerURL: string;
@@ -151,6 +158,7 @@ export class Rebuilder implements IRebuilder {
     this.lifecycle = options.lifecycle;
     this.buildPath = options.buildPath;
     this.electronVersion = options.electronVersion;
+    this.platform = options.platform || process.platform;
     this.arch = options.arch || process.arch;
     this.force = options.force || false;
     this.headerURL = options.headerURL || 'https://www.electronjs.org/headers';
@@ -199,6 +207,7 @@ export class Rebuilder implements IRebuilder {
       'rebuilding with args:',
       this.buildPath,
       this.electronVersion,
+      this.platform,
       this.arch,
       extraModules,
       this.force,
@@ -289,6 +298,7 @@ export class Rebuilder implements IRebuilder {
       cacheKey = await generateCacheKey({
         ABI: this.ABI,
         arch: this.arch,
+        platform: this.platform,
         debug: this.debug,
         electronVersion: this.electronVersion,
         headerURL: this.headerURL,

src/types.ts

@@ -21,7 +21,7 @@ export interface IRebuilder {
   lifecycle: EventEmitter;
   mode: RebuildMode;
   msvsVersion?: string;
-  platform: string;
+  platform: NodeJS.Platform;
   prebuildTagPrefix: string;
   buildFromSource: boolean;
   useCache: boolean;

test/module-type-node-gyp.ts

@@ -1,10 +1,13 @@
 import { EventEmitter } from 'events';
-import { expect } from 'chai';
+import chai, { expect } from 'chai';
+import chaiAsPromised from 'chai-as-promised';
 
 import { cleanupTestModule, resetTestModule, TEST_MODULE_PATH as testModulePath } from './helpers/module-setup';
 import { NodeGyp } from '../lib/module-type/node-gyp/node-gyp';
 import { Rebuilder } from '../lib/rebuild';
 
+chai.use(chaiAsPromised);
+
 describe('node-gyp', () => {
   describe('buildArgs', () => {
 
@@ -54,5 +57,27 @@ describe('node-gyp', () => {
         expect(args).to.not.include('--force-process-config');
       });
     });
+
+    context('cross-compilation', async () => {
+      it('throws error early if platform mismatch', async function () {
+        let platform: NodeJS.Platform = 'darwin';
+
+        // we're verifying platform mismatch error throwing, not `rebuildModule` rebuilding.
+        if (process.platform === platform) {
+          platform = 'win32';
+        }
+
+        const rebuilder = new Rebuilder({
+          buildPath: testModulePath,
+          electronVersion: '15.3.0',
+          lifecycle: new EventEmitter(),
+          platform
+        });
+        const nodeGyp = new NodeGyp(rebuilder, testModulePath);
+
+        const errorMessage = "node-gyp does not support cross-compiling native modules from source.";
+        expect(nodeGyp.rebuildModule()).to.eventually.be.rejectedWith(new Error(errorMessage))
+      })
+    })
   });
 });

test/module-type-node-pre-gyp.ts

@@ -5,15 +5,15 @@ import path from 'path';
 
 import { cleanupTestModule, resetTestModule, TIMEOUT_IN_MILLISECONDS, TEST_MODULE_PATH as testModulePath } from './helpers/module-setup';
 import { NodePreGyp } from '../lib/module-type/node-pre-gyp';
-import { Rebuilder } from '../lib/rebuild';
+import { Rebuilder, RebuilderOptions } from '../lib/rebuild';
 
 chai.use(chaiAsPromised);
 
 describe('node-pre-gyp', function () {
   this.timeout(TIMEOUT_IN_MILLISECONDS);
 
   const modulePath = path.join(testModulePath, 'node_modules', 'sqlite3');
-  const rebuilderArgs = {
+  const rebuilderArgs: RebuilderOptions = {
     buildPath: testModulePath,
     electronVersion: '8.0.0',
     arch: process.arch,
@@ -64,4 +64,21 @@ describe('node-pre-gyp', function () {
     nodePreGyp = new NodePreGyp(rebuilder, modulePath);
     expect(await nodePreGyp.findPrebuiltModule()).to.equal(true);
   });
+
+  it('should download for target platform', async () => {
+    let rebuilder = new Rebuilder(rebuilderArgs);
+    let nodePreGyp = new NodePreGyp(rebuilder, modulePath);
+    expect(await nodePreGyp.findPrebuiltModule()).to.equal(true);
+
+    let alternativePlatform: NodeJS.Platform;
+    if (process.platform === 'win32') {
+      alternativePlatform = 'darwin';
+    } else {
+      alternativePlatform = 'win32';
+    }
+
+    rebuilder = new Rebuilder({ ...rebuilderArgs, platform: alternativePlatform });
+    nodePreGyp = new NodePreGyp(rebuilder, modulePath);
+    expect(await nodePreGyp.findPrebuiltModule()).to.equal(true);
+  });
 });

test/module-type-prebuild-install.ts

@@ -5,13 +5,13 @@ import path from 'path';
 
 import { cleanupTestModule, resetTestModule, TIMEOUT_IN_MILLISECONDS, TEST_MODULE_PATH as testModulePath } from './helpers/module-setup';
 import { PrebuildInstall } from '../lib/module-type/prebuild-install';
-import { Rebuilder } from '../lib/rebuild';
+import { Rebuilder, RebuilderOptions } from '../lib/rebuild';
 
 chai.use(chaiAsPromised);
 
 describe('prebuild-install', () => {
   const modulePath = path.join(testModulePath, 'node_modules', 'farmhash');
-  const rebuilderArgs = {
+  const rebuilderArgs: RebuilderOptions = {
     buildPath: testModulePath,
     electronVersion: '8.0.0',
     arch: process.arch,
@@ -52,5 +52,25 @@ describe('prebuild-install', () => {
       const prebuildInstall = new PrebuildInstall(rebuilder, modulePath);
       expect(prebuildInstall.findPrebuiltModule()).to.eventually.be.rejectedWith("Native module 'farmhash' requires Node-API but Electron v2.0.0 does not support Node-API");
     });
+
+    it('should download for target platform', async function () {
+      if (process.platform === 'darwin' && process.arch === 'arm64') {
+        this.skip(); // farmhash module has no prebuilt binaries for ARM64
+      }
+      let rebuilder = new Rebuilder(rebuilderArgs);
+      let prebuild = new PrebuildInstall(rebuilder, modulePath);
+      expect(await prebuild.findPrebuiltModule()).to.equal(true);
+
+      let alternativePlatform: NodeJS.Platform;
+      if (process.platform === 'win32') {
+        alternativePlatform = 'darwin';
+      } else {
+        alternativePlatform = 'win32';
+      }
+
+      rebuilder = new Rebuilder({ ...rebuilderArgs, platform: alternativePlatform });
+      prebuild = new PrebuildInstall(rebuilder, modulePath);
+      expect(await prebuild.findPrebuiltModule()).to.equal(true);
+    });
   });
 });

test/module-type-prebuildify.ts

@@ -113,4 +113,24 @@ describe('prebuildify', () => {
       });
     });
   });
+
+  describe('cross-platform downloads', async () => {
+    it('should download for target platform', async () => {
+      const fixtureDir = path.join(fixtureBaseDir, 'napi');
+      let rebuilder = createRebuilder();
+      let prebuildify = new Prebuildify(rebuilder, fixtureDir);
+      expect(await prebuildify.findPrebuiltModule()).to.equal(true);
+
+      let alternativePlatform: NodeJS.Platform;
+      if (process.platform === 'win32') {
+        alternativePlatform = 'darwin';
+      } else {
+        alternativePlatform = 'win32';
+      }
+
+      rebuilder = createRebuilder({ platform: alternativePlatform });
+      prebuildify = new Prebuildify(rebuilder, fixtureDir);
+      expect(await prebuildify.findPrebuiltModule()).to.equal(true);
+    });
+  })
 });