fix: normalize loader import path to compiled file

package.json

@@ -43,6 +43,7 @@
     "npm-run-all": "4.1.5",
     "rimraf": "3.0.2",
     "semantic-release": "17.4.2",
+    "slash": "3.0.0",
     "ts-jest": "26.5.4",
     "ts-node": "9.1.1",
     "typescript": "4.2.3",

src/index.ts

@@ -9,6 +9,7 @@ import type { WebpackPluginInstance } from 'webpack';
 import type { Source } from 'webpack-sources';
 import WebpackVirtualModules from 'webpack-virtual-modules';
 
+import { createLoaderCode } from './loader';
 import type { Compiler, EntryPoint, WebpackOptionsNormalized } from './normalized';
 import type { Options, Prepared, PreprocessedEntry, PreprocessedOutput, ProcessedOptions } from './types';
 
@@ -287,13 +288,6 @@ class BytenodeWebpackPlugin implements WebpackPluginInstance {
   }
 }
 
-function createLoaderCode(relativePath: string): string {
-  return `
-    require('bytenode');
-    require('${relativePath}');
-  `;
-}
-
 function prepare(context: string | undefined, location: string | string[], name?: string, suffix = ''): Prepared {
   const locationArray = Array.isArray(location) ? location : [location];
 

src/loader.ts

@@ -0,0 +1,31 @@
+import { platform } from 'os';
+import { win32 } from 'path';
+
+import slash from 'slash';
+
+function createLoaderCode(relativePath: string): string {
+  if (/win32/.test(platform()) && win32.isAbsolute(relativePath)) {
+    relativePath = exhaustiveReplace(relativePath, /\/\//g, '/');
+    relativePath = exhaustiveReplace(relativePath, /\//g, '\\');
+    relativePath = exhaustiveReplace(relativePath, /\\\\/g, '\\');
+    relativePath = relativePath.replace(/\\/g, '\\\\');
+  } else {
+    relativePath = slash(relativePath);
+  }
+
+  return `
+    require('bytenode');
+    require('${relativePath}');
+  `;
+}
+
+function exhaustiveReplace(source: string, regex: RegExp, target: string): string {
+  if (regex.test(source)) {
+    return exhaustiveReplace(source.replace(regex, target), regex, target);
+  }
+  return source;
+}
+
+export {
+  createLoaderCode,
+};

test/loader.test.ts

@@ -0,0 +1,84 @@
+describe('createLoaderCode', () => {
+
+  for (const platform of ['darwin', 'linux'] as NodeJS.Platform[]) {
+    describe(`${platform}`, () => {
+
+      describe('absolute', () => {
+        test('backwards', async () => {
+          await mockPlatform(platform);
+          await testLoaderCode('\\a\\b\\c', '/a/b/c');
+        });
+
+        test('forwards', async () => {
+          await mockPlatform(platform);
+          await testLoaderCode('/a/b/c', '/a/b/c');
+        });
+      });
+
+      describe('relative', () => {
+        test('backwards', async () => {
+          await mockPlatform(platform);
+          await testLoaderCode('.\\a\\b\\c', './a/b/c');
+        });
+
+        test('forwards', async () => {
+          await mockPlatform(platform);
+          await testLoaderCode('./a/b/c', './a/b/c');
+        });
+      });
+
+    });
+  }
+
+  describe('win32', () => {
+
+    describe('absolute', () => {
+      test('backwards', async () => {
+        await mockPlatform('win32');
+        await testLoaderCode('A:\\b\\c', 'A:\\\\b\\\\c');
+      });
+
+      test('forwards', async () => {
+        await mockPlatform('win32');
+        await testLoaderCode('A:/b/c', 'A:\\\\b\\\\c');
+      });
+    });
+
+    describe('relative', () => {
+      test('backwards', async () => {
+        await mockPlatform('win32');
+        await testLoaderCode('.\\a\\b\\c', './a/b/c');
+      });
+
+      test('forwards', async () => {
+        await mockPlatform('win32');
+        await testLoaderCode('./a/b/c', './a/b/c');
+      });
+    });
+
+  });
+
+});
+
+async function mockPlatform(platform: NodeJS.Platform): Promise<void> {
+  jest.resetModules();
+  jest.doMock('os', () => {
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+    const os = jest.requireActual('os');
+
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+    return { ...os, platform: () => platform };
+  });
+
+  const os = await import('os');
+  expect(os.platform()).toBe(platform);
+}
+
+async function testLoaderCode(from: string, to: string): Promise<void> {
+  const { createLoaderCode } = await import('../src/loader');
+
+  expect(createLoaderCode(from)).toBe(`
+    require('bytenode');
+    require('${to}');
+  `);
+}