fix(nitro): normalize module paths for windows virtual modules

.changeset/fix-windows-nitro-module-paths.md

@@ -0,0 +1,7 @@
+---
+'evlog': patch
+---
+
+Fix `evlog/nitro` and `evlog/nitro/v3` on Windows. The module passed native `path.resolve()` paths to `nitro.options.plugins` and `nitro.options.errorHandler`. Nitro raw-interpolates those into the `#nitro/virtual/plugins` and `#nitro/virtual/error-handler` JS string literals, so Windows backslashes were parsed as escape sequences (`\n`, `\v`, …) and broke module resolution — surfacing as `Cannot find module … imported from '#nitro/virtual/error-handler'`. Paths are now normalized to forward slashes before being handed to Nitro.
+
+Closes [#345](https://github.com/HugoRCD/evlog/issues/345).

packages/evlog/src/nitro-v3/module.ts

@@ -7,29 +7,37 @@ export type { NitroModuleOptions }
 
 const _dir = dirname(fileURLToPath(import.meta.url))
 
+// Nitro raw-interpolates these paths into JS string literals when generating
+// the #nitro/virtual/plugins and #nitro/virtual/error-handler modules, so
+// Windows backslashes would be parsed as escape sequences (\n, \v, …) and
+// break module resolution. Normalize to POSIX separators.
+function resolveModulePath(name: string): string {
+  return resolve(_dir, name).replace(/\\/g, '/')
+}
+
 export default function evlog(options?: NitroModuleOptions) {
   return {
     name: 'evlog',
     setup(nitro: Nitro) {
       // Push the plugin (no extension — Nitro's bundler resolves it)
       nitro.options.plugins = nitro.options.plugins || []
-      nitro.options.plugins.push(resolve(_dir, 'plugin'))
+      nitro.options.plugins.push(resolveModulePath('plugin'))
 
       // explicitly tell nitro to bundle evlog's files to correctly resolve nitro dependencies
       if (!nitro.options.noExternals) {
         nitro.options.noExternals = ['evlog']
       } else if (Array.isArray(nitro.options.noExternals)) {
         nitro.options.noExternals.push('evlog')
       }
-      
+
 
       // Set error handler only if not already configured by user
       if (!nitro.options.errorHandler) {
-        nitro.options.errorHandler = [resolve(_dir, 'errorHandler')]
+        nitro.options.errorHandler = [resolveModulePath('errorHandler')]
       } else if (Array.isArray(nitro.options.errorHandler)) {
-        nitro.options.errorHandler.unshift(resolve(_dir, 'errorHandler'))
+        nitro.options.errorHandler.unshift(resolveModulePath('errorHandler'))
       } else if (typeof nitro.options.errorHandler === 'string') {
-        nitro.options.errorHandler = [resolve(_dir, 'errorHandler'), nitro.options.errorHandler]
+        nitro.options.errorHandler = [resolveModulePath('errorHandler'), nitro.options.errorHandler]
       }
 
       // Inject config into runtimeConfig — works in production where the

packages/evlog/src/nitro/module.ts

@@ -7,17 +7,25 @@ export type { NitroModuleOptions }
 
 const _dir = dirname(fileURLToPath(import.meta.url))
 
+// Nitro raw-interpolates these paths into JS string literals when generating
+// the #nitro/virtual/plugins and #nitro/virtual/error-handler modules, so
+// Windows backslashes would be parsed as escape sequences (\n, \v, …) and
+// break module resolution. Normalize to POSIX separators.
+function resolveModulePath(name: string): string {
+  return resolve(_dir, name).replace(/\\/g, '/')
+}
+
 export default function evlog(options?: NitroModuleOptions) {
   return {
     name: 'evlog',
     setup(nitro: Nitro) {
       // Push the plugin (no extension — Nitro's bundler resolves it)
       nitro.options.plugins = nitro.options.plugins || []
-      nitro.options.plugins.push(resolve(_dir, 'plugin'))
+      nitro.options.plugins.push(resolveModulePath('plugin'))
 
       // Set error handler only if not already configured by user
       if (!nitro.options.errorHandler) {
-        nitro.options.errorHandler = resolve(_dir, 'errorHandler')
+        nitro.options.errorHandler = resolveModulePath('errorHandler')
       }
 
       // explicitly tell nitro to bundle evlog's files to correctly resolve nitro dependencies

packages/evlog/test/nitro/module-paths.test.ts

@@ -0,0 +1,51 @@
+import { describe, expect, it } from 'vitest'
+import nitroV2Module from '../../src/nitro/module'
+import nitroV3Module from '../../src/nitro-v3/module'
+
+// Nitro builds its #nitro/virtual/plugins and #nitro/virtual/error-handler
+// virtual modules by raw-interpolating these paths into JS string literals:
+//   import _abc from "${plugin}"
+//   import errorHandler$0 from "${h}"
+// On Windows, path.resolve() returns paths with backslashes (e.g. C:\…\plugin).
+// Those backslashes would then be parsed as JS escape sequences (\n, \v, …),
+// silently corrupting the specifier. Regression test for evlog#345.
+describe('nitro modules avoid backslash paths', () => {
+  function makeNitroStub() {
+    return {
+      options: {
+        plugins: [] as string[],
+        errorHandler: undefined as string | string[] | undefined,
+        noExternals: undefined as undefined | true | string[],
+        runtimeConfig: {} as Record<string, unknown>,
+      },
+    }
+  }
+
+  it('nitro v2 module pushes POSIX-style plugin and errorHandler paths', () => {
+    const nitro = makeNitroStub()
+    nitroV2Module({ env: { service: 'test' } }).setup(nitro as never)
+
+    expect(nitro.options.plugins).toHaveLength(1)
+    expect(nitro.options.plugins[0]).not.toMatch(/\\/)
+    expect(nitro.options.plugins[0]).toMatch(/\/nitro\/plugin$/)
+
+    expect(nitro.options.errorHandler).toBeTypeOf('string')
+    expect(nitro.options.errorHandler).not.toMatch(/\\/)
+    expect(nitro.options.errorHandler).toMatch(/\/nitro\/errorHandler$/)
+  })
+
+  it('nitro v3 module pushes POSIX-style plugin and errorHandler paths', () => {
+    const nitro = makeNitroStub()
+    nitroV3Module({ env: { service: 'test' } }).setup(nitro as never)
+
+    expect(nitro.options.plugins).toHaveLength(1)
+    expect(nitro.options.plugins[0]).not.toMatch(/\\/)
+    expect(nitro.options.plugins[0]).toMatch(/\/nitro-v3\/plugin$/)
+
+    expect(Array.isArray(nitro.options.errorHandler)).toBe(true)
+    const handlers = nitro.options.errorHandler as string[]
+    expect(handlers).toHaveLength(1)
+    expect(handlers[0]).not.toMatch(/\\/)
+    expect(handlers[0]).toMatch(/\/nitro-v3\/errorHandler$/)
+  })
+})