fix: make empty-import-meta warning more actionable (#1561)

src/runtimes/node/bundlers/esbuild/bundler.ts

@@ -207,6 +207,17 @@ var __glob = (map) => (path) => {
     const cleanTempFiles = getCleanupFunction([...bundlePaths.keys()])
     const additionalPaths = includedFilesFromModuleDetection
 
+    const updatedWarnings = warnings.map((warning) => {
+      if (warning.id === 'empty-import-meta') {
+        return {
+          ...warning,
+          text: `"import.meta" is not available and will be empty, use __dirname instead`,
+        }
+      }
+
+      return warning
+    })
+
     return {
       additionalPaths,
       bundlePaths,
@@ -215,7 +226,7 @@ var __glob = (map) => (path) => {
       moduleFormat,
       nativeNodeModules,
       outputExtension,
-      warnings,
+      warnings: updatedWarnings,
     }
   } catch (error) {
     throw FunctionBundlingUserError.addCustomErrorInfo(error, {

tests/fixtures/import-meta-warning/function.ts

@@ -0,0 +1,10 @@
+export const handler = async () => ({
+  statusCode: 200,
+  body: JSON.stringify({
+    msg: "Hello from .ts",
+    v: 2,
+    // @ts-ignore Error expected
+    importMetaURL: import.meta.url,
+    dirname: typeof __dirname === "undefined" ? undefined : __dirname,
+  }),
+});

tests/main.test.ts

@@ -2765,4 +2765,17 @@ describe('zip-it-and-ship-it', () => {
       expect(handler()).toBe(true)
     }
   })
+
+  testMany('esbuild hides unactionable import.meta warning', ['bundler_esbuild'], async (options) => {
+    const {
+      files: [{ bundlerWarnings }],
+    } = await zipFixture('import-meta-warning', {
+      length: 1,
+      opts: options,
+    })
+    expect(bundlerWarnings).toHaveLength(1)
+    expect((bundlerWarnings?.[0] as any).text).toEqual(
+      `"import.meta" is not available and will be empty, use __dirname instead`,
+    )
+  })
 })