WIP: switch specifier resolution warning to custom message

IRL, both internal and external instances of ESMLoader happen. in the test, only 1 external happens and then the test fails.

Author: JakobJingleheimer

lib/internal/modules/esm/loader.js

@@ -108,15 +108,21 @@ class ESMLoader {
    */
   translators = translators;
 
-  constructor() {
+  constructor(isInternal = false) {
+console.log({ isInternal })
+    if (isInternal) return;
+
     if (getOptionValue('--experimental-loader')) {
       emitExperimentalWarning('Custom ESM Loaders');
     }
     if (getOptionValue('--experimental-network-imports')) {
       emitExperimentalWarning('Network Imports');
     }
     if (getOptionValue('--experimental-specifier-resolution') === 'node') {
-      emitExperimentalWarning('Specifier Resolution');
+      process.emitWarning(
+        'The Node.js specifier resolution flag is experimental. It could change or be removed at any time.',
+        'ExperimentalWarning'
+      );
     }
   }
 

lib/internal/process/esm_loader.js

@@ -39,7 +39,7 @@ async function importModuleDynamicallyCallback(wrap, specifier, assertions) {
   throw new ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING();
 };
 
-const esmLoader = new ESMLoader();
+const esmLoader = new ESMLoader(true);
 
 exports.esmLoader = esmLoader;
 

test/es-module/test-esm-experimental-warnings.mjs

@@ -9,23 +9,30 @@ for (
   const [experiment, arg] of [
     [/Custom ESM Loaders/, `--experimental-loader=${fileURL('es-module-loaders', 'hooks-custom.mjs')}`],
     [/Network Imports/, '--experimental-network-imports'],
-    [/Specifier Resolution/, '--experimental-specifier-resolution=node'],
+    [/specifier resolution/, '--experimental-specifier-resolution=node'],
   ]
 ) {
+  const input = `import ${JSON.stringify(fileURL('es-module-loaders','module-named-exports.mjs'))}`;
+console.log({ input })
   const child = spawn(execPath, [
     arg,
     '--input-type=module',
     '--eval',
-    'const foo = "a"',
+    input,
   ]);
 
   let stderr = '';
   child.stderr.setEncoding('utf8');
   child.stderr.on('data', (data) => { stderr += data; });
+
+  let stdout = '';
+  child.stdout.setEncoding('utf8');
+  child.stdout.on('data', (data) => { stdout += data; });
   child.on('close', mustCall((code, signal) => {
+console.log({ experiment, code, signal, stderr, stdout })
     strictEqual(code, 0);
     strictEqual(signal, null);
-    match(stderr, /ExperimentalWarning:/);
+    match(stderr, /ExperimentalWarning/);
     match(stderr, experiment);
   }));
 }