From 1a5c5e9924be7ed4039e5b4200fcff3505106631 Mon Sep 17 00:00:00 2001
From: kwy404 <thekaway404@gmail.com>
Date: Fri, 23 Oct 2026 18:03:31 -0300
Subject: [PATCH] Fix empty file list in ambiguous module resolution errors

---
 packages/metro/src/lib/TerminalReporter.js    |  2 +-
 .../lib/__tests__/formatBundlingError-test.js | 25 +++++++++++++++++++
 packages/metro/src/lib/formatBundlingError.js |  5 +---
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/packages/metro/src/lib/TerminalReporter.js b/packages/metro/src/lib/TerminalReporter.js
index b9e9d6a048..cb5b86e324 100644
--- a/packages/metro/src/lib/TerminalReporter.js
+++ b/packages/metro/src/lib/TerminalReporter.js
@@ -331,7 +331,7 @@ export default class TerminalReporter {
         `${error.fromModulePath}\` tries to require \`${he.hasteName}\`, ` +
         'but there are several files providing this module. You can delete ' +
         'or fix them: \n\n' +
-        Object.keys(he.duplicatesSet)
+        [...he.duplicatesSet.keys()]
           .sort()
           .map(dupFilePath => `  * \`${dupFilePath}\`\n`)
           .join('');
diff --git a/packages/metro/src/lib/__tests__/formatBundlingError-test.js b/packages/metro/src/lib/__tests__/formatBundlingError-test.js
index 6cfc985b31..ea34b38c08 100644
--- a/packages/metro/src/lib/__tests__/formatBundlingError-test.js
+++ b/packages/metro/src/lib/__tests__/formatBundlingError-test.js
@@ -10,8 +10,33 @@
 
 import {UnableToResolveError} from '../../node-haste/DependencyGraph/ModuleResolution';
 import formatBundlingError from '../formatBundlingError';
+import {AmbiguousModuleResolutionError} from 'metro-core';
+import FileMap, {DuplicateHasteCandidatesError} from 'metro-file-map';
 
 describe('formatBundlingError', () => {
+  test('AmbiguousModuleResolutionError', () => {
+    const hasteError = new DuplicateHasteCandidatesError(
+      'target',
+      FileMap.H.GENERIC_PLATFORM,
+      false,
+      new Map([
+        ['/root/a.js', FileMap.H.MODULE],
+        ['/root/b.js', FileMap.H.MODULE],
+      ]),
+    );
+    expect(
+      formatBundlingError(
+        new AmbiguousModuleResolutionError('/origin/module.js', hasteError),
+      ),
+    ).toMatchObject({
+      type: 'AmbiguousModuleResolutionError',
+      message:
+        "Ambiguous resolution: module '/origin/module.js' tries to require " +
+        "'target', but there are several files providing this module. You " +
+        'can delete or fix them: \n\n/root/a.js\n\n/root/b.js',
+    });
+  });
+
   test('UnableToResolveError', () => {
     expect(
       formatBundlingError(
diff --git a/packages/metro/src/lib/formatBundlingError.js b/packages/metro/src/lib/formatBundlingError.js
index c84262dcfd..02294e6570 100644
--- a/packages/metro/src/lib/formatBundlingError.js
+++ b/packages/metro/src/lib/formatBundlingError.js
@@ -43,10 +43,7 @@ export default function formatBundlingError(
       `${error.fromModulePath}\' tries to require \'${he.hasteName}\', but ` +
       'there are several files providing this module. You can delete or ' +
       'fix them: \n\n' +
-      Object.keys(he.duplicatesSet)
-        .sort()
-        .map(dupFilePath => `${dupFilePath}`)
-        .join('\n\n');
+      [...he.duplicatesSet.keys()].sort().join('\n\n');
 
     return {
       type: 'AmbiguousModuleResolutionError',