From cf6e12274d055502c3e983b27bfb05b839850c2a Mon Sep 17 00:00:00 2001
From: Durvesh Pilankar <durveshpilankar@meta.com>
Date: Mon, 29 Jun 2026 21:51:55 -0700
Subject: [PATCH] Fix RAM bundle passing the deps function (not its result) to
 getTransformOptions

getRamBundleInfo gives custom getTransformOptions a callback to look up a
module's transitive dependencies, but it called `Array.from(getDependencies)`
on the function itself instead of `Array.from(getDependencies(x))`. Since
the closure has arity 1, Array.from treated it as array-like and returned
[undefined], so any getTransformOptions relying on this callback received
garbage regardless of the file queried.

Invoke getDependencies(x). Existing tests never exercised the callback,
which masked this.

Adds a regression test that calls the callback and asserts the real
transitive deps (fails before / passes after).
---
 .../__tests__/getRamBundleInfo-test.js        | 41 +++++++++++++++++++
 .../Serializers/getRamBundleInfo.js           |  2 +-
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/packages/metro/src/DeltaBundler/Serializers/__tests__/getRamBundleInfo-test.js b/packages/metro/src/DeltaBundler/Serializers/__tests__/getRamBundleInfo-test.js
index c988afebe4..6fc33a61d2 100644
--- a/packages/metro/src/DeltaBundler/Serializers/__tests__/getRamBundleInfo-test.js
+++ b/packages/metro/src/DeltaBundler/Serializers/__tests__/getRamBundleInfo-test.js
@@ -112,6 +112,47 @@ test('should return the RAM bundle info', async () => {
   ).toMatchSnapshot();
 });
 
+test('passes a working transitive-dependency lookup to getTransformOptions', async () => {
+  let resolvedDeps;
+  await getRamBundleInfo(
+    '/root/entry.js',
+    pre,
+    {...graph, entryPoints: new Set(['/root/entry.js'])},
+    {
+      asyncRequireModulePath: '',
+      // $FlowFixMe[incompatible-type] createModuleId assumes numeric IDs - is this too strict?
+      createModuleId: path => path,
+      dev: true,
+      excludeSource: false,
+      getRunModuleStatement,
+      getTransformOptions: async (entryPoints, opts, getDependenciesOf) => {
+        resolvedDeps = await getDependenciesOf('/root/foo.js');
+        return {preloadedModules: {}, ramGroups: []};
+      },
+      globalPrefix: '',
+      includeAsyncPaths: false,
+      inlineSourceMap: false,
+      modulesOnly: false,
+      platform: null,
+      processModuleFilter: module => true,
+      projectRoot: '/root',
+      runBeforeMainModule: [],
+      runModule: true,
+      serverRoot: '/root',
+      shouldAddToIgnoreList: () => false,
+      sourceMapUrl: 'http://localhost/bundle.map',
+      sourceUrl: null,
+      getSourceUrl: null,
+    },
+  );
+  // foo depends on bar, baz, qux — the callback must return those, not [undefined].
+  expect([...resolvedDeps].sort()).toEqual([
+    '/root/bar.js',
+    '/root/baz.js',
+    '/root/qux.js',
+  ]);
+});
+
 test('emits x_google_ignoreList based on shouldAddToIgnoreList', async () => {
   expect(
     await getRamBundleInfo(
diff --git a/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js b/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js
index 9b8047ec08..997f6561cc 100644
--- a/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js
+++ b/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js
@@ -160,7 +160,7 @@ async function _getRamOptions(
     /* $FlowFixMe[incompatible-type](>=0.99.0 site=react_native_fb) This comment suppresses an
      * error found when Flow v0.99 was deployed. To see the error, delete this
      * comment and run Flow. */
-    async (x: string) => Array.from(getDependencies),
+    async (x: string) => Array.from(getDependencies(x)),
   );
 
   return {