From 981315521d908447c3784129487bd95ce07650e1 Mon Sep 17 00:00:00 2001
From: Riccardo Cipolleschi <cipolleschi@meta.com>
Date: Tue, 15 Oct 2024 08:13:14 -0700
Subject: [PATCH] Codegen fails with Local Module (#47027)

Summary:

While I was writing the documentation for extracting a module in a library, I realized that Codegen ignored the local node modules.

The reason is that `require.resolve` fails to resolve a local path.

## Changelog
[General][Fixed] - Make Codegen work with local modules

Reviewed By: cortinico

Differential Revision: D64242713
---
 .../codegen/generate-artifacts-executor.js    | 28 +++++++++++++------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/packages/react-native/scripts/codegen/generate-artifacts-executor.js b/packages/react-native/scripts/codegen/generate-artifacts-executor.js
index bfb5463d2149..8e89bf0007ff 100644
--- a/packages/react-native/scripts/codegen/generate-artifacts-executor.js
+++ b/packages/react-native/scripts/codegen/generate-artifacts-executor.js
@@ -254,17 +254,29 @@ function findExternalLibraries(pkgJson, projectRoot) {
   );
   // Handle third-party libraries
   return Object.keys(dependencies).flatMap(dependency => {
+    let configFilePath = '';
     try {
-      const configFilePath = require.resolve(
-        path.join(dependency, 'package.json'),
-        {paths: [projectRoot]},
-      );
-      const configFile = JSON.parse(fs.readFileSync(configFilePath));
-      const codegenConfigFileDir = path.dirname(configFilePath);
-      return extractLibrariesFromJSON(configFile, codegenConfigFileDir);
+      configFilePath = require.resolve(path.join(dependency, 'package.json'), {
+        paths: [projectRoot],
+      });
     } catch (e) {
-      return [];
+      // require.resolve fails if the dependency is a local node module.
+      if (
+        dependencies[dependency].startsWith('.') || // handles relative paths
+        dependencies[dependency].startsWith('/') // handles absolute paths
+      ) {
+        configFilePath = path.join(
+          projectRoot,
+          pkgJson.dependencies[dependency],
+          'package.json',
+        );
+      } else {
+        return [];
+      }
     }
+    const configFile = JSON.parse(fs.readFileSync(configFilePath));
+    const codegenConfigFileDir = path.dirname(configFilePath);
+    return extractLibrariesFromJSON(configFile, codegenConfigFileDir);
   });
 }