From e4e03bd9092d421e2ce71b09a00db517a850f532 Mon Sep 17 00:00:00 2001
From: Iwo Plaza <plazaiwo@meta.com>
Date: Tue, 18 Feb 2025 07:37:57 -0800
Subject: [PATCH] Trace the import path that leads to an untranslatable file
 (#49480)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49480

Changelog: [Internal]

Reviewed By: huntie

Differential Revision: D69752685

fbshipit-source-id: 94f70eeaec35c864c15b463f3afce929765f2c40
---
 scripts/build/build-types/buildTypes.js       | 27 +++++++---
 .../build-types/resolution/getRequireStack.js | 51 +++++++++++++++++++
 2 files changed, 70 insertions(+), 8 deletions(-)
 create mode 100644 scripts/build/build-types/resolution/getRequireStack.js

diff --git a/scripts/build/build-types/buildTypes.js b/scripts/build/build-types/buildTypes.js
index 53e6ff99a4b..de463c4b426 100644
--- a/scripts/build/build-types/buildTypes.js
+++ b/scripts/build/build-types/buildTypes.js
@@ -10,6 +10,7 @@
  */
 
 const {PACKAGES_DIR, REPO_ROOT} = require('../../consts');
+const getRequireStack = require('./resolution/getRequireStack');
 const translatedModuleTemplate = require('./templates/translatedModule.d.ts-template');
 const translateSourceFile = require('./translateSourceFile');
 const debug = require('debug')('build-types:main');
@@ -64,14 +65,16 @@ async function buildTypes(): Promise<void> {
     ENTRY_POINTS.map(file => path.join(REPO_ROOT, file)),
   );
   const translatedFiles = new Set<string>();
+  const dependencyEdges: DependencyEdges = [];
 
   while (files.size > 0) {
-    const dependencies = await translateSourceFiles(files);
+    const dependencies = await translateSourceFiles(dependencyEdges, files);
+    dependencyEdges.push(...dependencies);
 
     files.forEach(file => translatedFiles.add(file));
     files.clear();
 
-    for (const dep of dependencies) {
+    for (const [, dep] of dependencies) {
       if (
         !translatedFiles.has(dep) &&
         !IGNORE_PATTERNS.some(pattern => micromatch.isMatch(dep, pattern))
@@ -80,13 +83,14 @@ async function buildTypes(): Promise<void> {
       }
     }
   }
-
-  await translateSourceFiles(files);
 }
 
+type DependencyEdges = Array<[string, string]>;
+
 async function translateSourceFiles(
-  inputFiles: $ReadOnlySet<string>,
-): Promise<Set<string>> {
+  dependencyEdges: DependencyEdges,
+  inputFiles: Iterable<string>,
+): Promise<DependencyEdges> {
   const files = new Set<string>([...inputFiles]);
 
   // Require common interface file (js.flow) or base implementation (.js) for
@@ -128,7 +132,7 @@ async function translateSourceFiles(
     }
   }
 
-  const dependencies = new Set<string>();
+  const dependencies: DependencyEdges = [];
 
   await Promise.all(
     Array.from(files).map(async file => {
@@ -140,7 +144,7 @@ async function translateSourceFiles(
           await translateSourceFile(source, file);
 
         for (const dep of fileDeps) {
-          dependencies.add(dep);
+          dependencies.push([file, dep]);
         }
 
         await fs.mkdir(path.dirname(buildPath), {recursive: true});
@@ -153,6 +157,13 @@ async function translateSourceFiles(
         );
       } catch (e) {
         console.error(`Failed to build ${path.relative(REPO_ROOT, file)}\n`, e);
+        const requireStack = getRequireStack(dependencyEdges, file);
+        if (requireStack.length > 0) {
+          console.error('Chain of imports that led to this file:');
+          for (const stackEntry of requireStack) {
+            console.error(`- ${stackEntry}`);
+          }
+        }
       }
     }),
   );
diff --git a/scripts/build/build-types/resolution/getRequireStack.js b/scripts/build/build-types/resolution/getRequireStack.js
new file mode 100644
index 00000000000..c45a912355f
--- /dev/null
+++ b/scripts/build/build-types/resolution/getRequireStack.js
@@ -0,0 +1,51 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ * @oncall react_native
+ */
+
+type DependencyEdges = Array<[string, string]>;
+
+/**
+ * Given a containing dependency graph and an input file, get the first
+ * complete path found when traversing dependant module edges up to the root
+ * entry file. Any require cycles will be pruned.
+ *
+ * Time complexity: O(edges^2)
+ * Space complexity: O(edges)
+ */
+function getRequireStack(edges: DependencyEdges, file: string): Array<string> {
+  const requireStack = new Set<string>();
+  const cycleRoots = new Set<string>();
+  let currentTarget = file;
+
+  while (true) {
+    const edge = edges.find(
+      ([, targetFile]) =>
+        targetFile === currentTarget && !cycleRoots.has(targetFile),
+    );
+
+    if (edge == null) {
+      break;
+    }
+
+    const [sourceFile] = edge;
+
+    if (requireStack.has(sourceFile)) {
+      requireStack.clear();
+      cycleRoots.add(sourceFile);
+    }
+
+    requireStack.add(sourceFile);
+    currentTarget = sourceFile;
+  }
+
+  return Array.from(requireStack);
+}
+
+module.exports = getRequireStack;