From 7ad29702c03cd9f135b46a2aad43553637bb2971 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miguel=20Beteg=C3=B3n?= <miguelbetegongarcia@gmail.com>
Date: Thu, 9 Apr 2026 15:42:18 +0200
Subject: [PATCH] feat(init): pre-read common config files to reduce
 round-trips

After computing the directory listing, pre-read ~35 common config files
(manifests, framework configs, Sentry configs) if they exist. Send the
results as fileCache in the startAsync input data.

Workflow steps already check fileCache before suspending for read-files,
so this eliminates 1-3 HTTP round-trips with no server-side changes
needed (the fileCache field is already in step schemas).

Capped at 512KB total to avoid sending excessive data upfront.

Made-with: Cursor
---
 src/lib/init/local-ops.ts     | 77 +++++++++++++++++++++++++++++++++++
 src/lib/init/wizard-runner.ts | 11 ++++-
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/src/lib/init/local-ops.ts b/src/lib/init/local-ops.ts
index 4908bac3e..89ce9c298 100644
--- a/src/lib/init/local-ops.ts
+++ b/src/lib/init/local-ops.ts
@@ -284,6 +284,83 @@ export async function precomputeDirListing(
   return (result.data as { entries?: DirEntry[] })?.entries ?? [];
 }
 
+/**
+ * Common config file names that are frequently requested by multiple workflow
+ * steps (discover-context, detect-platform, plan-codemods). Pre-reading them
+ * eliminates 1-3 suspend/resume round-trips.
+ */
+const COMMON_CONFIG_FILES = [
+  "package.json",
+  "tsconfig.json",
+  "pyproject.toml",
+  "Gemfile",
+  "go.mod",
+  "build.gradle",
+  "build.gradle.kts",
+  "pom.xml",
+  "Cargo.toml",
+  "pubspec.yaml",
+  "mix.exs",
+  "composer.json",
+  "next.config.js",
+  "next.config.mjs",
+  "next.config.ts",
+  "nuxt.config.ts",
+  "nuxt.config.js",
+  "angular.json",
+  "astro.config.mjs",
+  "astro.config.ts",
+  "svelte.config.js",
+  "remix.config.js",
+  "vite.config.ts",
+  "vite.config.js",
+  "webpack.config.js",
+  "sentry.client.config.ts",
+  "sentry.client.config.js",
+  "sentry.server.config.ts",
+  "sentry.server.config.js",
+  "sentry.edge.config.ts",
+  "sentry.edge.config.js",
+  "instrumentation.ts",
+  "instrumentation.js",
+];
+
+const MAX_PREREAD_TOTAL_BYTES = 512 * 1024;
+
+/**
+ * Pre-read common config files that exist in the directory listing.
+ * Returns a fileCache map (path -> content or null) that the server
+ * can use to skip read-files suspend/resume round-trips.
+ */
+export async function preReadCommonFiles(
+  directory: string,
+  dirListing: DirEntry[]
+): Promise<Record<string, string | null>> {
+  const listingPaths = new Set(dirListing.map((e) => e.path));
+  const toRead = COMMON_CONFIG_FILES.filter((f) => listingPaths.has(f));
+
+  const cache: Record<string, string | null> = {};
+  let totalBytes = 0;
+
+  for (const filePath of toRead) {
+    if (totalBytes >= MAX_PREREAD_TOTAL_BYTES) {
+      break;
+    }
+    try {
+      const absPath = path.join(directory, filePath);
+      const content = await fs.promises.readFile(absPath, "utf-8");
+      if (totalBytes + content.length <= MAX_PREREAD_TOTAL_BYTES) {
+        cache[filePath] = content;
+        totalBytes += content.length;
+      }
+    } catch {
+      cache[filePath] = null;
+    }
+  }
+
+  return cache;
+}
+
 export async function handleLocalOp(
   payload: LocalOpPayload,
   options: WizardOptions
diff --git a/src/lib/init/wizard-runner.ts b/src/lib/init/wizard-runner.ts
index ed08a977b..b8a9b3731 100644
--- a/src/lib/init/wizard-runner.ts
+++ b/src/lib/init/wizard-runner.ts
@@ -47,6 +47,7 @@ import {
   detectExistingProject,
   handleLocalOp,
   precomputeDirListing,
+  preReadCommonFiles,
   resolveOrgSlug,
   tryGetExistingProject,
 } from "./local-ops.js";
@@ -616,12 +617,20 @@ export async function runWizard(initialOptions: WizardOptions): Promise<void> {
   let result: WorkflowRunResult;
   try {
     const dirListing = await precomputeDirListing(directory);
+    const fileCache = await preReadCommonFiles(directory, dirListing);
     spin.message("Connecting to wizard...");
     run = await workflow.createRun();
     result = assertWorkflowResult(
       await withTimeout(
         run.startAsync({
-          inputData: { directory, yes, dryRun, features, dirListing },
+          inputData: {
+            directory,
+            yes,
+            dryRun,
+            features,
+            dirListing,
+            fileCache,
+          },
           tracingOptions,
         }),
         API_TIMEOUT_MS,