Refactor filesystem operations to

  async for concurrent I/O (concurrent optimisations not yet done)

  Replace synchronous filesystem
  operations with async/await throughout
   the codebase
  to enable concurrent file reads and
  improve bundler performance. The
  Context interface
  now uses AsyncFilesystem exclusively,
  allowing multiple file operations to
  run in
  parallel using Promise.all() where
  beneficial.

  Key changes:
  - Replace Filesystem with
  AsyncFilesystem in Context interface
  - Add AsyncNodeFs and AsyncRecordingFs
   implementations using fs/promises
  - Update all filesystem operations to
  use async/await
  - Parallelize file existence checks
  and reads where possible
  - Maintain backward compatibility with
   synchronous RecordingFs for tests

  This sets the foundation for improved
  build performance through concurrent
  I/O
  operations, particularly beneficial
  when reading many files during
  bundling.

Author: front-depiction

bun.lock

@@ -1,6 +1,6 @@
 import * as Sentry from "@sentry/node";
 import { Ora } from "ora";
-import { Filesystem, nodeFs } from "./fs.js";
+import { AsyncFilesystem, asyncNodeFs } from "./fs.js";
 import { initializeBigBrainAuth } from "../cli/lib/deploymentSelection.js";
 import { logFailure, logVerbose } from "./log.js";
 // How the error should be handled when running `npx convex dev`.
@@ -54,7 +54,7 @@ export type BigBrainAuth = {
 );
 
 export interface Context {
-  fs: Filesystem;
+  fs: AsyncFilesystem;
   deprecationMessagePrinted: boolean;
   // Reports to Sentry and either throws FatalError or exits the process.
   // Prints the `printedMessage` if provided
@@ -97,7 +97,7 @@ class OneoffContextImpl {
     string,
     (exitCode: number, err?: any) => Promise<void>
   > = {};
-  public fs: Filesystem = nodeFs;
+  public fs: AsyncFilesystem = asyncNodeFs;
   public deprecationMessagePrinted: boolean = false;
   public spinner: Ora | undefined = undefined;
   private _bigBrainAuth: BigBrainAuth | null = null;

src/bundler/context.ts

@@ -25,7 +25,7 @@ async function resolveNodeModule(
     }))
   ) {
     const maybePath = path.join(nodeModulesPath, moduleDir);
-    if (ctx.fs.exists(maybePath)) {
+    if (await ctx.fs.exists(maybePath)) {
       return maybePath;
     }
     resolveDir = path.dirname(path.dirname(nodeModulesPath));
@@ -116,7 +116,7 @@ export async function computeExternalPackages(
   const externalPackages = new Map<string, ExternalPackage>();
   let packageJson: any;
   try {
-    const packageJsonString = ctx.fs.readUtf8File(packageJsonPath);
+    const packageJsonString = await ctx.fs.readUtf8File(packageJsonPath);
     packageJson = JSON.parse(packageJsonString);
   } catch (error: any) {
     return await ctx.crash({
@@ -165,7 +165,7 @@ export async function computeExternalPackages(
         "node_modules",
         getModule(packageName).dirName,
       );
-      if (ctx.fs.exists(packagePath)) {
+      if (await ctx.fs.exists(packagePath)) {
         externalPackages.set(packageName, {
           path: packagePath,
         });
@@ -223,7 +223,7 @@ export async function findExactVersionAndDependencies(
   const modulePackageJsonPath = path.join(modulePath, "package.json");
   let modulePackageJson: any;
   try {
-    const packageJsonString = ctx.fs.readUtf8File(modulePackageJsonPath);
+    const packageJsonString = await ctx.fs.readUtf8File(modulePackageJsonPath);
     modulePackageJson = JSON.parse(packageJsonString);
   } catch {
     return await ctx.crash({