refactor: patch loadManifest using ast-grep (#393)

Author: vicb

packages/cloudflare/src/cli/build/bundle-server.ts

@@ -14,6 +14,7 @@ import { inlineEvalManifest } from "./patches/plugins/eval-manifest.js";
 import { patchFetchCacheSetMissingWaitUntil } from "./patches/plugins/fetch-cache-wait-until.js";
 import { inlineFindDir } from "./patches/plugins/find-dir.js";
 import { patchLoadInstrumentation } from "./patches/plugins/load-instrumentation.js";
+import { inlineLoadManifest } from "./patches/plugins/load-manifest.js";
 import { handleOptionalDependencies } from "./patches/plugins/optional-deps.js";
 import { fixRequire } from "./patches/plugins/require.js";
 import { shimRequireHook } from "./patches/plugins/require-hook.js";
@@ -93,6 +94,7 @@ export async function bundleServer(buildOpts: BuildOptions): Promise<void> {
       patchFetchCacheSetMissingWaitUntil(updater),
       inlineEvalManifest(updater, buildOpts),
       inlineFindDir(updater, buildOpts),
+      inlineLoadManifest(updater, buildOpts),
       // Apply updater updaters, must be the last plugin
       updater.plugin,
     ],
@@ -196,7 +198,6 @@ export async function updateWorkerBundledCode(
   const patchedCode = await patchCodeWithValidations(code, [
     ["require", patches.patchRequire],
     ["`buildId` function", (code) => patches.patchBuildId(code, buildOpts)],
-    ["`loadManifest` function", (code) => patches.patchLoadManifest(code, buildOpts)],
     ["cacheHandler", (code) => patches.patchCache(code, buildOpts)],
     [
       "'require(this.middlewareManifestPath)'",

packages/cloudflare/src/cli/build/patches/plugins/eval-manifest.ts

@@ -61,7 +61,7 @@ function evalManifest($PATH, $$$ARGS) {
     fix: `
 function evalManifest($PATH, $$$ARGS) {
   ${returnManifests}
-  throw new Error("Unknown evalManifest: " + $PATH);
+  throw new Error(\`Unexpected evalManifest(\${$PATH}) call!\`);
 }`,
   } satisfies RuleConfig;
 }

packages/cloudflare/src/cli/build/patches/plugins/load-manifest.ts

@@ -0,0 +1,60 @@
+/**
+ * Inline `loadManifest` as it relies on `readFileSync`that is not supported by workerd.
+ */
+
+import { readFile } from "node:fs/promises";
+import { join, relative } from "node:path";
+
+import { type BuildOptions, getPackagePath } from "@opennextjs/aws/build/helper.js";
+import { getCrossPlatformPathRegex } from "@opennextjs/aws/utils/regex.js";
+import { glob } from "glob";
+
+import { normalizePath } from "../../utils/normalize-path.js";
+import { patchCode, type RuleConfig } from "../ast/util.js";
+import type { ContentUpdater } from "./content-updater.js";
+
+export function inlineLoadManifest(updater: ContentUpdater, buildOpts: BuildOptions) {
+  return updater.updateContent(
+    "inline-load-manifest",
+    {
+      filter: getCrossPlatformPathRegex(String.raw`/next/dist/server/load-manifest\.js$`, { escape: false }),
+      contentFilter: /function loadManifest\(/,
+    },
+    async ({ contents }) => patchCode(contents, await getRule(buildOpts))
+  );
+}
+
+async function getRule(buildOpts: BuildOptions) {
+  const { outputDir } = buildOpts;
+
+  const baseDir = join(outputDir, "server-functions/default", getPackagePath(buildOpts));
+  const dotNextDir = join(baseDir, ".next");
+
+  const manifests = await glob(join(dotNextDir, "**/*-manifest.json"));
+
+  const returnManifests = (
+    await Promise.all(
+      manifests.map(
+        async (manifest) => `
+            if ($PATH.endsWith("${normalizePath("/" + relative(dotNextDir, manifest))}")) {
+              return ${await readFile(manifest, "utf-8")};
+            }
+          `
+      )
+    )
+  ).join("\n");
+
+  return {
+    rule: {
+      pattern: `
+function loadManifest($PATH, $$$ARGS) {
+  $$$_
+}`,
+    },
+    fix: `
+function loadManifest($PATH, $$$ARGS) {
+  ${returnManifests}
+  throw new Error(\`Unexpected loadManifest(\${$PATH}) call!\`);
+}`,
+  } satisfies RuleConfig;
+}

packages/cloudflare/src/cli/build/patches/to-investigate/patch-read-file.ts

@@ -1,10 +1,4 @@
-import { readFileSync } from "node:fs";
-import { join, relative } from "node:path";
-
-import { type BuildOptions, getBuildId, getPackagePath } from "@opennextjs/aws/build/helper.js";
-import { globSync } from "glob";
-
-import { normalizePath } from "../../utils/index.js";
+import { type BuildOptions, getBuildId } from "@opennextjs/aws/build/helper.js";
 
 export function patchBuildId(code: string, buildOpts: BuildOptions): string {
   // The Next code gets the buildId from the filesystem so we hardcode the value at build time.
@@ -15,30 +9,3 @@ export function patchBuildId(code: string, buildOpts: BuildOptions): string {
     `
   );
 }
-
-export function patchLoadManifest(code: string, buildOpts: BuildOptions): string {
-  // Inline manifest that Next would otherwise retrieve from the file system.
-
-  const { outputDir } = buildOpts;
-
-  const baseDir = join(outputDir, "server-functions/default", getPackagePath(buildOpts));
-  const dotNextDir = join(baseDir, ".next");
-
-  const manifests = globSync(join(dotNextDir, "**/*-manifest.json"));
-
-  return code.replace(
-    /function loadManifest\((.+?), .+?\) {/,
-    `$&
-    ${manifests
-      .map(
-        (manifest) => `
-          if ($1.endsWith("${normalizePath("/" + relative(dotNextDir, manifest))}")) {
-            return ${readFileSync(manifest, "utf-8")};
-          }
-        `
-      )
-      .join("\n")}
-    throw new Error("Unknown loadManifest: " + $1);
-    `
-  );
-}