Revert "Use ESM entrypoint for require(ESM)" (#17156)

Co-authored-by: Tatsunori Uchino <tats.u@live.jp>

changelog_unreleased/misc/17156.md

@@ -0,0 +1,3 @@
+#### Remove `module-sync` condition (#17156 by @fisker)
+
+In Prettier 3.5.0, [we added `module-sync` condition to `package.json`](https://prettier.io/blog/2025/02/09/3.5.0#use-esm-entrypoint-for-requireesm-16958-by-tats-u), so that `require("prettier")` can use ESM version, but turns out it doesn't work if CommonJS and ESM plugins both imports builtin plugins. To solve this problem, we decide simply remove the `module-sync` condition, so `require("prettier")` will still use the CommonJS version, we'll revisit until `require(ESM)` feature is more stable.

package.json

@@ -15,7 +15,6 @@
   "exports": {
     ".": {
       "types": "./src/index.d.ts",
-      "module-sync": "./src/index.js",
       "require": "./src/index.cjs",
       "default": "./src/index.js"
     },

scripts/build/build-package-json.js

@@ -42,7 +42,6 @@ async function buildPackageJson({ file, files }) {
     exports: {
       ".": {
         types: "./index.d.ts",
-        "module-sync": "./index.mjs",
         require: "./index.cjs",
         browser: {
           import: "./standalone.mjs",
@@ -56,14 +55,14 @@ async function buildPackageJson({ file, files }) {
           .filter((file) => file.output.format === "umd")
           .map((file) => {
             const basename = path.basename(file.output.file, ".js");
-            const mjsPath = `./${file.output.file.replace(/\.js$/u, ".mjs")}`;
             return [
               file.isPlugin ? `./plugins/${basename}` : `./${basename}`,
               {
                 types: `./${file.output.file.replace(/\.js$/u, ".d.ts")}`,
-                "module-sync": mjsPath,
+                // `module-sync` condition can prevent CJS plugins from working: https://github.com/prettier/prettier/issues/17139
+                // Perform a test before re-adding it.
                 require: `./${file.output.file}`,
-                default: mjsPath,
+                default: `./${file.output.file.replace(/\.js$/u, ".mjs")}`,
               },
             ];
           }),

website/blog/2025-02-09-3.5.0.md

@@ -398,6 +398,12 @@ If you can't upgrade Prettier for some reason, you can still use JSONC syntax in
 
 #### Use ESM entrypoint for `require(ESM)` ([#16958](https://github.com/prettier/prettier/pull/16958) by [@tats-u](https://github.com/tats-u))
 
+:::info
+
+This change has been reverted in v3.5.2, check [#17139](https://github.com/prettier/prettier/pull/17139) for details.
+
+:::
+
 Node.js 22.12 or later [can (experimentally) load ESM modules with `require` function](https://nodejs.org/api/modules.html#loading-ecmascript-modules-using-require) without runtime flags. This change enables `require` to load Prettier without the CommonJS entrypoint with almost only the ability to import the ESM entrypoint.
 
 The feature to load ES modules with `require` is not completely stable but can be used without ExperimentalWarning as of Node 22.13.