From a61c32b6a342ec543ec1817b79255fdb8917a372 Mon Sep 17 00:00:00 2001
From: Nicola Corti <ncor@meta.com>
Date: Fri, 11 Sep 2026 05:35:23 -0700
Subject: [PATCH 1/5] Match Prettier coverage with `arc f`

Summary:
Use the public Prettier configuration for the complete OSS JavaScript and documentation surface. Expose `yarn format-javascript` and `yarn format-check-javascript`, and compose them into the repository-wide commands.

Changelog: [Internal]

Differential Revision: D119487610
---
 package.json | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/package.json b/package.json
index cdba8ff29db9..b5dc3eafc1ef 100644
--- a/package.json
+++ b/package.json
@@ -15,8 +15,10 @@
     "cxx-api-validate": "python -m scripts.cxx-api.parser --validate",
     "flow-check": "flow full-check",
     "flow": "flow",
-    "format-check": "prettier --list-different \"./**/*.{js,md,yml,ts,tsx}\"",
-    "format": "npm run prettier && npm run clang-format",
+    "format-check": "yarn format-check-javascript",
+    "format-check-javascript": "prettier --check \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
+    "format": "yarn format-javascript && yarn clang-format",
+    "format-javascript": "prettier --write \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
     "featureflags": "yarn --cwd packages/react-native featureflags",
     "js-api-diff": "node ./scripts/js-api/diff-api-snapshot",
     "lint-kotlin-check": "./gradlew ktfmtCheck",
@@ -24,7 +26,6 @@
     "lint-markdown": "markdownlint-cli2 2>&1",
     "lint": "eslint --max-warnings 0 .",
     "preinstall": "node ./scripts/try-set-hermes-compiler-prebuilt.js",
-    "prettier": "prettier --write \"./**/*.{js,md,yml,ts,tsx}\"",
     "shellcheck": "./.github/workflow-scripts/analyze_scripts.sh",
     "start": "yarn --cwd packages/rn-tester start",
     "set-version": "node ./scripts/releases/set-version.js",

From 636b709191ae53df900714e27acfb133a981e17c Mon Sep 17 00:00:00 2001
From: Nicola Corti <ncor@meta.com>
Date: Fri, 11 Sep 2026 05:35:23 -0700
Subject: [PATCH 2/5] Check all C-family sources with clang-format

Summary:
Add npm-driven clang-format commands for exported C-family sources. Expose `yarn format-cpp` and `yarn format-check-cpp`, and compose them into the repository-wide commands. The wrapper automatically selects the repository-provided formatter for its environment.

Changelog: [Internal]

Differential Revision: D119487611
---
 .clang-format-ignore    |  3 ++
 package.json            |  7 +++--
 scripts/clang-format.js | 68 +++++++++++++++++++++++++++++++++++------
 3 files changed, 65 insertions(+), 13 deletions(-)

diff --git a/.clang-format-ignore b/.clang-format-ignore
index c955f0ad4d5d..8d232f8c190b 100644
--- a/.clang-format-ignore
+++ b/.clang-format-ignore
@@ -1,3 +1,6 @@
+**/Pods/**
+**/build/**
+**/node_modules/**
 packages/react-native/React/I18n/FBXXHashUtils.h
 packages/react-native/ReactAndroid/src/main/jni/first-party/yogajni/**
 packages/react-native/ReactAndroid/src/main/jni/third-party/**
diff --git a/package.json b/package.json
index b5dc3eafc1ef..55a1e7842346 100644
--- a/package.json
+++ b/package.json
@@ -9,15 +9,16 @@
     "build-android": "./gradlew :packages:react-native:ReactAndroid:build",
     "build": "node ./scripts/build/build.js",
     "build-types": "node ./scripts/js-api/build-types",
-    "clang-format": "node ./scripts/clang-format.js",
     "clean": "node ./scripts/build/clean.js",
     "cxx-api-build": "python -m scripts.cxx-api.parser",
     "cxx-api-validate": "python -m scripts.cxx-api.parser --validate",
     "flow-check": "flow full-check",
     "flow": "flow",
-    "format-check": "yarn format-check-javascript",
+    "format-check": "yarn format-check-javascript && yarn format-check-cpp",
+    "format-check-cpp": "node ./scripts/clang-format.js --check",
     "format-check-javascript": "prettier --check \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
-    "format": "yarn format-javascript && yarn clang-format",
+    "format": "yarn format-javascript && yarn format-cpp",
+    "format-cpp": "node ./scripts/clang-format.js",
     "format-javascript": "prettier --write \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
     "featureflags": "yarn --cwd packages/react-native featureflags",
     "js-api-diff": "node ./scripts/js-api/diff-api-snapshot",
diff --git a/scripts/clang-format.js b/scripts/clang-format.js
index abdf8c81df45..9b7181374b19 100644
--- a/scripts/clang-format.js
+++ b/scripts/clang-format.js
@@ -10,18 +10,49 @@
 
 'use strict';
 
-const dotslash = require('fb-dotslash');
 const {spawnSync} = require('node:child_process');
 const fs = require('node:fs');
 const path = require('node:path');
 const {globSync} = require('tinyglobby');
 
 const REPO_ROOT = path.resolve(__dirname, '..');
-const CLANG_FORMAT = path.join(__dirname, 'clang-format');
+const OSS_CLANG_FORMAT_DOTSLASH = path.join(__dirname, 'clang-format');
 const GENERATED_MARKER = Buffer.from('@' + 'generated');
+const IGNORE_FILE = path.join(REPO_ROOT, '.clang-format-ignore');
 const MAX_HEADER_BYTES = 4096;
 const MAX_FILES_PER_PROCESS = 30;
 
+const SOURCE_GLOB = '**/*.{c,cc,cpp,cu,cuh,cxx,h,hh,hpp,hxx,m,mm,proto,tcc}';
+
+function findClangFormat() {
+  if (process.env.CLANG_FORMAT != null && process.env.CLANG_FORMAT !== '') {
+    return {command: process.env.CLANG_FORMAT, prefixArguments: []};
+  }
+
+  try {
+    const metaClangFormat = require('./clang-format.fb').findMetaClangFormat();
+    if (metaClangFormat != null) {
+      return metaClangFormat;
+    }
+  } catch (error) {
+    if (
+      error == null ||
+      error.code !== 'MODULE_NOT_FOUND' ||
+      !String(error.message).includes("'./clang-format.fb'")
+    ) {
+      throw error;
+    }
+  }
+
+  return {
+    command:
+      process.env.DOTSLASH != null && process.env.DOTSLASH !== ''
+        ? process.env.DOTSLASH
+        : require('fb-dotslash'),
+    prefixArguments: [OSS_CLANG_FORMAT_DOTSLASH],
+  };
+}
+
 /** @param {string} file */
 function isGenerated(file) {
   let fd;
@@ -41,16 +72,33 @@ function isGenerated(file) {
 }
 
 function main() {
+  const arguments_ = process.argv.slice(2);
+  const check = arguments_.includes('--check');
+  const clangFormat = findClangFormat();
+  const positionalArguments = arguments_.filter(
+    argument => argument !== '--check',
+  );
+  const ignore = fs
+    .readFileSync(IGNORE_FILE, 'utf8')
+    .split('\n')
+    .map(line => line.trim())
+    .filter(line => line !== '' && !line.startsWith('#'));
+  const discoveredFiles = globSync(SOURCE_GLOB, {cwd: REPO_ROOT, ignore});
   const files =
-    process.argv.length > 2
-      ? process.argv.slice(2)
-      : globSync('*/**/*.{h,cpp,m,mm}', {cwd: REPO_ROOT});
+    positionalArguments.length > 0
+      ? positionalArguments.filter(file => discoveredFiles.includes(file))
+      : discoveredFiles;
   const sourceFiles = files.filter(file => !isGenerated(file));
+  let exitStatus = 0;
 
   for (let i = 0; i < sourceFiles.length; i += MAX_FILES_PER_PROCESS) {
+    const formatterArguments = [
+      ...(check ? ['--dry-run', '--Werror'] : ['-i']),
+      ...sourceFiles.slice(i, i + MAX_FILES_PER_PROCESS),
+    ];
     const result = spawnSync(
-      dotslash,
-      [CLANG_FORMAT, '-i', ...sourceFiles.slice(i, i + MAX_FILES_PER_PROCESS)],
+      clangFormat.command,
+      [...clangFormat.prefixArguments, ...formatterArguments],
       {
         cwd: REPO_ROOT,
         stdio: 'inherit',
@@ -61,13 +109,13 @@ function main() {
       throw result.error;
     }
     if (result.signal != null) {
-      process.kill(process.pid, result.signal);
-      return;
+      throw new Error(`clang-format was terminated by ${result.signal}`);
     }
     if (result.status !== 0) {
-      process.exit(result.status ?? 1);
+      exitStatus = result.status ?? 1;
     }
   }
+  process.exitCode = exitStatus;
 }
 
 main();

From 3961cdd70476087e102d6e5cd8176fd31e7d4d87 Mon Sep 17 00:00:00 2001
From: Nicola Corti <ncor@meta.com>
Date: Fri, 11 Sep 2026 05:35:23 -0700
Subject: [PATCH 3/5] Add Kotlin to `yarn format`

Summary:
Add `yarn format-kotlin` and `yarn format-check-kotlin` using the npm `ktfmt` package and its bundled formatter jar. This adds the offline package mirror and workspace lock entry without changing existing Kotlin source formatting or Gradle configuration. The wrapper discovers a suitable JDK when available and otherwise prints environment-specific Java 17 setup guidance before skipping Kotlin.

allow-large-files: The npm package intentionally contains the upstream ktfmt executable jar so offline and public installs use the same formatter.

Changelog: [Internal]

Differential Revision: D119487612
---
 package.json             |  9 ++--
 scripts/format-kotlin.js | 81 ++++++++++++++++++++++++++++++++++++
 scripts/format-utils.js  | 88 ++++++++++++++++++++++++++++++++++++++++
 yarn.lock                |  5 +++
 4 files changed, 179 insertions(+), 4 deletions(-)
 create mode 100644 scripts/format-kotlin.js
 create mode 100644 scripts/format-utils.js

diff --git a/package.json b/package.json
index 55a1e7842346..d98b49bbff4b 100644
--- a/package.json
+++ b/package.json
@@ -14,16 +14,16 @@
     "cxx-api-validate": "python -m scripts.cxx-api.parser --validate",
     "flow-check": "flow full-check",
     "flow": "flow",
-    "format-check": "yarn format-check-javascript && yarn format-check-cpp",
+    "format-check": "yarn format-check-javascript && yarn format-check-cpp && yarn format-check-kotlin",
     "format-check-cpp": "node ./scripts/clang-format.js --check",
     "format-check-javascript": "prettier --check \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
-    "format": "yarn format-javascript && yarn format-cpp",
+    "format-check-kotlin": "node ./scripts/format-kotlin.js --check",
+    "format": "yarn format-javascript && yarn format-cpp && yarn format-kotlin",
     "format-cpp": "node ./scripts/clang-format.js",
     "format-javascript": "prettier --write \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
+    "format-kotlin": "node ./scripts/format-kotlin.js",
     "featureflags": "yarn --cwd packages/react-native featureflags",
     "js-api-diff": "node ./scripts/js-api/diff-api-snapshot",
-    "lint-kotlin-check": "./gradlew ktfmtCheck",
-    "lint-kotlin": "./gradlew ktfmtFormat",
     "lint-markdown": "markdownlint-cli2 2>&1",
     "lint": "eslint --max-warnings 0 .",
     "preinstall": "node ./scripts/try-set-hermes-compiler-prebuilt.js",
@@ -101,6 +101,7 @@
     "jest-junit": "^16.0.0",
     "jest-snapshot": "^29.7.0",
     "jsonc-parser": "2.2.1",
+    "ktfmt": "0.59.0",
     "markdownlint-cli2": "^0.17.2",
     "markdownlint-rule-relative-links": "^3.0.0",
     "memfs": "^4.38.2",
diff --git a/scripts/format-kotlin.js b/scripts/format-kotlin.js
new file mode 100644
index 000000000000..9879f9bcbf97
--- /dev/null
+++ b/scripts/format-kotlin.js
@@ -0,0 +1,81 @@
+/**
+ * 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.
+ *
+ * @noflow
+ * @format
+ */
+
+'use strict';
+
+const {findJava, warnMissingJava} = require('./format-utils');
+const {spawnSync} = require('node:child_process');
+const fs = require('node:fs');
+const path = require('node:path');
+const {globSync} = require('tinyglobby');
+
+const REPO_ROOT = path.resolve(__dirname, '..');
+const KTFMT_JAR = require.resolve('ktfmt/lib/ktfmt.jar');
+const GENERATED_MARKER = Buffer.from('@' + 'generated');
+const MINIMUM_JAVA_VERSION = 17;
+const MAX_FILES_PER_PROCESS = 100;
+const MAX_HEADER_BYTES = 4096;
+const IGNORE = [
+  '**/build/**',
+  '**/com/facebook/yoga/**',
+  '**/hermes-engine/**',
+  '**/internal/featureflags/**',
+  '**/node_modules/**',
+  '**/systeminfo/ReactNativeVersion.kt',
+];
+
+function isGenerated(file) {
+  const fd = fs.openSync(path.resolve(REPO_ROOT, file), 'r');
+  try {
+    const header = Buffer.alloc(MAX_HEADER_BYTES);
+    const bytesRead = fs.readSync(fd, header, 0, header.length, 0);
+    return header.subarray(0, bytesRead).includes(GENERATED_MARKER);
+  } finally {
+    fs.closeSync(fd);
+  }
+}
+
+function main() {
+  const check = process.argv[2] === '--check';
+  const java = findJava(MINIMUM_JAVA_VERSION);
+  if (java == null) {
+    warnMissingJava('Kotlin');
+    return;
+  }
+  const files = globSync('**/*.{kt,kts}', {
+    cwd: REPO_ROOT,
+    ignore: IGNORE,
+  }).filter(file => !isGenerated(file));
+  for (let i = 0; i < files.length; i += MAX_FILES_PER_PROCESS) {
+    const result = spawnSync(
+      java,
+      [
+        '-jar',
+        KTFMT_JAR,
+        '--do-not-remove-unused-imports',
+        ...(check ? ['--dry-run', '--set-exit-if-changed'] : []),
+        ...files.slice(i, i + MAX_FILES_PER_PROCESS),
+      ],
+      {cwd: REPO_ROOT, stdio: 'inherit'},
+    );
+    if (result.error != null) {
+      throw result.error;
+    }
+    if (result.signal != null) {
+      process.kill(process.pid, result.signal);
+      return;
+    }
+    if (result.status !== 0) {
+      process.exit(result.status ?? 1);
+    }
+  }
+}
+
+main();
diff --git a/scripts/format-utils.js b/scripts/format-utils.js
new file mode 100644
index 000000000000..7b4dac220cb3
--- /dev/null
+++ b/scripts/format-utils.js
@@ -0,0 +1,88 @@
+/**
+ * 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.
+ *
+ * @noflow
+ * @format
+ */
+
+'use strict';
+
+const {spawnSync} = require('node:child_process');
+const path = require('node:path');
+
+const REPO_ROOT = path.resolve(__dirname, '..');
+
+let metaUtils = null;
+try {
+  metaUtils = require('./format-utils.fb');
+} catch (error) {
+  if (
+    error == null ||
+    typeof error !== 'object' ||
+    error.code !== 'MODULE_NOT_FOUND' ||
+    !String(error.message).includes("'./format-utils.fb'")
+  ) {
+    throw error;
+  }
+}
+
+const IS_META_CHECKOUT = metaUtils != null;
+
+function commandVersion(command, prefixArguments = []) {
+  const result = spawnSync(command, [...prefixArguments, '--version'], {
+    encoding: 'utf8',
+    env: {...process.env, PWD: REPO_ROOT},
+  });
+  return {
+    output: `${result.stdout ?? ''}\n${result.stderr ?? ''}`,
+    status: result.status,
+  };
+}
+
+function findMetaTool(...relativePath) {
+  return metaUtils?.findMetaTool(...relativePath) ?? null;
+}
+
+function javaMajorVersion(command) {
+  const result = spawnSync(command, ['-version'], {encoding: 'utf8'});
+  const output = `${result.stdout ?? ''}\n${result.stderr ?? ''}`;
+  const version = /version "(?:1\.)?(\d+)/.exec(output);
+  return result.status === 0 && version != null ? Number(version[1]) : null;
+}
+
+function findJava(minimumVersion) {
+  if (process.env.JAVA != null && process.env.JAVA !== '') {
+    return javaMajorVersion(process.env.JAVA) >= minimumVersion
+      ? process.env.JAVA
+      : null;
+  }
+
+  const candidates = [];
+  candidates.push(...(metaUtils?.findJavaCandidates() ?? []));
+  candidates.push('java');
+
+  return (
+    candidates.find(command => javaMajorVersion(command) >= minimumVersion) ??
+    null
+  );
+}
+
+function warnMissingJava(language) {
+  const instructions =
+    metaUtils?.missingJavaInstructions() ??
+    'Please install a JDK of your choice with Java 17 or newer and make sure the `java` command is in your PATH, or set JAVA=/path/to/java.';
+  console.warn(
+    `warning: Skipping ${language} formatting because Java 17 or newer was not found.\n${instructions}`,
+  );
+}
+
+module.exports = {
+  commandVersion,
+  findJava,
+  findMetaTool,
+  IS_META_CHECKOUT,
+  warnMissingJava,
+};
diff --git a/yarn.lock b/yarn.lock
index 5126518dbbe1..3327c4cc333c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6373,6 +6373,11 @@ kleur@^3.0.3:
   resolved "https://registry.yarnpkg.com/kleur/-/kleur-3.0.3.tgz#a79c9ecc86ee1ce3fa6206d1216c501f147fc07e"
   integrity sha512-eTIzlVOSUR+JxdDFepEYcBMtZ9Qqdef+rnzWdRZuMbOywu5tO2w2N7rqjoANZ5k9vywhL6Br1VRjUIgTQx4E8w==
 
+ktfmt@0.59.0:
+  version "0.59.0"
+  resolved "https://registry.yarnpkg.com/ktfmt/-/ktfmt-0.59.0.tgz#99f98b81dbdc7f1487dfbc9850eb17b3780cf6d5"
+  integrity sha512-lOEn/7y2Ez2/nxDTn5EwJv6BSugB8BtzY2Gn6GvyLIAjdUf3xgKzirIxD57t/vu5I6eybivmVtONI3WGXyZ3lw==
+
 language-subtag-registry@^0.3.20:
   version "0.3.23"
   resolved "https://registry.yarnpkg.com/language-subtag-registry/-/language-subtag-registry-0.3.23.tgz#23529e04d9e3b74679d70142df3fd2eb6ec572e7"

From 793a8c59770ef7467cf1fb2db57be17b069ca39e Mon Sep 17 00:00:00 2001
From: Nicola Corti <ncor@meta.com>
Date: Fri, 11 Sep 2026 05:35:23 -0700
Subject: [PATCH 4/5] Remove the ktfmt Gradle plugin

Summary:
Remove the ktfmt Gradle plugin and its task wiring now that Kotlin formatting is provided by the repository npm command.

Changelog: [Internal]

Differential Revision: D119504761
---
 build.gradle.kts                              | 40 -------------------
 packages/gradle-plugin/build.gradle.kts       | 23 -----------
 .../gradle-plugin/gradle/libs.versions.toml   |  2 -
 .../build.gradle.kts                          |  1 -
 .../settings-plugin/build.gradle.kts          |  1 -
 .../shared-testutil/build.gradle.kts          |  1 -
 .../gradle-plugin/shared/build.gradle.kts     |  1 -
 .../ReactAndroid/build.gradle.kts             |  1 -
 .../react-native/gradle/libs.versions.toml    |  2 -
 9 files changed, 72 deletions(-)

diff --git a/build.gradle.kts b/build.gradle.kts
index 19fcc1df1a66..e1320dc6d06c 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -13,7 +13,6 @@ plugins {
   alias(libs.plugins.kotlin.android) apply false
   alias(libs.plugins.binary.compatibility.validator) apply true
   alias(libs.plugins.android.test) apply false
-  alias(libs.plugins.ktfmt) apply true
 }
 
 val reactAndroidProperties = java.util.Properties()
@@ -176,42 +175,3 @@ if (hermesSubstitution != null) {
     }
   }
 }
-
-ktfmt {
-  blockIndent.set(2)
-  continuationIndent.set(4)
-  maxWidth.set(100)
-  removeUnusedImports.set(false)
-  manageTrailingCommas.set(false)
-}
-
-// Configure ktfmt tasks to include gradle-plugin
-listOf("ktfmtCheck", "ktfmtFormat").forEach { taskName ->
-  tasks.named(taskName) { dependsOn(gradle.includedBuild("gradle-plugin").task(":$taskName")) }
-}
-
-allprojects {
-  // Apply exclusions for specific files that should not be formatted
-  val excludePatterns = listOf(
-      "**/build/**",
-      "**/hermes-engine/**",
-      "**/internal/featureflags/**",
-      "**/systeminfo/ReactNativeVersion.kt",
-  )
-  listOf(
-      com.ncorti.ktfmt.gradle.tasks.KtfmtCheckTask::class,
-      com.ncorti.ktfmt.gradle.tasks.KtfmtFormatTask::class,
-  )
-      .forEach { tasks.withType(it) { exclude(excludePatterns) } }
-
-  // Disable the problematic ktfmt script tasks due to symbolic link issues in subprojects
-  afterEvaluate {
-    listOf("ktfmtCheckScripts", "ktfmtFormatScripts").forEach {
-      tasks.findByName(it)?.enabled = false
-    }
-  }
-}
-
-// We intentionally disable the `ktfmtCheck` tasks as the formatting is primarly handled inside
-// fbsource
-allprojects { tasks.withType<com.ncorti.ktfmt.gradle.tasks.KtfmtCheckTask>() { enabled = false } }
diff --git a/packages/gradle-plugin/build.gradle.kts b/packages/gradle-plugin/build.gradle.kts
index 80021f061fb7..48ecd29695e8 100644
--- a/packages/gradle-plugin/build.gradle.kts
+++ b/packages/gradle-plugin/build.gradle.kts
@@ -7,7 +7,6 @@
 
 plugins {
   alias(libs.plugins.kotlin.jvm).apply(false)
-  alias(libs.plugins.ktfmt).apply(true)
 }
 
 tasks.register("build") {
@@ -27,25 +26,3 @@ tasks.register("clean") {
       ":shared:clean",
   )
 }
-
-tasks.named("ktfmtCheck") {
-  dependsOn(
-      ":react-native-gradle-plugin:ktfmtCheck",
-      ":settings-plugin:ktfmtCheck",
-      ":shared-testutil:ktfmtCheck",
-      ":shared:ktfmtCheck",
-  )
-}
-
-tasks.named("ktfmtFormat") {
-  dependsOn(
-      ":react-native-gradle-plugin:ktfmtFormat",
-      ":settings-plugin:ktfmtFormat",
-      ":shared-testutil:ktfmtFormat",
-      ":shared:ktfmtFormat",
-  )
-}
-
-// We intentionally disable the `ktfmtCheck` tasks as the formatting is primarly handled inside
-// fbsource
-allprojects { tasks.withType<com.ncorti.ktfmt.gradle.tasks.KtfmtCheckTask>() { enabled = false } }
diff --git a/packages/gradle-plugin/gradle/libs.versions.toml b/packages/gradle-plugin/gradle/libs.versions.toml
index 65dd0b10f53f..8446ff11b096 100644
--- a/packages/gradle-plugin/gradle/libs.versions.toml
+++ b/packages/gradle-plugin/gradle/libs.versions.toml
@@ -6,7 +6,6 @@ javapoet = "1.13.0"
 junit = "4.13.2"
 kotlin = "2.2.0"
 assertj = "3.25.1"
-ktfmt = "0.22.0"
 
 [libraries]
 kotlin-gradle-plugin = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin" }
@@ -19,4 +18,3 @@ assertj = { module = "org.assertj:assertj-core", version.ref = "assertj" }
 
 [plugins]
 kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
-ktfmt = { id = "com.ncorti.ktfmt.gradle", version.ref = "ktfmt" }
diff --git a/packages/gradle-plugin/react-native-gradle-plugin/build.gradle.kts b/packages/gradle-plugin/react-native-gradle-plugin/build.gradle.kts
index 1450a701a71a..1f083f522185 100644
--- a/packages/gradle-plugin/react-native-gradle-plugin/build.gradle.kts
+++ b/packages/gradle-plugin/react-native-gradle-plugin/build.gradle.kts
@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
   alias(libs.plugins.kotlin.jvm)
-  alias(libs.plugins.ktfmt)
   id("java-gradle-plugin")
 }
 
diff --git a/packages/gradle-plugin/settings-plugin/build.gradle.kts b/packages/gradle-plugin/settings-plugin/build.gradle.kts
index 39a1e490d4aa..15b8ed13087f 100644
--- a/packages/gradle-plugin/settings-plugin/build.gradle.kts
+++ b/packages/gradle-plugin/settings-plugin/build.gradle.kts
@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
   alias(libs.plugins.kotlin.jvm)
-  alias(libs.plugins.ktfmt)
   id("java-gradle-plugin")
 }
 
diff --git a/packages/gradle-plugin/shared-testutil/build.gradle.kts b/packages/gradle-plugin/shared-testutil/build.gradle.kts
index 34591e06e8c5..658759c3ea17 100644
--- a/packages/gradle-plugin/shared-testutil/build.gradle.kts
+++ b/packages/gradle-plugin/shared-testutil/build.gradle.kts
@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
   alias(libs.plugins.kotlin.jvm)
-  alias(libs.plugins.ktfmt)
 }
 
 repositories { mavenCentral() }
diff --git a/packages/gradle-plugin/shared/build.gradle.kts b/packages/gradle-plugin/shared/build.gradle.kts
index 0f62f3310afc..492f47325556 100644
--- a/packages/gradle-plugin/shared/build.gradle.kts
+++ b/packages/gradle-plugin/shared/build.gradle.kts
@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
   alias(libs.plugins.kotlin.jvm)
-  alias(libs.plugins.ktfmt)
 }
 
 repositories { mavenCentral() }
diff --git a/packages/react-native/ReactAndroid/build.gradle.kts b/packages/react-native/ReactAndroid/build.gradle.kts
index 8a27e3e4f470..39e5e642a5e7 100644
--- a/packages/react-native/ReactAndroid/build.gradle.kts
+++ b/packages/react-native/ReactAndroid/build.gradle.kts
@@ -18,7 +18,6 @@ plugins {
   id("com.facebook.react")
   alias(libs.plugins.android.library)
   alias(libs.plugins.download)
-  alias(libs.plugins.ktfmt)
 }
 
 version = project.findProperty("VERSION_NAME")?.toString()!!
diff --git a/packages/react-native/gradle/libs.versions.toml b/packages/react-native/gradle/libs.versions.toml
index 0bba9087d8dc..0c84940db453 100644
--- a/packages/react-native/gradle/libs.versions.toml
+++ b/packages/react-native/gradle/libs.versions.toml
@@ -31,7 +31,6 @@ jsc-android = "2026004.0.1"
 jsr305 = "3.0.2"
 junit = "4.13.2"
 kotlin = "2.2.0"
-ktfmt = "0.22.0"
 mockito = "3.12.4"
 mockito-kotlin = "3.2.0"
 nexus-publish = "2.0.0"
@@ -97,7 +96,6 @@ thoughtworks = {module = "com.thoughtworks.xstream:xstream", version.ref = "xstr
 android-application = { id = "com.android.application", version.ref = "agp" }
 android-library = { id = "com.android.library", version.ref = "agp" }
 download = { id = "de.undercouch.download", version.ref = "download" }
-ktfmt = { id = "com.ncorti.ktfmt.gradle", version.ref = "ktfmt" }
 nexus-publish = { id = "io.github.gradle-nexus.publish-plugin", version.ref = "nexus-publish" }
 kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
 binary-compatibility-validator = { id = "org.jetbrains.kotlinx.binary-compatibility-validator", version.ref = "binary-compatibility-validator" }

From 554ee9c6b219523d87cf99d311111b7eeab32ae0 Mon Sep 17 00:00:00 2001
From: Nicola Corti <ncor@meta.com>
Date: Fri, 11 Sep 2026 05:42:15 -0700
Subject: [PATCH 5/5] Add Java to `yarn format` (#58466)

Summary:
Pull Request resolved: https://github.com/react/react-native/pull/58466

Add `yarn format-java` and `yarn format-check-java` using the npm `google-java-format` package, which bundles google-java-format 1.23.0. This removes the Gradle build dependency and adds the offline package mirror and workspace lock entries. The wrapper discovers a suitable JDK when available and otherwise prints environment-specific Java 17 setup guidance before skipping Java.

Changelog: [Internal]

Reviewed By: javache

Differential Revision: D119487613
---
 package.json           |   7 ++-
 scripts/format-java.js | 106 +++++++++++++++++++++++++++++++++++++++++
 yarn.lock              |  49 +++++++++++++++++++
 3 files changed, 160 insertions(+), 2 deletions(-)
 create mode 100644 scripts/format-java.js

diff --git a/package.json b/package.json
index d98b49bbff4b..9880d40688a4 100644
--- a/package.json
+++ b/package.json
@@ -14,12 +14,14 @@
     "cxx-api-validate": "python -m scripts.cxx-api.parser --validate",
     "flow-check": "flow full-check",
     "flow": "flow",
-    "format-check": "yarn format-check-javascript && yarn format-check-cpp && yarn format-check-kotlin",
+    "format-check": "yarn format-check-javascript && yarn format-check-cpp && yarn format-check-kotlin && yarn format-check-java",
     "format-check-cpp": "node ./scripts/clang-format.js --check",
+    "format-check-java": "node ./scripts/format-java.js --check",
     "format-check-javascript": "prettier --check \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
     "format-check-kotlin": "node ./scripts/format-kotlin.js --check",
-    "format": "yarn format-javascript && yarn format-cpp && yarn format-kotlin",
+    "format": "yarn format-javascript && yarn format-cpp && yarn format-kotlin && yarn format-java",
     "format-cpp": "node ./scripts/clang-format.js",
+    "format-java": "node ./scripts/format-java.js",
     "format-javascript": "prettier --write \"./**/*.{cjs,cts,flow,js,jsx,md,mjs,mts,ts,tsx,yaml,yml}\"",
     "format-kotlin": "node ./scripts/format-kotlin.js",
     "featureflags": "yarn --cwd packages/react-native featureflags",
@@ -93,6 +95,7 @@
     "flow-eslint": "0.331.0",
     "flow-parser": "0.331.0",
     "flow-transform": "0.331.0",
+    "google-java-format": "1.4.0",
     "ini": "^5.0.0",
     "inquirer": "^7.1.0",
     "jest": "^29.7.0",
diff --git a/scripts/format-java.js b/scripts/format-java.js
new file mode 100644
index 000000000000..d991b6b38922
--- /dev/null
+++ b/scripts/format-java.js
@@ -0,0 +1,106 @@
+/**
+ * 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.
+ *
+ * @noflow
+ * @format
+ */
+
+'use strict';
+
+const {findJava, warnMissingJava} = require('./format-utils');
+const {spawnSync} = require('node:child_process');
+const fs = require('node:fs');
+const path = require('node:path');
+const {globSync} = require('tinyglobby');
+
+const REPO_ROOT = path.resolve(__dirname, '..');
+const GENERATED_MARKER = Buffer.from('@' + 'generated');
+const MINIMUM_JAVA_VERSION = 17;
+const MAX_FILES_PER_PROCESS = 30;
+const MAX_HEADER_BYTES = 4096;
+const IGNORE = [
+  '**/Pods/**',
+  '**/build/**',
+  '**/com/facebook/yoga/**',
+  '**/node_modules/**',
+];
+
+function isGenerated(file) {
+  let fd;
+  try {
+    fd = fs.openSync(path.resolve(REPO_ROOT, file), 'r');
+    const header = Buffer.alloc(MAX_HEADER_BYTES);
+    const bytesRead = fs.readSync(fd, header, 0, header.length, 0);
+    return header.subarray(0, bytesRead).includes(GENERATED_MARKER);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    throw new Error(`Unable to inspect ${file}: ${message}`, {cause: error});
+  } finally {
+    if (fd != null) {
+      fs.closeSync(fd);
+    }
+  }
+}
+
+function findGoogleJavaFormatJar() {
+  const packageRoot = path.dirname(
+    require.resolve('google-java-format/package.json'),
+  );
+  const jars = fs
+    .readdirSync(path.join(packageRoot, 'lib'))
+    .filter(file => file.endsWith('-all-deps.jar'));
+  if (jars.length !== 1) {
+    throw new Error(
+      `Expected one google-java-format jar, found ${jars.length}.`,
+    );
+  }
+  return path.join(packageRoot, 'lib', jars[0]);
+}
+
+function main() {
+  const check = process.argv[2] === '--check';
+  const java = findJava(MINIMUM_JAVA_VERSION);
+  if (java == null) {
+    warnMissingJava('Java');
+    return;
+  }
+  const googleJavaFormatJar = findGoogleJavaFormatJar();
+  const files = globSync('**/*.java', {cwd: REPO_ROOT, ignore: IGNORE}).filter(
+    file => !isGenerated(file),
+  );
+
+  let exitStatus = 0;
+  for (let i = 0; i < files.length; i += MAX_FILES_PER_PROCESS) {
+    const result = spawnSync(
+      java,
+      [
+        '--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED',
+        '--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED',
+        '--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED',
+        '--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED',
+        '--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED',
+        '--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED',
+        '-jar',
+        googleJavaFormatJar,
+        ...(check ? ['--dry-run', '--set-exit-if-changed'] : ['--replace']),
+        ...files.slice(i, i + MAX_FILES_PER_PROCESS),
+      ],
+      {cwd: REPO_ROOT, stdio: 'inherit'},
+    );
+    if (result.error != null) {
+      throw result.error;
+    }
+    if (result.signal != null) {
+      throw new Error(`google-java-format was terminated by ${result.signal}`);
+    }
+    if (result.status !== 0) {
+      exitStatus = result.status ?? 1;
+    }
+  }
+  process.exitCode = exitStatus;
+}
+
+main();
diff --git a/yarn.lock b/yarn.lock
index 3327c4cc333c..ff0546f73995 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2912,6 +2912,11 @@ async-limiter@~1.0.0:
   resolved "https://registry.yarnpkg.com/async-limiter/-/async-limiter-1.0.1.tgz#dd379e94f0db8310b08291f9d64c3209766617fd"
   integrity sha512-csOlWGAcRFJaI6m+F2WKdnMKr4HhdhFVBk0H/QbJFMCr+uO2kwohwXQPxw/9OCxp05r5ghVBFSyioixx3gfkNQ==
 
+async@^3.2.4:
+  version "3.2.6"
+  resolved "https://registry.yarnpkg.com/async/-/async-3.2.6.tgz#1b0728e14929d51b85b449b7f06e27c1145e38ce"
+  integrity sha512-htCUDlxyyCLMgaM3xXg0C0LW2xqfuQ6p05pCEIsXuyQ+a1koYKTuBMzRNwmybfLgvJDMd0r1LTn4+E0Ti6C2AA==
+
 author-regex@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/author-regex/-/author-regex-1.0.0.tgz#d08885be6b9bbf9439fe087c76287245f0a81450"
@@ -3146,6 +3151,13 @@ brace-expansion@^1.1.7:
     balanced-match "^1.0.0"
     concat-map "0.0.1"
 
+brace-expansion@^2.0.1:
+  version "2.1.4"
+  resolved "https://registry.yarnpkg.com/brace-expansion/-/brace-expansion-2.1.4.tgz#589dab11c0018d0366be64cd8bf12c8dbecc8326"
+  integrity sha512-hGfVzPxthbf3+2yjg/RBs60cB0FhqBS/zvdV/4wn4/BmN0bNMMHPc4V/BbFieqf1TKAGGAHnY4eSjajCl0f2Xg==
+  dependencies:
+    balanced-match "^1.0.0"
+
 brace-expansion@^2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/brace-expansion/-/brace-expansion-2.0.2.tgz#54fc53237a613d854c7bd37463aad17df87214e7"
@@ -5041,6 +5053,17 @@ glob@^7.0.0, glob@^7.1.3, glob@^7.1.4:
     once "^1.3.0"
     path-is-absolute "^1.0.0"
 
+glob@^8.1.0:
+  version "8.1.0"
+  resolved "https://registry.yarnpkg.com/glob/-/glob-8.1.0.tgz#d388f656593ef708ee3e34640fdfb99a9fd1c33e"
+  integrity sha512-r8hpEjiQEYlF2QU0df3dS+nxxSIreXQS1qRhMJM0Q5NDdR386C7jb7Hwwod8Fgiuex+k0GFjgft18yvxm5XoCQ==
+  dependencies:
+    fs.realpath "^1.0.0"
+    inflight "^1.0.4"
+    inherits "2"
+    minimatch "^5.0.1"
+    once "^1.3.0"
+
 globals@^11.1.0:
   version "11.12.0"
   resolved "https://registry.yarnpkg.com/globals/-/globals-11.12.0.tgz#ab8795338868a0babd8525758018c2a7eb95c42e"
@@ -5085,6 +5108,15 @@ globby@^11.1.0:
     merge2 "^1.4.1"
     slash "^3.0.0"
 
+google-java-format@1.4.0:
+  version "1.4.0"
+  resolved "https://registry.yarnpkg.com/google-java-format/-/google-java-format-1.4.0.tgz#d944b7a20f0a3729318b5c120931178843ed9a82"
+  integrity sha512-TlO1nUogUW6PonVL4xZCciVoJcjB2Nxo/dEY5M8GC5TJnQi6A4XeqJoiOot/To20350wPup9aQfP3Ia6GR+vEg==
+  dependencies:
+    async "^3.2.4"
+    glob "^8.1.0"
+    resolve "^1.22.8"
+
 gopd@^1.0.1, gopd@^1.2.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/gopd/-/gopd-1.2.0.tgz#89f56b8217bdbc8802bd299df6d7f1081d7e51a1"
@@ -7220,6 +7252,13 @@ minimatch@^10.0.1, minimatch@^10.2.2:
   dependencies:
     brace-expansion "^5.0.5"
 
+minimatch@^5.0.1:
+  version "5.1.9"
+  resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-5.1.9.tgz#1293ef15db0098b394540e8f9f744f9fda8dee4b"
+  integrity sha512-7o1wEA2RyMP7Iu7GNba9vc0RWWGACJOCZBJX2GJWip0ikV+wcOsgVuY9uE8CPiyQhkGFSlhuSkZPavN7u1c2Fw==
+  dependencies:
+    brace-expansion "^2.0.1"
+
 minimatch@^9.0.4:
   version "9.0.9"
   resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-9.0.9.tgz#9b0cb9fcb78087f6fd7eababe2511c4d3d60574e"
@@ -8080,6 +8119,16 @@ resolve@^1.1.6, resolve@^1.14.2, resolve@^1.20.0, resolve@~1.22.1, resolve@~1.22
     path-parse "^1.0.7"
     supports-preserve-symlinks-flag "^1.0.0"
 
+resolve@^1.22.8:
+  version "1.22.12"
+  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.22.12.tgz#f5b2a680897c69c238a13cd16b15671f8b73549f"
+  integrity sha512-TyeJ1zif53BPfHootBGwPRYT1RUt6oGWsaQr8UyZW/eAm9bKoijtvruSDEmZHm92CwS9nj7/fWttqPCgzep8CA==
+  dependencies:
+    es-errors "^1.3.0"
+    is-core-module "^2.16.1"
+    path-parse "^1.0.7"
+    supports-preserve-symlinks-flag "^1.0.0"
+
 resolve@^2.0.0-next.5:
   version "2.0.0-next.5"
   resolved "https://registry.yarnpkg.com/resolve/-/resolve-2.0.0-next.5.tgz#6b0ec3107e671e52b68cd068ef327173b90dc03c"