Add Kotlin to yarn format (#58462)

Summary:
Pull Request resolved: https://github.com/react/react-native/pull/58462

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]

Reviewed By: javache

Differential Revision: D119487612

fbshipit-source-id: cb699a1286cffbf461ef69ed66f694e3f69415d0

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",

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();

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,
+};

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"