Finish GraalVM native-image support

.gitattributes

@@ -0,0 +1,4 @@
+# GraalVM native-image reachability metadata is generated by the tracing agent (see core/README.md
+# and regenerate_native_metadata.sh). Mark it generated so code review collapses the diff and it's
+# excluded from language stats.
+core/src/main/native-image/resources/**/*.json linguist-generated=true

.github/workflows/build_and_test.yml

@@ -4,6 +4,8 @@ on:
   push:
     paths-ignore:
       - '**.md'
+    branches:
+      - main
   pull_request:
     paths-ignore:
       - '**.md'
@@ -31,3 +33,56 @@ jobs:
       run: ./gradlew :lambda:build --stacktrace --no-daemon
     - name: Build ktfmt
       run: ./gradlew :ktfmt:build --stacktrace --no-daemon
+
+  native:
+    # The linux build is blocking so stale GraalVM reachability metadata (which is OS-independent)
+    # fails CI. macOS and Windows stay non-blocking, since cross-platform toolchain hiccups
+    # shouldn't fail the run. Release binaries are built separately (publish_artifacts_on_release.yaml).
+    # Linux uses the oldest available ubuntu for broader glibc compatibility.
+    name: Native Image on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    continue-on-error: ${{ matrix.os != 'ubuntu-22.04' }}
+    # On Windows runners the workspace is on D: but java.io.tmpdir defaults to C:. native-build-tools
+    # writes the native-image @argfile under java.io.tmpdir, then relativizes it against the build's
+    # working directory (on D:), which fails with "'other' has different root". Point temp at the
+    # workspace drive so both share a root. Empty (no-op) on other OSes.
+    env:
+      TMP: ${{ matrix.os == 'windows-latest' && format('{0}\tmp', github.workspace) || '' }}
+      TEMP: ${{ matrix.os == 'windows-latest' && format('{0}\tmp', github.workspace) || '' }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-22.04, macos-latest, windows-latest]
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: recursive
+
+    - name: Create temp dir on workspace drive (Windows)
+      if: matrix.os == 'windows-latest'
+      run: New-Item -ItemType Directory -Force -Path "${{ github.workspace }}\tmp"
+
+    # Gradle runs on the project's JDK (17); native-image is provided separately via GRAALVM_HOME
+    # (set-java-home: false keeps JAVA_HOME pointed at the JDK above).
+    - name: Set up JDK 17
+      uses: actions/setup-java@v4
+      with:
+        java-version: 17
+        distribution: zulu
+
+    - name: Set up GraalVM
+      uses: graalvm/setup-graalvm@v1
+      with:
+        java-version: '25'
+        distribution: 'graalvm-community'
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        set-java-home: 'false'
+        native-image-job-reports: 'true'
+
+    - name: Build
+      shell: bash
+      run: ./gradlew :ktfmt:nativeCompile --stacktrace --no-daemon
+
+    - name: Smoke test
+      shell: bash
+      run: ./native_smoke_test.sh

.github/workflows/publish_artifacts_on_release.yaml

@@ -83,6 +83,76 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
+  # Build the GraalVM native binary per platform and attach it to the GitHub Release. Modeled on
+  # google-java-format's release workflow. Uses GraalVM Community (Serial GC only, which matches the
+  # build's default) so there are no Oracle GraalVM licensing considerations.
+  upload_native_binaries:
+    name: Native binary (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    permissions:
+      contents: write  # Required to upload release assets
+    strategy:
+      fail-fast: false
+      matrix:
+        # Build linux on the oldest available ubuntu for broader glibc compatibility. Keep the keys
+        # of the SUFFIX map below in sync with this list.
+        os: [ubuntu-22.04, ubuntu-22.04-arm, macos-latest, windows-latest]
+    env:
+      SUFFIX: ${{ fromJson('{"ubuntu-22.04":"linux-x86-64","ubuntu-22.04-arm":"linux-arm64","macos-latest":"darwin-arm64","windows-latest":"windows-x86-64"}')[matrix.os] }}
+      EXTENSION: ${{ matrix.os == 'windows-latest' && '.exe' || '' }}
+      # On Windows the workspace is on D: but java.io.tmpdir defaults to C:. native-build-tools writes
+      # the native-image @argfile under java.io.tmpdir, then relativizes it against the build's working
+      # directory (on D:), which fails with "'other' has different root". Point temp at the workspace
+      # drive so both share a root. Empty (no-op) on other OSes.
+      TMP: ${{ matrix.os == 'windows-latest' && format('{0}\tmp', github.workspace) || '' }}
+      TEMP: ${{ matrix.os == 'windows-latest' && format('{0}\tmp', github.workspace) || '' }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.events.release.tag_name || inputs.release_tag || github.ref }}
+
+      - name: Create temp dir on workspace drive (Windows)
+        if: matrix.os == 'windows-latest'
+        run: New-Item -ItemType Directory -Force -Path "${{ github.workspace }}\tmp"
+
+      # Gradle runs on JDK 17; native-image is provided via GRAALVM_HOME (set-java-home: false).
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: 17
+          distribution: zulu
+
+      - name: Set up GraalVM
+        uses: graalvm/setup-graalvm@v1
+        with:
+          java-version: '25'
+          distribution: 'graalvm-community'
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          set-java-home: 'false'
+          native-image-job-reports: 'true'
+
+      - name: Build native binary
+        shell: bash
+        run: ./gradlew :ktfmt:nativeCompile -Pktfmt.native.release=true --stacktrace --no-daemon
+
+      - name: Smoke test
+        shell: bash
+        run: ./native_smoke_test.sh
+
+      - name: Stage binary
+        shell: bash
+        run: |
+          mkdir -p release
+          cp "core/build/native/nativeCompile/ktfmt${EXTENSION}" "release/ktfmt_${SUFFIX}${EXTENSION}"
+
+      - name: Upload native binary to GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ github.events.release.tag_name || inputs.release_tag }}
+          files: release/ktfmt_${{ env.SUFFIX }}${{ env.EXTENSION }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
   deploy_website:
     runs-on: ubuntu-latest
     steps:

.gitignore

@@ -25,3 +25,7 @@ release-ktfmt-website/
 **/build/
 !src/**/build/
 .claude/
+
+# Native Image profiles are large
+core/src/main/native-image/profiles/*.iprof
+

CHANGELOG.md

@@ -19,6 +19,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 - Remove forced breaking of `context` function types (https://github.com/facebook/ktfmt/pull/613)
 - Preserve user-authored line breaks inside lambda bodies by default, rather than have ktfmt impose anything. This can be particularly useful for DSL syntax like Compose UI or Kotlin Gradle script. The behavior follows the `FormattingOptions.preserveLambdaBreaks` setting of the chosen style. (https://github.com/facebook/ktfmt/pull/614)
 - Add a `FormattingOptions.Builder` API for tools to avoid breaking ABI changes with new options. (https://github.com/facebook/ktfmt/pull/614)
+- Add standalone native binaries built with GraalVM `native-image`. These have identical CLI behavior to the JVM version but with near-instant startup and no JVM required (https://github.com/facebook/ktfmt/issues/441)
 
 ## [0.62]
 ### Added

README.md

@@ -115,6 +115,32 @@ val state = remember { mutableStateOf(false) }
 or limited `.editorconfig` support). This is a deliberate design decision to unify our code formatting on a
 single format.*
 
+### Native binary
+
+`ktfmt` is also available as a standalone native binary, compiled ahead-of-time with
+[GraalVM `native-image`](https://www.graalvm.org/latest/reference-manual/native-image/). It behaves
+exactly like the JVM CLI (same options) but starts near-instantly and needs no JVM installed, which
+is especially handy for pre-commit hooks and formatting only changed files. Pre-built binaries for
+each supported platform are attached to the [releases page](https://github.com/facebook/ktfmt/releases):
+
+```
+$ ktfmt [--kotlinlang-style | --google-style] [files...]
+```
+
+#### Building the native binary from source
+
+Building requires a [GraalVM](https://www.graalvm.org/downloads/) JDK (one that includes
+`native-image`) discoverable via `GRAALVM_HOME` or `PATH`:
+
+```
+$ ./gradlew :ktfmt:nativeCompile
+$ ./core/build/native/nativeCompile/ktfmt --version
+```
+
+The build defaults to the Serial GC and a broadly-compatible `-march` target. Several knobs are
+exposed via `-Pktfmt.native.*` properties (GC, target architecture, PGO, static linking, …); see
+[`build-logic/src/main/kotlin/ktfmt.native-image.gradle.kts`](build-logic/src/main/kotlin/ktfmt.native-image.gradle.kts).
+
 ### using Gradle
 
 A [Gradle plugin (ktfmt-gradle)](https://github.com/cortinico/ktfmt-gradle) is available on the

build-logic/build.gradle.kts

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+plugins { `kotlin-dsl` }
+
+repositories {
+  gradlePluginPortal()
+  mavenCentral()
+}
+
+dependencies {
+  // Makes the GraalVM Native Build Tools plugin (and its `graalvmNative` DSL) available to the
+  // convention plugins defined in this build. Version is read from the shared catalog.
+  implementation(
+    libs.plugins.graalvm.get().run { "$pluginId:$pluginId.gradle.plugin:$version" }
+  )
+}

build-logic/settings.gradle.kts

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+dependencyResolutionManagement {
+  repositories {
+    gradlePluginPortal()
+    mavenCentral()
+  }
+  versionCatalogs {
+    create("libs") {
+      from(files("../gradle/libs.versions.toml"))
+      // The shared catalog declares a `ktfmt` library whose version is injected at runtime by the
+      // root build's settings. Supply a placeholder so the catalog validates when consumed here;
+      // the `ktfmt` library itself is never used by build-logic.
+      version("ktfmt", "0.0.0")
+    }
+  }
+}
+
+rootProject.name = "build-logic"