Add java-ast-refactoring skill (#3064)

This adds a Gemini CLI skill that leverages OpenRewrite to perform Abstract Syntax Tree (AST) based refactoring on Java codebases. It is highly preferred over text-based regex or python scripts because it understands Java semantics, correctly updates imports, and preserves formatting. A custom Python script is also included as a fallback for renaming fields and local variables.
2026-08-22 07:06:10 +00:00 · 2026-05-27 18:33:38 +00:00
parent ba91141505
commit ad992beff9
4 changed files with 263 additions and 0 deletions
@@ -0,0 +1,87 @@
+#!/bin/bash
+# Copyright 2026 The Nomulus Authors. All Rights Reserved.
+#
+# 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.
+
+# Wrapper script to dynamically execute OpenRewrite without modifying build.gradle
+
+if [ -z "$1" ]; then
+  echo "Usage: $0 <path-to-rewrite.yml>"
+  exit 1
+fi
+
+RECIPE_FILE=$(realpath "$1")
+if [ ! -f "$RECIPE_FILE" ]; then
+  echo "Error: Recipe file $RECIPE_FILE not found."
+  exit 1
+fi
+
+# Extract the name of the recipe from the YAML to activate it
+RECIPE_NAME=$(grep -oP '(?<=name: ).*' "$RECIPE_FILE" | head -n 1)
+
+if [ -z "$RECIPE_NAME" ]; then
+  echo "Error: Could not extract 'name:' from $RECIPE_FILE"
+  exit 1
+fi
+
+INIT_SCRIPT="rewrite-init.gradle"
+
+cat << EOF > "$INIT_SCRIPT"
+initscript {
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+    }
+    dependencies {
+        classpath("org.openrewrite.rewrite:org.openrewrite.rewrite.gradle.plugin:7.33.0")
+    }
+}
+
+rootProject {
+    apply plugin: org.openrewrite.gradle.RewritePlugin
+
+    rewrite {
+        activeRecipe("$RECIPE_NAME")
+    }
+
+    dependencies {
+        rewrite("org.openrewrite.recipe:rewrite-testing-frameworks:2.14.0")
+        rewrite("org.openrewrite.recipe:rewrite-migrate-java:2.11.0")
+        rewrite("org.openrewrite.recipe:rewrite-spring:5.7.0")
+    }
+}
+
+allprojects {
+    apply plugin: org.openrewrite.gradle.RewritePlugin
+}
+EOF
+
+# Copy the recipe file to the workspace root temporarily so OpenRewrite finds it
+cp "$RECIPE_FILE" ./rewrite.yml
+
+echo "Executing OpenRewrite recipe: $RECIPE_NAME"
+./gradlew --init-script "$INIT_SCRIPT" rewriteRun --no-parallel --no-configuration-cache
+
+echo "Running code formatters to fix Checkstyle line-length and import ordering..."
+./gradlew spotlessApply
+
+# Automatically handle line-wrapping and formatting for all files modified by OpenRewrite
+MODIFIED_JAVA_FILES=$(git diff --name-only --diff-filter=d | grep "\.java$" || true)
+if [ -n "$MODIFIED_JAVA_FILES" ]; then
+  echo "Applying google-java-format to all modified Java files to enforce LineLength..."
+  echo "$MODIFIED_JAVA_FILES" | xargs -r google-java-format --replace
+fi
+
+# Clean up temporary files
+rm "$INIT_SCRIPT"
+rm ./rewrite.yml
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+# Copyright 2026 The Nomulus Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+import re
+import os
+
+def usage():
+    print("Usage: python safe_rename.py <filepath> <old_name> <new_name>")
+    print("Safely renames an identifier in a Java file, ignoring strings and comments.")
+    sys.exit(1)
+
+def main():
+    if len(sys.argv) < 4:
+        usage()
+
+    filepath = sys.argv[1]
+    old_name = sys.argv[2]
+    new_name = sys.argv[3]
+
+    if not os.path.exists(filepath):
+        print(f"Error: File {filepath} not found.")
+        sys.exit(1)
+
+    with open(filepath, 'r', encoding='utf-8') as f:
+        content = f.read()
+
+    # Regex to tokenize Java source safely.
+    token_pattern = re.compile(
+        r'(?P<string>"(?:\\.|[^"\\])*")|'
+        r'(?P<char>\'(?:\\.|[^\'\\])*\')|'
+        r'(?P<line_comment>//.*)|'
+        r'(?P<block_comment>/\*[\s\S]*?\*/)|'
+        r'(?P<ident>[a-zA-Z_$][a-zA-Z0-9_$]*)'
+    )
+
+    def replacer(match):
+        if match.group('ident') == old_name:
+            return new_name
+        return match.group(0)
+
+    new_content = token_pattern.sub(replacer, content)
+
+    if content == new_content:
+        print(f"No occurrences of '{old_name}' found to rename in {filepath}.")
+    else:
+        with open(filepath, 'w', encoding='utf-8') as f:
+            f.write(new_content)
+        print(f"Successfully renamed '{old_name}' to '{new_name}' in {filepath}.")
+
+if __name__ == '__main__':
+    main()