Add AddNullMethodArgument recipe

rewrite-java-test/src/test/java/org/openrewrite/java/AddNullMethodArgumentTest.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2024 the original author or authors.
+ * <p>
+ * 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
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.
+ */
+package org.openrewrite.java;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+
+class AddNullMethodArgumentTest implements RewriteTest {
+
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.parser(JavaParser.fromJavaVersion().dependsOn("""
+          class B {
+             static void foo() {}
+             static void foo(Integer n) {}
+             static void foo(Integer n1, Integer n2) {}
+             static void foo(Integer n1, Integer n2, Integer n3) {}
+             static void foo(Integer n1, Integer n2, Integer n3, Integer n4) {}
+             static void foo(Integer n1, Integer n2, Integer n3, String n4) {}
+             B() {}
+             B(Integer n) {}
+          }
+          """));
+    }
+
+    @Test
+    void addToMiddleArgument() {
+        rewriteRun(
+          spec -> spec.recipe(new AddNullMethodArgument("B foo(Integer, Integer)", 1, "java.lang.Integer", "n2", false)),
+          java(
+            "class A {{ B.foo(0, 1); }}",
+            "class A {{ B.foo(0, null, 1); }}"
+          )
+        );
+    }
+
+    @Test
+    void addArgumentsConsecutively() {
+        rewriteRun(
+          spec -> spec.recipes(
+            new AddNullMethodArgument("B foo(Integer)", 1, "java.lang.Integer", "n2", false),
+            new AddNullMethodArgument("B foo(Integer, Integer)", 1, "java.lang.Integer", "n2", false)
+          ),
+          java(
+            "class A {{ B.foo(0); }}",
+            "class A {{ B.foo(0, null, null); }}"
+          )
+        );
+    }
+
+    @Test
+    void addToConstructorArgument() {
+        rewriteRun(
+          spec -> spec.recipe(new AddNullMethodArgument("B <constructor>()", 0, "java.lang.Integer", "arg", false)),
+          java(
+            "class A { B b = new B(); }",
+            "class A { B b = new B(null); }"
+          )
+        );
+    }
+
+    @Test
+    void addCastToConflictingArgumentType() {
+        rewriteRun(
+          spec -> spec.recipe(new AddNullMethodArgument("B foo(Integer,Integer,Integer)", 3, "java.lang.String", "n2", true)),
+          java(
+            "class A {{ B.foo(0, 1, 2); }}",
+            "class A {{ B.foo(0, 1, 2, (java.lang.String) null); }}"
+          )
+        );
+    }
+
+}

rewrite-java/src/main/java/org/openrewrite/java/AddNullMethodArgument.java

@@ -0,0 +1,149 @@
+/*
+ * Copyright 2024 the original author or authors.
+ * <p>
+ * 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
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.
+ */
+package org.openrewrite.java;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.openrewrite.*;
+import org.openrewrite.internal.ListUtils;
+import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.search.UsesMethod;
+import org.openrewrite.java.tree.*;
+import org.openrewrite.marker.Markers;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.openrewrite.Tree.randomId;
+import static org.openrewrite.java.tree.Space.EMPTY;
+
+/**
+ * This recipe finds method invocations matching a method pattern and uses a zero-based argument index to determine
+ * which argument is added with a null value.
+ */
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class AddNullMethodArgument extends Recipe {
+
+    /**
+     * A method pattern that is used to find matching method invocations.
+     * See {@link  MethodMatcher} for details on the expression's syntax.
+     */
+    @Option(displayName = "Method pattern",
+            description = "A method pattern that is used to find matching method invocations.",
+            example = "com.yourorg.A foo(int, int)")
+    String methodPattern;
+
+    /**
+     * A zero-based index that indicates which argument will be added as null to the method invocation.
+     */
+    @Option(displayName = "Argument index",
+            description = "A zero-based index that indicates which argument will be added as null to the method invocation.",
+            example = "0")
+    int argumentIndex;
+
+    @Option(displayName = "Parameter type",
+            description = "The type of the parameter that we add the argument for.",
+            example = "java.lang.String")
+    String parameterType;
+
+    @Option(displayName = "Parameter name",
+            description = "The name of the parameter that we add the argument for.",
+            required = false,
+            example = "name")
+    @Nullable String parameterName;
+
+    @Option(displayName = "Explicit cast",
+            description = "Explicitly cast the argument to the parameter type. Useful if the method is overridden with another type.",
+            required = false,
+            example = "true")
+    @Nullable Boolean explicitCast;
+
+    @Override
+    public String getInstanceNameSuffix() {
+        return String.format("%d in methods `%s`", argumentIndex, methodPattern);
+    }
+
+    @Override
+    public String getDisplayName() {
+        return "Add a `null` method argument";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Add a `null` argument to method invocations.";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return Preconditions.check(new UsesMethod<>(methodPattern), new AddNullMethodArgumentVisitor(new MethodMatcher(methodPattern)));
+    }
+
+    private class AddNullMethodArgumentVisitor extends JavaIsoVisitor<ExecutionContext> {
+        private final MethodMatcher methodMatcher;
+
+        public AddNullMethodArgumentVisitor(MethodMatcher methodMatcher) {
+            this.methodMatcher = methodMatcher;
+        }
+
+        @Override
+        public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, ExecutionContext ctx) {
+            J.MethodInvocation m = super.visitMethodInvocation(method, ctx);
+            return (J.MethodInvocation) visitMethodCall(m);
+        }
+
+        @Override
+        public J.NewClass visitNewClass(J.NewClass newClass, ExecutionContext ctx) {
+            J.NewClass n = super.visitNewClass(newClass, ctx);
+            return (J.NewClass) visitMethodCall(n);
+        }
+
+        private MethodCall visitMethodCall(MethodCall methodCall) {
+            MethodCall m = methodCall;
+            List<Expression> originalArgs = m.getArguments();
+            if (methodMatcher.matches(m) && (long) originalArgs.size() >= argumentIndex) {
+                List<Expression> args = new ArrayList<>(originalArgs);
+
+                if (args.size() == 1 && args.get(0) instanceof J.Empty) {
+                    args.remove(0);
+                }
+
+                Expression nullLiteral = new J.Literal(randomId(), args.isEmpty() ? Space.EMPTY : Space.SINGLE_SPACE, Markers.EMPTY, "null", "null", null, JavaType.Primitive.Null);
+                if (explicitCast == Boolean.TRUE) {
+                    nullLiteral = new J.TypeCast(randomId(), Space.SINGLE_SPACE, Markers.EMPTY,
+                            new J.ControlParentheses<>(randomId(), EMPTY, Markers.EMPTY,
+                                    new JRightPadded<>(TypeTree.build(parameterType), EMPTY, Markers.EMPTY)),
+                            nullLiteral);
+                }
+                m = m.withArguments(ListUtils.insert(args, nullLiteral, argumentIndex));
+
+                JavaType.Method methodType = m.getMethodType();
+                if (methodType != null) {
+                    m = m.withMethodType(methodType
+                            .withParameterNames(ListUtils.insert(methodType.getParameterNames(),
+                                    parameterName == null ? "arg" + argumentIndex : parameterName, argumentIndex))
+                            .withParameterTypes(ListUtils.insert(methodType.getParameterTypes(),
+                                    JavaType.buildType(parameterType), argumentIndex)));
+                    if (m instanceof J.MethodInvocation && ((J.MethodInvocation) m).getName().getType() != null) {
+                        m = ((J.MethodInvocation) m).withName(((J.MethodInvocation) m).getName().withType(m.getMethodType()));
+                    }
+                }
+            }
+            return m;
+        }
+
+    }
+}