RenameLocalVariablesToCamelCase: Do not rename method argument names.

src/main/java/org/openrewrite/staticanalysis/RenameLocalVariablesToCamelCase.java

@@ -55,7 +55,7 @@ public String getDescription() {
         return "Reformat local variable and method parameter names to camelCase to comply with Java naming convention. " +
                 "The recipe will not rename variables declared in for loop controls or catches with a single character. " +
                 "The first character is set to lower case and existing capital letters are preserved. " +
-                "Special characters that are allowed in java field names `$` and `_` are removed. " +
+                "Special characters that are allowed in java field names `$` and `_` are removed (unless the name starts with one). " +
                 "If a special character is removed the next valid alphanumeric will be capitalized. " +
                 "Currently, does not support renaming members of classes. " +
                 "The recipe will not rename a variable if the result already exists in the class, conflicts with a java reserved keyword, or the result is blank.";
@@ -105,7 +105,7 @@ public J.VariableDeclarations visitVariableDeclarations(J.VariableDeclarations m
 
             private boolean isLocalVariable(J.VariableDeclarations mv) {
                 // The recipe will not rename variables declared in for loop controls or catches.
-                if (!isInMethodDeclarationBody() || isDeclaredInForLoopControl() || isDeclaredInCatch()) {
+                if (!isInMethodDeclarationBody() || isDeclaredInForLoopControl() || isDeclaredInCatch() || isMethodArgument()) {
                     return false;
                 }
 
@@ -119,6 +119,11 @@ private boolean isLocalVariable(J.VariableDeclarations mv) {
                 return true;
             }
 
+            private boolean isMethodArgument() {
+                return getCursor().getParentTreeCursor()
+                        .getValue() instanceof J.MethodDeclaration;
+            }
+
             private boolean isInMethodDeclarationBody() {
                 return getCursor().dropParentUntil(p -> p instanceof J.MethodDeclaration ||
                                                         p instanceof J.ClassDeclaration ||

src/test/java/org/openrewrite/staticanalysis/RenameLocalVariablesToCamelCaseTest.java

@@ -15,7 +15,9 @@
  */
 package org.openrewrite.staticanalysis;
 
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
+import org.junitpioneer.jupiter.ExpectedToFail;
 import org.openrewrite.DocumentExample;
 import org.openrewrite.Issue;
 import org.openrewrite.Recipe;
@@ -89,23 +91,23 @@ void renameLocalVariables() {
               class Test {
                   int DoNoTChange;
 
-                  public int addTen(int rename_one) {
+                  public int addTen(int dont_rename_one) {
                       double RenameTwo = 2.0;
                       float __rename__three__ = 2.0;
                       long _Rename__Four = 2.0;
-                      return rename_one + RenameTwo + __rename__three__ + _Rename__Four + 10;
+                      return dont_rename_one + RenameTwo + __rename__three__ + _Rename__Four + 10;
                   }
               }
               """,
             """
               class Test {
                   int DoNoTChange;
 
-                  public int addTen(int renameOne) {
+                  public int addTen(int dont_rename_one) {
                       double renameTwo = 2.0;
                       float renameThree = 2.0;
                       long renameFour = 2.0;
-                      return renameOne + renameTwo + renameThree + renameFour + 10;
+                      return dont_rename_one + renameTwo + renameThree + renameFour + 10;
                   }
               }
               """
@@ -114,6 +116,7 @@ public int addTen(int renameOne) {
     }
 
     @SuppressWarnings("JavadocDeclaration")
+    @Disabled
     @Issue("https://github.com/openrewrite/rewrite/issues/2437")
     @Test
     void renameJavaDocParam() {
@@ -438,6 +441,7 @@ void test() {
 
     @Test
     void renameFinalLocalVariables() {
+        //language=java
         rewriteRun(
           java(
             """
@@ -458,4 +462,21 @@ void test() {
         );
     }
 
+    @Issue("https://github.com/openrewrite/rewrite-static-analysis/pull/205")
+    @Test
+    void doNotRenameMethodArguments() {
+        //language=java
+        rewriteRun(
+          java(
+            """
+              class MyController {
+                  String getHello(String your_name) {
+                      return "hello " + your_name;
+                  }
+              }
+              """
+          )
+        );
+    }
+
 }