Correctly evaluate nullable Boolean

Author: timtebeek

src/main/java/org/openrewrite/java/migrate/guava/AbstractNoGuavaImmutableOf.java

@@ -42,14 +42,15 @@ abstract class AbstractNoGuavaImmutableOf extends Recipe {
                           "The default value is false.",
             example = "true",
             required = false)
+    @Nullable
     Boolean convertReturnType;
 
     AbstractNoGuavaImmutableOf(String guavaType, String javaType) {
         this.guavaType = guavaType;
         this.javaType = javaType;
     }
 
-    AbstractNoGuavaImmutableOf(String guavaType, String javaType, boolean convertReturnType) {
+    AbstractNoGuavaImmutableOf(String guavaType, String javaType, @Nullable Boolean convertReturnType) {
         this.guavaType = guavaType;
         this.javaType = javaType;
         this.convertReturnType = convertReturnType;
@@ -116,10 +117,9 @@ public J visitMethodInvocation(J.MethodInvocation method, ExecutionContext ctx)
             @Override
             public J.VariableDeclarations visitVariableDeclarations(J.VariableDeclarations multiVariable, ExecutionContext ctx) {
                 J.VariableDeclarations mv = (J.VariableDeclarations) super.visitVariableDeclarations(multiVariable, ctx);
-                if (!convertReturnType) {
-                    return mv;
-                }
-                if (multiVariable != mv && TypeUtils.isOfClassType(mv.getType(), guavaType)) {
+                if (Boolean.TRUE.equals(convertReturnType) &&
+                    multiVariable != mv &&
+                    TypeUtils.isOfClassType(mv.getType(), guavaType)) {
                     JavaType newType = JavaType.buildType(javaType);
                     mv = mv.withTypeExpression(mv.getTypeExpression() == null ?
                             null : createNewTypeExpression(mv.getTypeExpression(), newType));
@@ -132,7 +132,6 @@ public J.VariableDeclarations visitVariableDeclarations(J.VariableDeclarations m
                         return variable;
                     }));
                 }
-
                 return mv;
             }
 
@@ -223,7 +222,7 @@ private boolean isParentTypeDownCast(MethodCall immutableMethod) {
             private boolean isParentTypeMatched(@Nullable JavaType type) {
                 JavaType.FullyQualified fq = TypeUtils.asFullyQualified(type);
                 return TypeUtils.isOfClassType(fq, javaType) ||
-                       (convertReturnType && TypeUtils.isOfClassType(fq, guavaType)) ||
+                       (Boolean.TRUE.equals(convertReturnType) && TypeUtils.isOfClassType(fq, guavaType)) ||
                        TypeUtils.isOfClassType(fq, "java.lang.Object");
             }
         });

src/main/java/org/openrewrite/java/migrate/guava/NoGuavaImmutableListOf.java

@@ -15,12 +15,14 @@
  */
 package org.openrewrite.java.migrate.guava;
 
+import org.jspecify.annotations.Nullable;
+
 public class NoGuavaImmutableListOf extends AbstractNoGuavaImmutableOf {
     public NoGuavaImmutableListOf() {
         super("com.google.common.collect.ImmutableList", "java.util.List");
     }
 
-    public NoGuavaImmutableListOf(boolean convertReturnType) {
+    public NoGuavaImmutableListOf(@Nullable Boolean convertReturnType) {
         super("com.google.common.collect.ImmutableList", "java.util.List", convertReturnType);
     }
 }

src/main/java/org/openrewrite/java/migrate/guava/NoGuavaImmutableMapOf.java

@@ -15,12 +15,14 @@
  */
 package org.openrewrite.java.migrate.guava;
 
+import org.jspecify.annotations.Nullable;
+
 public class NoGuavaImmutableMapOf extends AbstractNoGuavaImmutableOf {
     public NoGuavaImmutableMapOf() {
         super("com.google.common.collect.ImmutableMap", "java.util.Map");
     }
 
-    public NoGuavaImmutableMapOf(boolean convertReturnType) {
+    public NoGuavaImmutableMapOf(@Nullable Boolean convertReturnType) {
         super("com.google.common.collect.ImmutableMap", "java.util.Map", convertReturnType);
     }
 }

src/main/java/org/openrewrite/java/migrate/guava/NoGuavaImmutableSetOf.java

@@ -15,12 +15,14 @@
  */
 package org.openrewrite.java.migrate.guava;
 
+import org.jspecify.annotations.Nullable;
+
 public class NoGuavaImmutableSetOf extends AbstractNoGuavaImmutableOf {
     public NoGuavaImmutableSetOf() {
         super("com.google.common.collect.ImmutableSet", "java.util.Set");
     }
 
-    public NoGuavaImmutableSetOf(boolean convertReturnType) {
+    public NoGuavaImmutableSetOf(@Nullable Boolean convertReturnType) {
         super("com.google.common.collect.ImmutableSet", "java.util.Set", convertReturnType);
     }
 }