From 0c91f2472cb187192e6b5f7bf77570999190d51c Mon Sep 17 00:00:00 2001
From: "Kukzze ." <dakshrawat320@gmail.com>
Date: Wed, 28 Oct 2026 10:37:30 +0530
Subject: [PATCH] Fix RedundantNullabilityCheck for nested types

---
 .../checks/RedundantNullabilityCheck.java     | 14 ++++++--
 .../checks/TestRedundantNullabilityCheck.java | 17 +++++++++
 .../java/testdata/RedundantNullability.java   | 36 +++++++++++++++++++
 3 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 paper-checkstyle/src/test/java/io/papermc/checkstyle/checks/TestRedundantNullabilityCheck.java
 create mode 100644 paper-checkstyle/src/testData/java/testdata/RedundantNullability.java

diff --git a/paper-checkstyle/src/main/java/io/papermc/checkstyle/checks/RedundantNullabilityCheck.java b/paper-checkstyle/src/main/java/io/papermc/checkstyle/checks/RedundantNullabilityCheck.java
index 1ed6c695519a..40db9c36e36b 100644
--- a/paper-checkstyle/src/main/java/io/papermc/checkstyle/checks/RedundantNullabilityCheck.java
+++ b/paper-checkstyle/src/main/java/io/papermc/checkstyle/checks/RedundantNullabilityCheck.java
@@ -31,10 +31,20 @@ public int[] getRequiredTokens() {
 
     @Override
     public void visitToken(final DetailAST ast) {
-        final boolean pkgIsNullMarked = Util.isPackageInfoAnnotated(Path.of(this.getFilePath()), NullabilityAnnotationsCheck::isNullMarkedAnnotation);
         final DetailAST nullMarkedAnnotation = NullabilityAnnotationsCheck.getNullMarkedAnnotation(ast);
-        if (pkgIsNullMarked && nullMarkedAnnotation != null) {
+        if (nullMarkedAnnotation == null) {
+            return;
+        }
+        final boolean pkgIsNullMarked = Util.isPackageInfoAnnotated(Path.of(this.getFilePath()), NullabilityAnnotationsCheck::isNullMarkedAnnotation);
+        if (pkgIsNullMarked) {
             this.log(nullMarkedAnnotation.getLineNo(), ast.getColumnNo() - 1, "Redundant NullMarked annotation");
+            return;
+        }
+        for (DetailAST parentDef = Util.getEnclosingTypeDeclaration(ast); parentDef != null; parentDef = Util.getEnclosingTypeDeclaration(parentDef)) {
+            if (NullabilityAnnotationsCheck.getNullMarkedAnnotation(parentDef) != null) {
+                this.log(nullMarkedAnnotation.getLineNo(), ast.getColumnNo() - 1, "Redundant NullMarked annotation");
+                return;
+            }
         }
     }
 }
diff --git a/paper-checkstyle/src/test/java/io/papermc/checkstyle/checks/TestRedundantNullabilityCheck.java b/paper-checkstyle/src/test/java/io/papermc/checkstyle/checks/TestRedundantNullabilityCheck.java
new file mode 100644
index 000000000000..e175bf96ac23
--- /dev/null
+++ b/paper-checkstyle/src/test/java/io/papermc/checkstyle/checks/TestRedundantNullabilityCheck.java
@@ -0,0 +1,17 @@
+package io.papermc.checkstyle.checks;
+
+import io.papermc.checkstyle.CheckTest;
+import io.papermc.checkstyle.CheckTestBuilder;
+
+class TestRedundantNullabilityCheck {
+
+    @CheckTest("testdata.RedundantNullability")
+    void test(final CheckTestBuilder builder) {
+        builder
+            .addViolation("10:8: Redundant NullMarked annotation")
+            .addViolation("14:8: Redundant NullMarked annotation")
+            .addViolation("18:8: Redundant NullMarked annotation")
+            .addViolation("22:8: Redundant NullMarked annotation")
+            .addCheck(new RedundantNullabilityCheck());
+    }
+}
diff --git a/paper-checkstyle/src/testData/java/testdata/RedundantNullability.java b/paper-checkstyle/src/testData/java/testdata/RedundantNullability.java
new file mode 100644
index 000000000000..0598bda5aa81
--- /dev/null
+++ b/paper-checkstyle/src/testData/java/testdata/RedundantNullability.java
@@ -0,0 +1,36 @@
+package testdata;
+
+import org.jspecify.annotations.NullMarked;
+
+public class RedundantNullability {
+
+    @NullMarked
+    public static class OuterClass {
+
+        @NullMarked
+        public static class RedundantInnerClass {
+        }
+
+        @NullMarked
+        public interface RedundantInnerInterface {
+        }
+
+        @NullMarked
+        public record RedundantInnerRecord() {
+        }
+
+        @NullMarked
+        public enum RedundantInnerEnum {
+        }
+
+        public static class ValidInnerClass {
+        }
+    }
+
+    public static class NonAnnotatedOuter {
+
+        @NullMarked
+        public static class ValidAnnotatedInner {
+        }
+    }
+}