From a208e569d4b24af6e542a821aafec23da1e3c63d Mon Sep 17 00:00:00 2001
From: Bas Leijdekkers <basleijdekkers@gmail.com>
Date: Thu, 9 Feb 2023 17:44:31 +0100
Subject: [PATCH] Java: recognize readObjectNoData() as a serialization method
 (IDEA-286800)

for "Unused declaration" inspection

GitOrigin-RevId: 5b5c262ea38dceefde5eb565b9c01225d4bfb8ba
---
 .../UnusedDeclarationInspectionBase.java      | 26 ++++++++++++++-----
 .../deadCode/serializable/src/Test.java       |  1 +
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java b/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java
index d218f9798625..2dab07da825e 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionBase.java
@@ -179,7 +179,7 @@ public class UnusedDeclarationInspectionBase extends GlobalInspectionTool {
     if (!equalsToText(parameters.get(0).getType(), "java.io.ObjectOutputStream")) return false;
     if (method.isStatic()) return false;
     UClass aClass = UDeclarationKt.getContainingDeclaration(method, UClass.class);
-    return !(aClass != null && !isSerializable(aClass, refClass));
+    return aClass == null || isSerializable(aClass, refClass);
   }
 
   private static boolean isReadObjectMethod(@NotNull UMethod method, @Nullable RefClass refClass) {
@@ -190,7 +190,17 @@ public class UnusedDeclarationInspectionBase extends GlobalInspectionTool {
     if (!equalsToText(parameters.get(0).getType(), "java.io.ObjectInputStream")) return false;
     if (method.isStatic()) return false;
     UClass aClass = UDeclarationKt.getContainingDeclaration(method, UClass.class);
-    return !(aClass != null && !isSerializable(aClass, refClass));
+    return aClass == null || isSerializable(aClass, refClass);
+  }
+
+  private static boolean isReadObjectNoDataMethod(@NotNull UMethod method, @Nullable RefClass refClass) {
+    String name = method.getName();
+    if (!"readObjectNoData".equals(name)) return false;
+    if (!method.getUastParameters().isEmpty()) return false;
+    if (!equalsToText(method.getReturnType(), PsiKeyword.VOID)) return false;
+    if (method.isStatic()) return false;
+    UClass aClass = UDeclarationKt.getContainingDeclaration(method, UClass.class);
+    return aClass == null || isSerializable(aClass, refClass);
   }
 
   private static boolean isWriteReplaceMethod(@NotNull UMethod method, @Nullable RefClass refClass) {
@@ -201,7 +211,7 @@ public class UnusedDeclarationInspectionBase extends GlobalInspectionTool {
     if (!equalsToText(method.getReturnType(), CommonClassNames.JAVA_LANG_OBJECT)) return false;
     if (method.isStatic()) return false;
     UClass aClass = UDeclarationKt.getContainingDeclaration(method, UClass.class);
-    return !(aClass != null && !isSerializable(aClass, refClass));
+    return aClass == null || isSerializable(aClass, refClass);
   }
 
   private static boolean isReadResolveMethod(@NotNull UMethod method, @Nullable RefClass refClass) {
@@ -212,7 +222,7 @@ public class UnusedDeclarationInspectionBase extends GlobalInspectionTool {
     if (!equalsToText(method.getReturnType(), CommonClassNames.JAVA_LANG_OBJECT)) return false;
     if (method.isStatic()) return false;
     final UClass aClass = UDeclarationKt.getContainingDeclaration(method, UClass.class);
-    return !(aClass != null && !isSerializable(aClass, refClass));
+    return aClass == null || isSerializable(aClass, refClass);
   }
 
   private static boolean equalsToText(PsiType type, String text) {
@@ -509,8 +519,12 @@ public class UnusedDeclarationInspectionBase extends GlobalInspectionTool {
   }
 
   private static boolean isSerializablePatternMethod(@NotNull UMethod psiMethod, @Nullable RefClass refClass) {
-    return isReadObjectMethod(psiMethod, refClass) || isWriteObjectMethod(psiMethod, refClass) || isReadResolveMethod(psiMethod, refClass) ||
-           isWriteReplaceMethod(psiMethod, refClass) || isExternalizableNoParameterConstructor(psiMethod, refClass);
+    return isReadObjectMethod(psiMethod, refClass) ||
+           isReadObjectNoDataMethod(psiMethod, refClass) ||
+           isWriteObjectMethod(psiMethod, refClass) ||
+           isReadResolveMethod(psiMethod, refClass) ||
+           isWriteReplaceMethod(psiMethod, refClass) ||
+           isExternalizableNoParameterConstructor(psiMethod, refClass);
   }
 
   private static boolean belongsToRepeatableAnnotationContainer(@NotNull UMethod uMethod, @Nullable RefClass ownerRefClass) {
diff --git a/java/java-tests/testData/inspection/deadCode/serializable/src/Test.java b/java/java-tests/testData/inspection/deadCode/serializable/src/Test.java
index 5afb0ecb21d5..5e9080c4ee6b 100644
--- a/java/java-tests/testData/inspection/deadCode/serializable/src/Test.java
+++ b/java/java-tests/testData/inspection/deadCode/serializable/src/Test.java
@@ -3,4 +3,5 @@ public class Test implements java.io.Serializable {
   private void readObject(java.io.ObjectInputStream in) {}
   public Object writeReplace() { return null; }
   public Object readResolve() { return null; }
+  public void readObjectNoData() {}
 }
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