From 54efaf8cfebb1e64579c6a82509cfd4dfd134f87 Mon Sep 17 00:00:00 2001
From: Alban Auzeill <alban.auzeill@sonarsource.com>
Date: Fri, 10 Feb 2023 13:57:07 +0100
Subject: [PATCH] SONARJAVA-3995 FN S3400 should also report issues on static
 methods (#4308)

---
 .../main/java/checks/ConstantMethodCheck.java | 25 +++++++++++++++++++
 .../java/checks/ConstantMethodCheck.java      |  4 +--
 .../org/sonar/l10n/java/rules/java/S3400.html |  8 +++++-
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/java-checks-test-sources/src/main/java/checks/ConstantMethodCheck.java b/java-checks-test-sources/src/main/java/checks/ConstantMethodCheck.java
index a836c5f3fb7..36d32764322 100644
--- a/java-checks-test-sources/src/main/java/checks/ConstantMethodCheck.java
+++ b/java-checks-test-sources/src/main/java/checks/ConstantMethodCheck.java
@@ -66,6 +66,10 @@ final long finalMethod() {
       return 1L; // Noncompliant
     }
 
+    static long staticMethod() {
+      return 1L; // Noncompliant
+    }
+
     long noFinalMethod() {
       return 1L; // Compliant
     }
@@ -87,6 +91,27 @@ String noFinalMethod() {
     }
   }
 
+  enum MyEnum {
+    ONE() {
+      int overridableMethod() {
+        return 1; // Compliant, override
+      }
+    },
+    TWO(){
+      int overridableMethod() {
+        return 2; // Compliant, override
+      }
+    };
+
+    int overridableMethod() {
+      return 0; // Compliant, overridable
+    }
+
+    static int nonOverridableStaticMethod() {
+      return 0; // Noncompliant
+    }
+  }
+
   abstract class AbstractClass {
     abstract void abstractMethod(); // Compliant
 
diff --git a/java-checks/src/main/java/org/sonar/java/checks/ConstantMethodCheck.java b/java-checks/src/main/java/org/sonar/java/checks/ConstantMethodCheck.java
index 1b98213d01c..819175d7617 100644
--- a/java-checks/src/main/java/org/sonar/java/checks/ConstantMethodCheck.java
+++ b/java-checks/src/main/java/org/sonar/java/checks/ConstantMethodCheck.java
@@ -64,13 +64,13 @@ public void visitNode(Tree tree) {
 
   private static boolean isEffectivelyFinal(MethodTree methodTree) {
     Tree methodParent = methodTree.parent();
-    if (!(methodParent instanceof ClassTree) || methodParent.is(Tree.Kind.ANNOTATION_TYPE, Tree.Kind.INTERFACE, Kind.ENUM)) {
+    if (!(methodParent instanceof ClassTree) || methodParent.is(Tree.Kind.ANNOTATION_TYPE, Tree.Kind.INTERFACE)) {
       return false;
     } else if (methodParent.is(Tree.Kind.RECORD) || ((ClassTree)methodParent).symbol().isFinal()) {
       return true;
     }
     Symbol.MethodSymbol methodSymbol = methodTree.symbol();
-    return methodSymbol.isFinal() || methodSymbol.isPrivate();
+    return methodSymbol.isFinal() || methodSymbol.isPrivate() || methodSymbol.isStatic();
   }
 
   private static boolean isConstant(@Nullable ExpressionTree returnedExpression) {
diff --git a/java-checks/src/main/resources/org/sonar/l10n/java/rules/java/S3400.html b/java-checks/src/main/resources/org/sonar/l10n/java/rules/java/S3400.html
index aa100e38350..d85d1271f74 100644
--- a/java-checks/src/main/resources/org/sonar/l10n/java/rules/java/S3400.html
+++ b/java-checks/src/main/resources/org/sonar/l10n/java/rules/java/S3400.html
@@ -12,5 +12,11 @@ <h2>Compliant Solution</h2>
 static final int BEST_NUMBER = 12;
 </pre>
 <h2>Exceptions</h2>
-<p>Methods with annotations, such as <code>@Override</code> and Spring’s <code>@RequestMapping</code>, are ignored.</p>
+<p>The following types of method are ignored:</p>
+<ul>
+  <li> methods that override a method. </li>
+  <li> methods that are not final (not having the <code>final</code>, <code>private</code> or <code>static</code> modifier and not in a record or a
+  final class). </li>
+  <li> methods with annotations, such as <code>@Override</code> or Spring’s <code>@RequestMapping</code>. </li>
+</ul>