Add Rule EC82: Make variable constant

Author: Hachemi ATROUNE

CHANGELOG.md

@@ -13,6 +13,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Deleted
 
+
+## [1.6.2] - 2024-05-30
+
+### Added
+
+- EC82 rule : A variable is never reassigned and can be made constant
+
 ## [1.6.1] - 2024-05-15
 
 ### Changed

src/main/java/fr/greencodeinitiative/java/JavaCheckRegistrar.java

@@ -20,21 +20,7 @@
 import java.util.Collections;
 import java.util.List;
 
-import fr.greencodeinitiative.java.checks.ArrayCopyCheck;
-import fr.greencodeinitiative.java.checks.AvoidFullSQLRequest;
-import fr.greencodeinitiative.java.checks.AvoidGettingSizeCollectionInLoop;
-import fr.greencodeinitiative.java.checks.AvoidMultipleIfElseStatement;
-import fr.greencodeinitiative.java.checks.AvoidRegexPatternNotStatic;
-import fr.greencodeinitiative.java.checks.AvoidSQLRequestInLoop;
-import fr.greencodeinitiative.java.checks.AvoidSetConstantInBatchUpdate;
-import fr.greencodeinitiative.java.checks.AvoidSpringRepositoryCallInLoopOrStreamCheck;
-import fr.greencodeinitiative.java.checks.AvoidStatementForDMLQueries;
-import fr.greencodeinitiative.java.checks.AvoidUsageOfStaticCollections;
-import fr.greencodeinitiative.java.checks.FreeResourcesOfAutoCloseableInterface;
-import fr.greencodeinitiative.java.checks.IncrementCheck;
-import fr.greencodeinitiative.java.checks.InitializeBufferWithAppropriateSize;
-import fr.greencodeinitiative.java.checks.NoFunctionCallWhenDeclaringForLoop;
-import fr.greencodeinitiative.java.checks.OptimizeReadFileExceptions;
+import fr.greencodeinitiative.java.checks.*;
 import org.sonar.plugins.java.api.CheckRegistrar;
 import org.sonar.plugins.java.api.JavaCheck;
 import org.sonarsource.api.sonarlint.SonarLintSide;
@@ -62,7 +48,8 @@ public class JavaCheckRegistrar implements CheckRegistrar {
             InitializeBufferWithAppropriateSize.class,
             AvoidSetConstantInBatchUpdate.class,
             FreeResourcesOfAutoCloseableInterface.class,
-            AvoidMultipleIfElseStatement.class
+            AvoidMultipleIfElseStatement.class,
+            MakeVariableConstant.class
     );
 
     /**

src/main/java/fr/greencodeinitiative/java/checks/MakeVariableConstant.java

@@ -0,0 +1,80 @@
+/*
+ * ecoCode - Java language - Provides rules to reduce the environmental footprint of your Java programs
+ * Copyright © 2023 Green Code Initiative (https://www.ecocode.io)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package fr.greencodeinitiative.java.checks;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.sonar.check.Rule;
+import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
+import org.sonar.plugins.java.api.semantic.Symbol;
+import org.sonar.plugins.java.api.tree.*;
+import org.sonarsource.analyzer.commons.annotations.DeprecatedRuleKey;
+
+@Rule(key = "EC82")
+@DeprecatedRuleKey(repositoryKey = "greencodeinitiative-java", ruleKey = "S82")
+public class MakeVariableConstant extends IssuableSubscriptionVisitor {
+    public static final String ERROR_MESSAGE = "A variable is never reassigned and can be made constant";
+
+    @Override
+    public List<Tree.Kind> nodesToVisit() {
+        return List.of(Tree.Kind.VARIABLE);
+    }
+
+    @Override
+    public void visitNode(Tree tree) {
+        VariableTree variableTree = (VariableTree) tree;
+        Symbol symbol = variableTree.symbol();
+        if (symbol.isVariableSymbol() && !symbol.isFinal()) {
+            boolean reassigned = isReassigned(symbol);
+            if (!reassigned) {
+                reportIssue(variableTree.simpleName(), ERROR_MESSAGE);
+            }
+        }
+    }
+
+    private boolean isReassigned(Symbol symbol) {
+        Tree parent = symbol.declaration().parent();
+        if (parent instanceof BlockTree) {
+            return isReassignedInBlock(symbol, (BlockTree) parent);
+        }
+        return false;
+    }
+
+    private boolean isReassignedInBlock(Symbol symbol, BlockTree blockTree) {
+        List<AssignmentExpressionTree> assignments = new ArrayList<>();
+        List<StatementTree> body = blockTree.body();
+
+        for (StatementTree statement : body) {
+            if (statement.is(Tree.Kind.EXPRESSION_STATEMENT)) {
+                ExpressionTree expression = ((ExpressionStatementTree) statement).expression();
+                if (expression.is(Tree.Kind.ASSIGNMENT)) {
+                    assignments.add((AssignmentExpressionTree) expression);
+                }
+            }
+        }
+
+        for (AssignmentExpressionTree assignment : assignments) {
+            if (((IdentifierTree) assignment.variable()).symbol().equals(symbol)) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

src/test/files/MakeVariableConstantTest.java

@@ -0,0 +1,7 @@
+public class MakeVariableConstantTest {
+
+    public void testEc82() {
+        String test = "test"; // Noncompliant {{A variable is never reassigned and can be made constant}}
+        System.out.println("Hello World");
+    }
+}

src/test/java/fr/greencodeinitiative/java/JavaCheckRegistrarTest.java

@@ -31,7 +31,7 @@ void checkNumberRules() {
         final JavaCheckRegistrar registrar = new JavaCheckRegistrar();
         registrar.register(context);
 
-        assertThat(context.checkClasses()).hasSize(15);
+        assertThat(context.checkClasses()).hasSize(16);
         assertThat(context.testCheckClasses()).isEmpty();
 
     }

src/test/java/fr/greencodeinitiative/java/JavaRulesDefinitionTest.java

@@ -46,7 +46,7 @@ void init() {
         RulesDefinition.Context context = new RulesDefinition.Context();
         rulesDefinition.define(context);
         repository = context.repository(rulesDefinition.repositoryKey());
-        rulesSize = 15;
+        rulesSize = 16;
     }
 
     @Test

src/test/java/fr/greencodeinitiative/java/checks/MakeVariableConstantTest.java

@@ -0,0 +1,17 @@
+package fr.greencodeinitiative.java.checks;
+
+import org.junit.jupiter.api.Test;
+import org.sonar.java.checks.verifier.CheckVerifier;
+
+public class MakeVariableConstantTest {
+
+    @Test
+    void test() {
+        CheckVerifier.newVerifier()
+                .onFile("src/test/files/MakeVariableConstantTest.java")
+                .withCheck(new MakeVariableConstant())
+                .verifyIssues();
+    }
+}
+
+