SONARJS-515 Rule: Results of operations on strings should not be ignored

its/ruling/src/test/expected/javascript-S1154.json

@@ -0,0 +1,8 @@
+{
+'project:dojo-1.8.1/dijit/dijit-all.js.uncompressed.js':[
+23138,
+],
+'project:dojo-1.8.1/dijit/form/ValidationTextBox.js.uncompressed.js':[
+285,
+],
+}

its/ruling/src/test/profile.xml

@@ -609,5 +609,10 @@
       <key>S3002</key>
       <priority>INFO</priority> <!-- Unary operators "+" and "-" should not be used with objects -->
     </rule>
+    <rule>
+      <repositoryKey>javascript</repositoryKey>  
+      <key>S1154</key>
+      <priority>INFO</priority><!-- Results of operations on strings should not be ignored -->
+    </rule>
   </rules>
 </profile>

javascript-checks/src/main/java/org/sonar/javascript/checks/CheckList.java

@@ -142,6 +142,7 @@ public static List<Class> getChecks() {
         NewOperatorMisuseCheck.class,
         WebSQLDatabaseCheck.class,
         PostMessageCheck.class,
+        UselessStringOperationCheck.class,
         LocalStorageCheck.class,
         UnaryPlusMinusWithObjectCheck.class,
         BackboneChangedIsUsedCheck.class,

javascript-checks/src/main/java/org/sonar/javascript/checks/UselessStringOperationCheck.java

@@ -0,0 +1,71 @@
+/*
+ * SonarQube JavaScript Plugin
+ * Copyright (C) 2011 SonarSource and Eriks Nukis
+ * [email protected]
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.javascript.checks;
+
+import com.google.common.collect.ImmutableList;
+import org.sonar.api.server.rule.RulesDefinition;
+import org.sonar.check.Priority;
+import org.sonar.check.Rule;
+import org.sonar.javascript.checks.utils.CheckUtils;
+import org.sonar.plugins.javascript.api.symbols.Type;
+import org.sonar.plugins.javascript.api.tree.Tree;
+import org.sonar.plugins.javascript.api.tree.Tree.Kind;
+import org.sonar.plugins.javascript.api.tree.expression.CallExpressionTree;
+import org.sonar.plugins.javascript.api.tree.expression.ExpressionTree;
+import org.sonar.plugins.javascript.api.tree.expression.MemberExpressionTree;
+import org.sonar.plugins.javascript.api.tree.statement.ExpressionStatementTree;
+import org.sonar.plugins.javascript.api.visitors.SubscriptionBaseTreeVisitor;
+import org.sonar.squidbridge.annotations.ActivatedByDefault;
+import org.sonar.squidbridge.annotations.SqaleConstantRemediation;
+import org.sonar.squidbridge.annotations.SqaleSubCharacteristic;
+
+import java.util.List;
+
+@Rule(
+  key = "S1154",
+  name = "Results of operations on strings should not be ignored",
+  priority = Priority.BLOCKER,
+  tags = {Tags.BUG})
+@ActivatedByDefault
+@SqaleSubCharacteristic(RulesDefinition.SubCharacteristics.INSTRUCTION_RELIABILITY)
+@SqaleConstantRemediation("20min")
+public class UselessStringOperationCheck extends SubscriptionBaseTreeVisitor {
+
+  @Override
+  public List<Kind> nodesToVisit() {
+    return ImmutableList.of(Kind.EXPRESSION_STATEMENT);
+  }
+
+  @Override
+  public void visitNode(Tree tree) {
+    Tree expression = ((ExpressionStatementTree) tree).expression();
+    if (expression.is(Kind.CALL_EXPRESSION)) {
+      ExpressionTree callee = ((CallExpressionTree) expression).callee();
+      if (callee.is(Kind.DOT_MEMBER_EXPRESSION)) {
+        MemberExpressionTree memberExpression = (MemberExpressionTree) callee;
+        if (memberExpression.object().types().containsOnly(Type.Kind.STRING)) {
+          String variableName = CheckUtils.asString(memberExpression.object());
+          addIssue(tree, variableName + " is an immutable object; you must either store or return the result of the operation.");
+        }
+      }
+    }
+  }
+
+}

javascript-checks/src/main/resources/org/sonar/l10n/javascript/rules/javascript/S1154.html

@@ -0,0 +1,14 @@
+<p>Doing an operation on a string without using the result of the operation is useless and is certainly due to a misunderstanding. </p>
+<h2>Noncompliant Code Example</h2>
+
+<pre>
+var str = "..."
+str.toUpperCase(); // Noncompliant
+</pre>
+<h2>Compliant Solution</h2>
+
+<pre>
+var str = "..."
+str = str.toUpperCase();
+</pre>
+

javascript-checks/src/test/java/org/sonar/javascript/checks/UselessStringOperationCheckTest.java

@@ -0,0 +1,38 @@
+/*
+ * SonarQube JavaScript Plugin
+ * Copyright (C) 2011 SonarSource and Eriks Nukis
+ * [email protected]
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
+ */
+package org.sonar.javascript.checks;
+
+import org.junit.Test;
+import org.sonar.plugins.javascript.api.tests.TreeCheckTest;
+import org.sonar.squidbridge.checks.CheckMessagesVerifier;
+
+public class UselessStringOperationCheckTest extends TreeCheckTest {
+
+  @Test
+  public void test() {
+    UselessStringOperationCheck check = new UselessStringOperationCheck();
+    CheckMessagesVerifier.verify(getIssues("src/test/resources/checks/UselessStringOperation.js", check))
+      .next().atLine(4).withMessage("str is an immutable object; you must either store or return the result of the operation.")
+      .next().atLine(5).withMessage("\"abc\" is an immutable object; you must either store or return the result of the operation.")
+      .next().atLine(6)
+      .noMore();
+  }
+
+}

javascript-checks/src/test/resources/checks/UselessStringOperation.js

@@ -0,0 +1,10 @@
+var var1 = "abc".toUpperCase(); // OK
+unknown.toUpperCase(); // OK
+var str = "abcd"; 
+str.toUpperCase(); // NOK
+"abc".toUpperCase(); // NOK
+str.substring(1,2); // NOK
+
+var x = "abc";
+x = something();
+x.toUpperCase(); // OK

sonar-javascript-plugin/src/test/java/org/sonar/plugins/javascript/JavaScriptProfileTest.java

@@ -46,7 +46,7 @@ public void should_create_sonar_way_profile() {
     assertThat(profile.getLanguage()).isEqualTo(JavaScriptLanguage.KEY);
     assertThat(profile.getName()).isEqualTo(CheckList.SONAR_WAY_PROFILE);
     assertThat(profile.getActiveRulesByRepository(CheckList.REPOSITORY_KEY))
-        .hasSize(77);
+        .hasSize(78);
     assertThat(validation.hasErrors()).isFalse();
   }