SONARJAVA-6273 S3706: "stream" should not be used for Collection "forEach" calls (#5581)

Author: NoemieBenard

its/autoscan/src/test/resources/autoscan/diffs/diff_S3706.json

@@ -0,0 +1,6 @@
+{
+  "ruleKey": "S3706",
+  "hasTruePositives": true,
+  "falseNegatives": 0,
+  "falsePositives": 0
+}

its/ruling/src/test/resources/sonar-server/java-S3706.json

@@ -0,0 +1,12 @@
+{
+  "org.sonarsource.sonarqube:sonar-server:src/main/java/org/sonar/server/permission/ws/template/SearchTemplatesDataLoader.java": [
+    96
+  ],
+  "org.sonarsource.sonarqube:sonar-server:src/main/java/org/sonar/server/rule/ws/ShowAction.java": [
+    140
+  ],
+  "org.sonarsource.sonarqube:sonar-server:src/test/java/org/sonar/server/qualityprofile/RuleActivatorTest.java": [
+    863,
+    898
+  ]
+}

java-checks-test-sources/default/src/main/java/checks/StreamForeachCheck.java

@@ -0,0 +1,40 @@
+package checks;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Stream;
+
+public class StreamForeachCheck {
+
+  void unnecessaryStreamForEach(Collection<Integer> collection) {
+    collection.stream().forEach(System.out::println); // Noncompliant {{Simplify the code by replacing .stream().forEach() with .forEach().}}
+    //         ^^^^^^^^^^^^^^^^
+  }
+
+  void compliantCollectionForEach(Collection<Integer> collection) {
+    collection.forEach(System.out::println); // Compliant
+  }
+
+  void necessaryFilterForEach(Collection<String> col) {
+    col.stream().filter(s -> !s.isEmpty()).forEach(System.out::println);
+  }
+
+  void unnecessaryForEachOnSet(Set<String> set) {
+    set.stream().forEach(e -> System.out.println("Element: " + e)); // Noncompliant
+  }
+
+  void unnecessaryForEachOnList(List<String> list) {
+    list.stream().forEach(e -> System.out.println("Element: " + e)); // Noncompliant
+  }
+
+  void necessaryForEachOnParallelStream(Set<String> set) {
+    set.parallelStream().forEach(System.out::println); // Compliant
+  }
+
+  void sequentialStreamForEach(Collection<String> col) {
+    Stream<String> s = col.stream();
+    s.forEach(System.out::println); // Compliant (the rule ignores this case)
+  }
+
+}

java-checks/src/main/java/org/sonar/java/checks/StreamForeachCheck.java

@@ -0,0 +1,62 @@
+/*
+ * SonarQube Java
+ * Copyright (C) SonarSource Sàrl
+ * mailto:info AT sonarsource DOT com
+ *
+ * You can redistribute and/or modify this program under the terms of
+ * the Sonar Source-Available License Version 1, as published by SonarSource Sàrl.
+ *
+ * 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 Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+package org.sonar.java.checks;
+
+import java.util.List;
+import org.sonar.check.Rule;
+import org.sonar.plugins.java.api.IssuableSubscriptionVisitor;
+import org.sonar.plugins.java.api.semantic.MethodMatchers;
+import org.sonar.plugins.java.api.tree.MemberSelectExpressionTree;
+import org.sonar.plugins.java.api.tree.MethodInvocationTree;
+import org.sonar.plugins.java.api.tree.Tree;
+
+@Rule(key = "S3706")
+public class StreamForeachCheck extends IssuableSubscriptionVisitor {
+
+  private static final MethodMatchers STREAM_METHOD = MethodMatchers.create()
+    .ofSubTypes("java.util.Collection")
+    .names("stream")
+    .addWithoutParametersMatcher()
+    .build();
+
+  private static final MethodMatchers STREAM_FOREACH_METHOD = MethodMatchers.create()
+    .ofSubTypes("java.util.stream.Stream")
+    .names("forEach")
+    .withAnyParameters()
+    .build();
+
+  @Override
+  public List<Tree.Kind> nodesToVisit() {
+    return List.of(Tree.Kind.METHOD_INVOCATION);
+  }
+
+  @Override
+  public void visitNode(Tree tree) {
+    if (tree instanceof MethodInvocationTree mit && STREAM_FOREACH_METHOD.matches(mit)) {
+      checkUnnecessaryForEach(mit);
+    }
+  }
+
+  private void checkUnnecessaryForEach(MethodInvocationTree mitForEach) {
+    if (mitForEach.methodSelect() instanceof MemberSelectExpressionTree msetForEach
+      && msetForEach.expression() instanceof MethodInvocationTree mitStream
+      && STREAM_METHOD.matches(mitStream)
+      && mitStream.methodSelect() instanceof MemberSelectExpressionTree msetStream) {
+      reportIssue(msetStream.identifier(), msetForEach.identifier(), "Simplify the code by replacing .stream().forEach() with .forEach().");
+    }
+  }
+}

java-checks/src/test/java/org/sonar/java/checks/StreamForeachCheckTest.java

@@ -0,0 +1,43 @@
+/*
+ * SonarQube Java
+ * Copyright (C) SonarSource Sàrl
+ * mailto:info AT sonarsource DOT com
+ *
+ * You can redistribute and/or modify this program under the terms of
+ * the Sonar Source-Available License Version 1, as published by SonarSource Sàrl.
+ *
+ * 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 Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+package org.sonar.java.checks;
+
+import org.junit.jupiter.api.Test;
+import org.sonar.java.checks.verifier.CheckVerifier;
+
+import static org.sonar.java.checks.verifier.TestUtils.mainCodeSourcesPath;
+
+class StreamForeachCheckTest {
+  @Test
+  void test() {
+    StreamForeachCheck check = new StreamForeachCheck();
+    CheckVerifier.newVerifier()
+      .onFile(mainCodeSourcesPath("checks/StreamForeachCheck.java"))
+      .withCheck(check)
+      .verifyIssues();
+  }
+
+  @Test
+  void testWithoutSemantic() {
+    StreamForeachCheck check = new StreamForeachCheck();
+    CheckVerifier.newVerifier()
+      .onFile(mainCodeSourcesPath("checks/StreamForeachCheck.java"))
+      .withoutSemantic()
+      .withCheck(check)
+      .verifyIssues();
+  }
+}

sonar-java-plugin/src/main/resources/org/sonar/l10n/java/rules/java/S3706.html

@@ -0,0 +1,12 @@
+<h2>Why is this an issue?</h2>
+<p>There’s no need to invoke <code>stream()</code> on a <code>Collection</code> before a <code>forEach</code> call because each
+<code>Collection</code> has its own <code>forEach</code> method.</p>
+<h3>Noncompliant code example</h3>
+<pre>
+identifiers.stream().forEach(System.out::println);  // Noncompliant
+</pre>
+<h3>Compliant solution</h3>
+<pre>
+identifiers.forEach(System.out::println);  // Compliant
+</pre>
+

sonar-java-plugin/src/main/resources/org/sonar/l10n/java/rules/java/S3706.json

@@ -0,0 +1,15 @@
+{
+  "title": "\"stream\" should not be used for Collection \"forEach\" calls",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "2min"
+  },
+  "tags": [],
+  "defaultSeverity": "Minor",
+  "ruleSpecification": "RSPEC-3706",
+  "sqKey": "S3706",
+  "scope": "All",
+  "quickfix": "unknown"
+}

sonar-java-plugin/src/main/resources/org/sonar/l10n/java/rules/java/Sonar_agentic_AI_profile.json

@@ -259,6 +259,7 @@
     "S3599",
     "S3626",
     "S3631",
+    "S3706",
     "S3740",
     "S3751",
     "S3752",

sonar-java-plugin/src/main/resources/org/sonar/l10n/java/rules/java/Sonar_way_profile.json

@@ -276,6 +276,7 @@
     "S3599",
     "S3626",
     "S3631",
+    "S3706",
     "S3740",
     "S3751",
     "S3752",

sonar-java-plugin/src/test/java/org/sonar/plugins/java/JavaAgenticWayProfileTest.java

@@ -53,7 +53,7 @@ void profile_is_registered_as_expected() {
     BuiltInQualityProfilesDefinition.BuiltInQualityProfile actualProfile = profilesPerLanguages.get("java").get("Sonar agentic AI");
     assertThat(actualProfile.isDefault()).isFalse();
     assertThat(actualProfile.rules())
-      .hasSize(467)
+      .hasSize(468)
       .extracting(BuiltInQualityProfilesDefinition.BuiltInActiveRule::ruleKey)
       .doesNotContainAnyElementsOf(List.of(
         "S101",