SONARJAVA-6121 : Fix FP for rule S2694 raising on compact source files (#5465)

Co-authored-by: Tomasz Tylenda <tomasz.tylenda@sonarsource.com>

Author: rombirli

…hecks/InnerStaticClassesCheckSample.java …Check/InnerStaticClassesCheckSample.javajava-checks/src/test/files/checks/InnerStaticClassesCheckSample.java renamed to java-checks-test-sources/default/src/main/java/checks/InnerStaticClassesCheck/InnerStaticClassesCheckSample.java java-checks/src/test/files/checks/InnerStaticClassesCheckSample.java renamed to java-checks-test-sources/default/src/main/java/checks/InnerStaticClassesCheck/InnerStaticClassesCheckSample.java

@@ -1,4 +1,4 @@
-package foo;
+package checks.InnerStaticClassesCheck;
 
 class Fruit {
   private int value;
@@ -113,7 +113,7 @@ class A {
 
   class B { // Compliant inner class refers to field.
     Bar foo() {
-      return new String() {
+      return new Bar() {
         public String toString() { return ""+fielda;}
       };
     }
@@ -125,14 +125,14 @@ Object foo() {
   }
 
   class SubB extends B {  // Compliant since super class is not static
-    Object foo() {
-      return new Object();
+    Bar foo() {
+      return new Bar();
     }
   }
 
   class SubSubB extends SubB {  // Compliant since super class is not static
-    Object foo() {
-      return new Object();
+    Bar foo() {
+      return new Bar();
     }
   }
 
@@ -146,19 +146,19 @@ class InnerArrayList extends java.util.ArrayList<String> { // Noncompliant
 
 }
 
-public class Extendable {
+class Extendable {
   protected int field;
 }
 
-public class Foo extends Extendable {
+class Foo extends Extendable {
 
   class Inner { // Compliant field is refered.
     void plop(){
       System.out.println(field);
     }
   }
 }
-public class A1 {
+class A1 {
   private int field;
 
   class B { // Noncompliant
@@ -177,7 +177,7 @@ public String toString() {
   void usedInAnonymousClass() {
     final String myString = "";
     method(new toImplement() { // Compliant my String is used.
-      void fun(String s) {
+      public void fun(String s) {
         myString.length();
       }
     });
@@ -200,10 +200,10 @@ public Inner() {
     }
   }
 }
-public class A4 {
+class A4 {
   public void m(int a) {
     class B { // compliant cannot be made static
-      void foo() {
+      int foo() {
         return a;
       }
     }

java-checks-test-sources/default/src/main/java/checks/InnerStaticClassesCheck/InnerStaticClassesCompactSourceFileSample.java

@@ -0,0 +1,11 @@
+
+void main() { // just to make the file is a compact source file
+}
+
+class A { // Compliant, FP raised here
+}
+
+class C {
+  class D { // Noncompliant
+  }
+}

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

@@ -49,6 +49,10 @@ public void scanFile(final JavaFileScannerContext context) {
 
   @Override
   public void visitClass(ClassTree tree) {
+    if (tree.is(Tree.Kind.IMPLICIT_CLASS)) {
+      // this rule doesn't apply to implicit classes (compact source files)
+      return;
+    }
     Symbol.TypeSymbol symbol = tree.symbol();
     outerClasses.push(symbol);
     atLeastOneReference.push(Boolean.FALSE);

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

@@ -19,14 +19,23 @@
 import org.junit.jupiter.api.Test;
 import org.sonar.java.checks.verifier.CheckVerifier;
 
+import static org.sonar.java.checks.verifier.TestUtils.mainCodeSourcesPath;
+
 class InnerStaticClassesCheckTest {
 
   @Test
   void test() {
     CheckVerifier.newVerifier()
-      .onFile("src/test/files/checks/InnerStaticClassesCheckSample.java")
+      .onFile(mainCodeSourcesPath("checks/InnerStaticClassesCheck/InnerStaticClassesCheckSample.java"))
       .withCheck(new InnerStaticClassesCheck())
       .verifyIssues();
   }
 
+  @Test
+  void testCompactSourceFiles() {
+    CheckVerifier.newVerifier()
+      .onFile(mainCodeSourcesPath("checks/InnerStaticClassesCheck/InnerStaticClassesCompactSourceFileSample.java"))
+      .withCheck(new InnerStaticClassesCheck())
+      .verifyNoIssues();
+  }
 }