SONAR-2018 Improve rule for detection of commented-out code

JSNI methods (GWT) should not be considered as commented-out code.

3 files changed, 31 insertions, 3 deletions

diff --git a/plugins/sonar-squid-java-plugin/src/main/java/org/sonar/java/ast/check/CommentedOutCodeLineCheck.java b/plugins/sonar-squid-java-plugin/src/main/java/org/sonar/java/ast/check/CommentedOutCodeLineCheck.java
index d4d42781297..da7e1160aa2 100644
--- a/plugins/sonar-squid-java-plugin/src/main/java/org/sonar/java/ast/check/CommentedOutCodeLineCheck.java
+++ b/plugins/sonar-squid-java-plugin/src/main/java/org/sonar/java/ast/check/CommentedOutCodeLineCheck.java
@@ -23,6 +23,7 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
 
+import org.apache.commons.lang.StringUtils;
 import org.sonar.check.Priority;
 import org.sonar.check.Rule;
 import org.sonar.java.ast.visitor.AstUtils;
@@ -78,9 +79,11 @@ public class CommentedOutCodeLineCheck extends JavaAstVisitor {
     }
 
     for (List<TextBlock> listOfComments : getFileContents().getCComments().values()) {
-      // This list contains not only comments in C style, but also Javadocs
+      // This list contains not only comments in C style, but also Javadocs and JSNI comments
       for (TextBlock comment : listOfComments) {
-        comments.add(comment);
+        if (!isJSNI(comment)) {
+          comments.add(comment);
+        }
       }
     }
   }
@@ -123,4 +126,18 @@ public class CommentedOutCodeLineCheck extends JavaAstVisitor {
     comments = null;
   }
 
+  private static final String START_JSNI = "/*-{";
+  private static final String END_JSNI = "}-*/";
+
+  /**
+   * From GWT documentation:
+   * A JSNI comment block begins with the exact token {@link #START_JSNI} and ends with the exact token {@link #END_JSNI}.
+   */
+  private boolean isJSNI(TextBlock comment) {
+    String[] lines = comment.getText();
+    String firstLine = lines[0];
+    String lastLine = lines[lines.length - 1];
+    return StringUtils.startsWith(firstLine, START_JSNI) && StringUtils.endsWith(lastLine, END_JSNI);
+  }
+
 }
diff --git a/plugins/sonar-squid-java-plugin/src/test/java/org/sonar/java/ast/check/CommentedOutCodeLineCheckTest.java b/plugins/sonar-squid-java-plugin/src/test/java/org/sonar/java/ast/check/CommentedOutCodeLineCheckTest.java
index b231567b3b8..2322b1bbdf5 100644
--- a/plugins/sonar-squid-java-plugin/src/test/java/org/sonar/java/ast/check/CommentedOutCodeLineCheckTest.java
+++ b/plugins/sonar-squid-java-plugin/src/test/java/org/sonar/java/ast/check/CommentedOutCodeLineCheckTest.java
@@ -49,7 +49,7 @@ public class CommentedOutCodeLineCheckTest {
   public void testDetection() {
     CheckMessages checkMessages = new CheckMessages((SourceFile) squid.search("CommentedCode.java"));
 
-    checkMessages.assertNext().atLine(26);
+    checkMessages.assertNext().atLine(26).withMessage("It's better to remove commented-out line of code.");
     checkMessages.assertNext().atLine(27);
     checkMessages.assertNext().atLine(28);
 
diff --git a/plugins/sonar-squid-java-plugin/test-resources/rules/CommentedCode.java b/plugins/sonar-squid-java-plugin/test-resources/rules/CommentedCode.java
index c7aa40ba06e..c2f0aef4955 100644
--- a/plugins/sonar-squid-java-plugin/test-resources/rules/CommentedCode.java
+++ b/plugins/sonar-squid-java-plugin/test-resources/rules/CommentedCode.java
@@ -49,6 +49,17 @@ public class CommentedCode {
   }
 
   /**
+   * From GWT documentation:
+   * JSNI methods are declared native and contain JavaScript code in a specially formatted comment block
+   * between the end of the parameter list and the trailing semicolon.
+   */
+  public static native void alert(String msg) /*-{
+    for (i=0;i<=5;i++) {
+      $wnd.alert(msg);
+    }
+  }-*/;
+
+  /**
    * No detection of commented-out code in Javadoc for method
    * for (Visitor visitor : visitors) {
    *   continue;