From 7ed7fc0e42a5e51089ea76b4b0ad08af8827334a Mon Sep 17 00:00:00 2001
From: Andreas Dangel <andreas.dangel@pmd-code.org>
Date: Fri, 27 May 2022 15:04:36 +0200
Subject: [PATCH] [java] EmptyControlStatement: Fix NPE for concise
 try-with-resources

---
 .../sourceforge/pmd/lang/java/ast/ASTResource.java |  9 +++++++++
 .../rule/codestyle/EmptyControlStatementRule.java  |  2 +-
 .../rule/codestyle/xml/EmptyControlStatement.xml   | 14 ++++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTResource.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTResource.java
index f6ce7781cb..b9aafd7f83 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTResource.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTResource.java
@@ -25,6 +25,15 @@ public class ASTResource extends ASTFormalParameter {
         return visitor.visit(this, data);
     }
 
+    public String getName() {
+        ASTVariableDeclaratorId variableDeclaratorId = getVariableDeclaratorId();
+        if (variableDeclaratorId != null) {
+            return variableDeclaratorId.getName();
+        }
+        // concise try-with-resources
+        return getFirstChildOfType(ASTName.class).getImage();
+    }
+
     // TODO Should we deprecate all methods from ASTFormalParameter?
 
 }
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/codestyle/EmptyControlStatementRule.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/codestyle/EmptyControlStatementRule.java
index 5de4bca7ed..c9b075f067 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/codestyle/EmptyControlStatementRule.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/codestyle/EmptyControlStatementRule.java
@@ -132,7 +132,7 @@ public class EmptyControlStatementRule extends AbstractJavaRule {
             if (resources != null) {
                 for (ASTResource resource : resources.findDescendantsOfType(ASTResource.class)) {
                     hasResource = true;
-                    String name = resource.getVariableDeclaratorId().getName();
+                    String name = resource.getName();
                     if (!JavaRuleUtil.isExplicitUnusedVarName(name)) {
                         allResourcesIgnored = false;
                         break;
diff --git a/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/codestyle/xml/EmptyControlStatement.xml b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/codestyle/xml/EmptyControlStatement.xml
index 69275f3bc9..1ccd313fff 100644
--- a/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/codestyle/xml/EmptyControlStatement.xml
+++ b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/codestyle/xml/EmptyControlStatement.xml
@@ -106,6 +106,20 @@
             ]]></code>
     </test-code>
 
+    <test-code>
+        <description>empty concise try-with-resource - not ok</description>
+        <expected-problems>1</expected-problems>
+        <expected-linenumbers>4</expected-linenumbers>
+        <code><![CDATA[
+            import java.io.InputStream;
+            class X {
+                void method(InputStream in) {
+                    try (in) {
+                    }
+                }
+            }
+            ]]></code>
+    </test-code>
 
     <test-code>
         <description>pos, empty synchronized stmt</description>