From 81a72cb43ef77f920732a4db80a7885e129e6a67 Mon Sep 17 00:00:00 2001
From: Andreas Dangel <andreas.dangel@pmd-code.org>
Date: Thu, 17 Sep 2020 18:49:21 +0200
Subject: [PATCH] [java] CloseResource: Fix NPE in case of "var"

---
 docs/pages/release_notes.md                   |  1 +
 .../rule/errorprone/CloseResourceRule.java    |  4 ++--
 .../rule/errorprone/xml/CloseResource.xml     | 21 +++++++++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/docs/pages/release_notes.md b/docs/pages/release_notes.md
index 2fa8a74515..3c1423c57f 100644
--- a/docs/pages/release_notes.md
+++ b/docs/pages/release_notes.md
@@ -32,6 +32,7 @@ AbstractTokenizer and the custom tokenizers of Fortran, Perl and Ruby are deprec
 * pmd-java
     * [#2708](https://github.com/pmd/pmd/issues/2708): \[java] False positive FinalFieldCouldBeStatic when using lombok Builder.Default
     * [#2738](https://github.com/pmd/pmd/issues/2738): \[java] Custom rule with @ExhaustiveEnumSwitch throws NPE
+    * [#2755](https://github.com/pmd/pmd/issues/2755): \[java] \[6.27.0] Exception applying rule CloseResource on file ... java.lang.NullPointerException
     * [#2756](https://github.com/pmd/pmd/issues/2756): \[java] TypeTestUtil fails with NPE for anonymous class
     * [#2759](https://github.com/pmd/pmd/issues/2759): \[java] False positive in UnusedAssignment
     * [#2767](https://github.com/pmd/pmd/issues/2767): \[java] IndexOutOfBoundsException when parsing an initializer BlockStatement
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/errorprone/CloseResourceRule.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/errorprone/CloseResourceRule.java
index cf71010a6a..54e31d0b5d 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/errorprone/CloseResourceRule.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/errorprone/CloseResourceRule.java
@@ -175,7 +175,7 @@ public class CloseResourceRule extends AbstractJavaRule {
         Map<ASTVariableDeclarator, TypeNode> resVars = new HashMap<>();
         for (ASTVariableDeclarator var : vars) {
             TypeNode varType = getTypeOfVariable(var);
-            if (isResourceTypeOrSubtype(varType)) {
+            if (varType != null && isResourceTypeOrSubtype(varType)) {
                 resVars.put(var, wrappedResourceTypeOrReturn(var, varType));
             }
         }
@@ -189,7 +189,7 @@ public class CloseResourceRule extends AbstractJavaRule {
 
     private TypeNode getDeclaredTypeOfVariable(ASTVariableDeclarator var) {
         ASTLocalVariableDeclaration localVar = (ASTLocalVariableDeclaration) var.getParent();
-        return localVar.getTypeNode();
+        return localVar.getTypeNode(); // note: can be null, if type is inferred (var)
     }
 
     private TypeNode getRuntimeTypeOfVariable(ASTVariableDeclarator var) {
diff --git a/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/CloseResource.xml b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/CloseResource.xml
index 440cced230..3dce9a7c49 100644
--- a/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/CloseResource.xml
+++ b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/CloseResource.xml
@@ -1385,6 +1385,27 @@ public class Foo {
         }
         Closeables.close(stream, false);
     }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>[java] [6.27.0] Exception applying rule CloseResource on file ... java.lang.NullPointerException #2755</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+import java.io.*;
+
+public class Foo {
+    public int bar() {
+        var inputStream = getInputStreamFromSomewhere();
+        if (inputStream != null) {
+            try (InputStreamReader reader = new InputStreamReader(inputStream, "UTF-8")) {
+                char c = reader.read();
+                return c;
+            }
+        }
+        return -1;
+    }
 }
         ]]></code>
     </test-code>