Merge branch 'master' into pmd/7.0.x

.all-contributorsrc

@@ -6529,6 +6529,15 @@
       "contributions": [
         "code"
       ]
+    },
+    {
+      "login": "gredler",
+      "name": "Daniel Gredler",
+      "avatar_url": "https://avatars.githubusercontent.com/u/178883?v=4",
+      "profile": "https://github.com/gredler",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 7,

docs/pages/release_notes.md

@@ -57,8 +57,11 @@ not support all features of the latest EcmaScript standard.
     *   [#3644](https://github.com/pmd/pmd/issues/3644): \[java] InvalidLogMessageFormat: false positives with logstash structured logging
     *   [#3686](https://github.com/pmd/pmd/issues/3686): \[java] ReturnEmptyCollectionRatherThanNull - false negative with conditioned returns
     *   [#3701](https://github.com/pmd/pmd/issues/3701): \[java] MissingStaticMethodInNonInstantiatableClass false positive with method inner classes
+    *   [#3721](https://github.com/pmd/pmd/issues/3721): \[java] ReturnEmptyCollectionRatherThanNull - false positive with stream and lambda
 *   java-performance
     *   [#3492](https://github.com/pmd/pmd/issues/3492): \[java] UselessStringValueOf: False positive when there is no initial String to append to
+    *   [#3639](https://github.com/pmd/pmd/issues/3639): \[java] UseStringBufferLength: false negative with empty string variable
+    *   [#3712](https://github.com/pmd/pmd/issues/3712): \[java] InsufficientStringBufferDeclaration false positive with StringBuilder.setLength(0)
 *   javascript
     *   [#3703](https://github.com/pmd/pmd/issues/3703): \[javascript] Error - no Node adapter class registered for XmlPropRef
 
@@ -74,9 +77,11 @@ not support all features of the latest EcmaScript standard.
 *   [#3713](https://github.com/pmd/pmd/pull/3713): \[java] Enhance UnnecessaryModifier to support records - [Vincent Galloy](https://github.com/vgalloy)
 *   [#3719](https://github.com/pmd/pmd/pull/3719): \[java] Upgrade log4j to 2.17.1 - [Daniel Paul Searles](https://github.com/squaresurf)
 *   [#3720](https://github.com/pmd/pmd/pull/3720): \[java] New rule: FinalParameterInAbstractMethod - [Vincent Galloy](https://github.com/vgalloy)
-*   [#3724](https://github.com/pmd/pmd/pull/3724): \[java] Fix for #3686 - fix FinalFieldCouldBeStatic - [Oleksii Dykov](https://github.com/dykov)
+*   [#3724](https://github.com/pmd/pmd/pull/3724): \[java] Fix for #3679 - fix FinalFieldCouldBeStatic - [Oleksii Dykov](https://github.com/dykov)
+*   [#3727](https://github.com/pmd/pmd/pull/3727): \[java] #3724 - fix FinalFieldCouldBeStatic: triggers only if the referenced name is static - [Oleksii Dykov](https://github.com/dykov)
 *   [#3742](https://github.com/pmd/pmd/pull/3742): \[java] Fix #3701 - fix MissingStaticMethodInNonInstantiatableClass for method local classes - [Oleksii Dykov](https://github.com/dykov)
 *   [#3744](https://github.com/pmd/pmd/pull/3744): \[core] Updated SaxonXPathRuleQueryTest.java - [Vyom Yadav](https://github.com/Vyom-Yadav)
+*   [#3745](https://github.com/pmd/pmd/pull/3745): \[java] Fix #3712: InsufficientStringBufferDeclaration setLength false positive - [Daniel Gredler](https://github.com/gredler)
 
 {% endtocmaker %}
 

pmd-doc/src/main/java/net/sourceforge/pmd/docs/DeadLinksChecker.java

@@ -221,7 +221,6 @@ public class DeadLinksChecker {
     }
 
 
-    @SuppressWarnings("PMD.ReturnEmptyCollectionRatherThanNull")
     private Map<Path, List<String>> joinFutures(Map<Path, List<Future<String>>> map) {
         Map<Path, List<String>> joined = new HashMap<>();
 

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/performance/InsufficientStringBufferDeclarationRule.java

@@ -141,7 +141,7 @@ public class InsufficientStringBufferDeclarationRule extends AbstractJavaRulecha
             } else if (usage.getParent() instanceof ASTAssignmentExpression) {
                 ASTAssignmentExpression assignment = (ASTAssignmentExpression) usage.getParent();
                 State newState = getConstructorCapacity(node, assignment.getRightOperand());
-                
+
                 if (newState.rootNode != null) {
                     if (state.isInsufficient()) {
                         addViolation(data, state.rootNode, state.getParamsForViolation());

pmd-java/src/main/resources/category/java/design.xml

@@ -783,7 +783,8 @@ in each object at runtime.
     [pmd-java:modifiers() = 'final']
     [not(pmd-java:modifiers() = 'static')]
     [not(.//Annotation[pmd-java:typeIs('lombok.Builder.Default')])]
-    /VariableDeclarator[NumericLiteral or StringLiteral or CharLiteral or BooleanLiteral or NullLiteral or VariableAccess or FieldAccess]
+    /VariableDeclarator[NumericLiteral or StringLiteral or CharLiteral or BooleanLiteral or NullLiteral
+         or VariableAccess or FieldAccess]
     /VariableDeclaratorId
 ]]>
                 </value>

pmd-java/src/main/resources/category/java/errorprone.xml

@@ -2648,11 +2648,12 @@ See Effective Java, 3rd Edition, Item 54: Return empty collections or arrays ins
             <property name="xpath">
                 <value>
 <![CDATA[
-//MethodDeclaration
+//ReturnStatement/NullLiteral
+[ancestor::MethodDeclaration[1]
     [ArrayType
      or ClassOrInterfaceType[pmd-java:typeIs('java.util.Collection')
         or pmd-java:typeIs('java.util.Map')]]
-//ReturnStatement/NullLiteral
+]
 [not(./ancestor::LambdaExpression)]
 [not(./ancestor::AnonymousClassDeclaration)]
 ]]>

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/design/xml/FinalFieldCouldBeStatic.xml

@@ -175,6 +175,24 @@ class Clazz {
         <code><![CDATA[
 class Clazz {
   public final int a = getValue();
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>
+            #3724 - the rule should be triggered only if the referenced name is static
+        </description>
+        <expected-problems>1</expected-problems>
+        <expected-linenumbers>7</expected-linenumbers>
+        <code><![CDATA[
+public class Foo {
+    private int nonStaticPrivate = 1;                   //no violation cause non-final
+    private final int nonStatic = nonStaticPrivate;     //no violation cause referenced name is non-static
+
+    //private static final int staticFinal = nonStatic; //noncompliant: Non-static field 'nonStatic' cannot be referenced from a static context
+    private static int staticNonFinal = 1;              //no violation cause non-final
+    private final int nonStatic2 = staticNonFinal;      //violation because it could be static
 }
         ]]></code>
     </test-code>

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/errorprone/xml/ReturnEmptyCollectionRatherThanNull.xml

@@ -179,4 +179,55 @@ public class Foo {
   }
     ]]></code>
   </test-code>
+
+  <test-code>
+    <description>[java] ReturnEmptyCollectionRatherThanNull - false positive with stream and lambda #3721</description>
+    <expected-problems>1</expected-problems>
+    <expected-linenumbers>37</expected-linenumbers>
+    <code><![CDATA[
+import java.util.*;
+import java.util.concurrent.Callable;
+
+public class Foo {
+    private Map<Path, List<String>> joinFutures(Map<String, List<Future<String>>> map) {
+        Map<String, List<String>> joined = new HashMap<>();
+
+        for (String p : map.keySet()) {
+            List<String> evaluatedResult = map.get(p).stream()
+                                              .map(f -> {
+                                                  try {
+                                                      return f.get();
+                                                  } catch (InterruptedException | ExecutionException e) {
+                                                      e.printStackTrace();
+                                                      return null; // <----- false positive here
+                                                  }
+                                              })
+                                              .filter(Objects::nonNull)
+                                              .sorted(Comparator.naturalOrder())
+                                              .collect(Collectors.toList());
+
+            if (!evaluatedResult.isEmpty()) {
+                joined.put(p, evaluatedResult);
+            }
+        }
+
+        // checking basic lambdas and anonymous classes as well
+        Callable<Object> c = a -> { return null; }; // <----- false positive here
+        Callable<Object> c2 = new Callable<Object>() {
+            public Object call() {
+                return null; // <----- false positive here
+            }
+        };
+
+        Callable<List<String>> c3 = new Callable<List<String>>() {
+            public List<String> call() {
+                return null;
+            }
+        };
+
+        return joined;
+    }
+}
+    ]]></code>
+  </test-code>
 </test-data>

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/performance/xml/InsufficientStringBufferDeclaration.xml

@@ -1220,13 +1220,14 @@ public class FalsePositive {
 
     <test-code>
         <description>Calculated initial size in constructor</description>
-        <expected-problems>4</expected-problems>
-        <expected-linenumbers>10,34,44,61</expected-linenumbers>
+        <expected-problems>5</expected-problems>
+        <expected-linenumbers>10,34,44,61,88</expected-linenumbers>
         <expected-messages>
             <message>StringBuilder has been initialized with size 4, but has at least 5 characters appended.</message>
             <message>StringBuilder has been initialized with size 5, but has at least 6 characters appended.</message>
             <message>StringBuilder has been initialized with size 8, but has at least 10 characters appended.</message>
             <message>StringBuilder has been initialized with size 8, but has at least 9 characters appended.</message>
+            <message>StringBuilder has been initialized with size 7, but has at least 8 characters appended.</message>
         </expected-messages>
         <code><![CDATA[
 public class InsufficientStringBufferDeclaration {
@@ -1296,6 +1297,30 @@ public class InsufficientStringBufferDeclaration {
         sb.append('d'); // length is now 9
         return sb.toString();
     }
+
+    public String case9_sufficient_setLength() {
+        StringBuilder sb = new StringBuilder(4);
+        sb.append("xxxx");
+        sb.setLength(0); // length is 0, capacity is still 4
+        sb.append("aaaa");
+        return sb.toString();
+    }
+
+    public String case10_unknown_setLength(String in) {
+        StringBuilder sb = new StringBuilder(in.length()); // unknown
+        sb.append("xxxx");
+        sb.setLength(0); // length is 0, capacity is still unknown
+        sb.append("aaaa");
+        return sb.toString();
+    }
+
+    public String case11_unknown_ensureCapacity(String in) {
+        StringBuilder sb = new StringBuilder(in.length()); // unknown
+        sb.append("xxxx"); // length is 4
+        sb.ensureCapacity(7); // line 88 - length is still 4, new capacity now at least 7 -> violation here
+        sb.append("aaaa"); // length is 8
+        return sb.toString();
+    }
 }
         ]]></code>
     </test-code>

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/performance/xml/UseStringBufferLength.xml

@@ -189,6 +189,28 @@ public class Ineffecient
     {
         return "Ineffecient";
     }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>[java] UseStringBufferLength: false negative with empty string variable #3639</description>
+        <expected-problems>1</expected-problems>
+        <expected-linenumbers>5</expected-linenumbers>
+        <code><![CDATA[
+public class Foo {
+    public void foo() {
+        StringBuffer sb = new StringBuffer("any_string");
+        final String nullStr = "";
+        if (sb.toString().equals(nullStr)) { // PMD should report a warning here
+            System.out.println("Buffer is empty");
+        }
+
+        // the preferred way
+        if (sb.length() == 0) {
+            System.out.println("Buffer is empty");
+        }
+    }
 }
         ]]></code>
     </test-code>