Merge branch 'pr-5013'

pmd · May 14, 2024 · 3f61843 · 3f61843
2 parents 03f5f1a + 746f64f
commit 3f61843
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Showing 3 changed files with 18 additions and 3 deletions.
diff --git a/docs/pages/release_notes.md b/docs/pages/release_notes.md
@@ -42,6 +42,8 @@ Since this release, PMD will also expose any getter returning a collection of an
   * [#4985](https://github.com/pmd/pmd/issues/4985): \[java] UnusedPrivateMethod false-positive / method reference in combination with custom object
 * java-codestyle
   * [#4930](https://github.com/pmd/pmd/issues/4930): \[java] EmptyControlStatement should not allow empty try with concise resources
+* java-errorprone
+  * [#4042](https://github.com/pmd/pmd/issues/4042): \[java] A false negative about the rule StringBufferInstantiationWithChar
 
 ### 🚨 API Changes
 

diff --git a/pmd-java/src/main/resources/category/java/errorprone.xml b/pmd-java/src/main/resources/category/java/errorprone.xml
@@ -2642,7 +2642,7 @@ public class SomeEJB extends EJBObject implements EJBLocalHome {
     <rule name="StringBufferInstantiationWithChar"
           language="java"
           since="3.9"
-          message="Do not instantiate a StringBuffer or StringBuilder with a char"
+          message="Argument to `new StringBuilder()` or `new StringBuffer()` is implicitly converted from char to int"
           class="net.sourceforge.pmd.lang.rule.xpath.XPathRule"
           externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_errorprone.html#stringbufferinstantiationwithchar">
         <description>
@@ -2668,8 +2668,9 @@ new StringBuilder("A")   //  1 + 16 = 17
             <property name="xpath">
                 <value>
 <![CDATA[
-//ConstructorCall[ArgumentList/CharLiteral]
-    [pmd-java:typeIs('java.lang.StringBuilder') or pmd-java:typeIs('java.lang.StringBuffer')]
+//ConstructorCall[ArgumentList/*[pmd-java:typeIsExactly('char')]]
+    [pmd-java:matchesSig('java.lang.StringBuilder#new(int)')
+     or pmd-java:matchesSig('java.lang.StringBuffer#new(int)')]
 ]]>
                 </value>
             </property>

diff --git a/...s/net/sourceforge/pmd/lang/java/rule/errorprone/xml/StringBufferInstantiationWithChar.xml b/...s/net/sourceforge/pmd/lang/java/rule/errorprone/xml/StringBufferInstantiationWithChar.xml
@@ -29,6 +29,18 @@ public class Foo {
 
 public class Foo2 {
     StringBuilder sb = new StringBuilder('c');
+}
+        ]]></code>
+    </test-code>
+    <test-code>
+        <description>failure case (not a literal)</description>
+        <expected-problems>1</expected-problems>
+        <code><![CDATA[
+
+public class Foo2 {
+    public void foo(char ch) {
+        StringBuilder builder = new StringBuilder(ch);  // should report a warning in this line
+    }
 }
         ]]></code>
     </test-code>