[java] TooFewBranchesForSwitch - allow list of case constants (#5289)

docs/pages/release_notes.md

@@ -29,6 +29,7 @@ This is a {{ site.pmd.release_type }} release.
   * [#5083](https://github.com/pmd/pmd/issues/5083): \[java] UnusedPrivateMethod false positive when method reference has no target type
   * [#5318](https://github.com/pmd/pmd/issues/5318): \[java] PreserveStackTraceRule: false-positive on Pattern Matching with instanceof
 * java-performance
+  * [#5287](https://github.com/pmd/pmd/issues/5287): \[java] TooFewBranchesForSwitch false-positive with switch using list of case constants
   * [#5314](https://github.com/pmd/pmd/issues/5314): \[java] InsufficientStringBufferDeclarationRule: Lack of handling for char type parameters
 
 ### 🚨 API Changes

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

@@ -629,7 +629,7 @@ Note: This rule was named TooFewBranchesForASwitchStatement before PMD 7.7.0.
                 <value>
 <![CDATA[
 //(SwitchStatement | SwitchExpression)
-  [ (count(*) - 1) < $minimumNumberCaseForASwitch ]
+  [ (count(*/SwitchLabel/*) + count(*/SwitchLabel[@Default = true()])) < $minimumNumberCaseForASwitch ]
   (: only consider if no pattern matching is used :)
   [*/SwitchLabel[@PatternLabel = false()]]
 ]]>

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

@@ -136,6 +136,68 @@ public class SwitchWithRecordPattern {
         }
     }
 }
+]]></code>
+    </test-code>
+
+    <test-code>
+        <description>#5287 [java] TooFewBranchesForSwitch false-positive with switch using list of case constants</description>
+        <rule-property name="minimumNumberCaseForASwitch">3</rule-property>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+enum SomeEnum { A, B, C, D }
+class Tester {
+    int checkSwitchExpression(SomeEnum someEnumValue) {
+        return switch(someEnumValue) {
+            case A, B, C -> 1;
+            default -> 0;
+        };
+    }
+
+    int checkSwitchStatement(SomeEnum someEnumValue) {
+        int result;
+        switch(someEnumValue) {
+            case A, B, C -> { result = 1; }
+            default -> { result = 0; }
+        }
+        return result;
+    }
+
+    int checkSwitchExpressionGroup(SomeEnum someEnumValue) {
+        return switch(someEnumValue) {
+            case A, B, C: yield 1;
+            default: yield 0;
+        };
+    }
+
+    int checkSwitchStatementGroup(SomeEnum someEnumValue) {
+        int result;
+        switch(someEnumValue) {
+            case A, B, C: result = 1; break;
+            default: result = 0; break;
+        }
+        return result;
+    }
+}
+]]></code>
+    </test-code>
+
+    <test-code>
+        <description>From #5311: Another example for list of case constants</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class Foo {
+
+  String foo(Bar bar) {
+    return switch (bar) {
+      case A, B, C, D -> "Hello";
+      case E, F, G -> "World";
+    };
+  }
+
+  enum Bar {
+    A, B, C, D, E, F, G
+  }
+}
 ]]></code>
     </test-code>
 </test-data>