Issue #11973: Fix NPE on empty switch statements in VariableDeclarati…

…onUsageDistance
checkstyle · Aug 11, 2022 · 83e8eb9 · 83e8eb9
1 parent af99c7d
commit 83e8eb9
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Showing 3 changed files with 23 additions and 8 deletions.
diff --git a/.../com/puppycrawl/tools/checkstyle/checks/coding/VariableDeclarationUsageDistanceCheck.java b/.../com/puppycrawl/tools/checkstyle/checks/coding/VariableDeclarationUsageDistanceCheck.java
@@ -824,14 +824,16 @@ private static DetailAST getFirstNodeInsideSwitchBlock(
         final List<DetailAST> variableUsageExpressions =
                 new ArrayList<>();
 
-        // Checking variable usage inside all CASE_GROUP and SWITCH_RULE ast's.
-        TokenUtil.forEachChild(block, currentNode.getType(), node -> {
-            final DetailAST lastNodeInCaseGroup =
-                node.getLastChild();
-            if (isChild(lastNodeInCaseGroup, variable)) {
-                variableUsageExpressions.add(lastNodeInCaseGroup);
-            }
-        });
+        if (currentNode != null) {
+            // Checking variable usage inside all CASE_GROUP and SWITCH_RULE ast's.
+            TokenUtil.forEachChild(block, currentNode.getType(), node -> {
+                final DetailAST lastNodeInCaseGroup =
+                        node.getLastChild();
+                if (isChild(lastNodeInCaseGroup, variable)) {
+                    variableUsageExpressions.add(lastNodeInCaseGroup);
+                }
+            });
+        }
 
         // If variable usage exists in several related blocks, then
         // firstNodeInsideBlock = null, otherwise if variable usage exists

diff --git a/...coding/variabledeclarationusagedistance/InputVariableDeclarationUsageDistanceDefault.java b/...coding/variabledeclarationusagedistance/InputVariableDeclarationUsageDistanceDefault.java
@@ -1071,4 +1071,10 @@ private void n() {
         New6.field = (int)a;
     }
 
+    class SwitchStatement {
+        void issue11973() {
+            int i = -1;
+            switch (i) { } // ok
+        }
+    }
 }
diff --git a/...coding/variabledeclarationusagedistance/InputVariableDeclarationUsageDistanceGeneral.java b/...coding/variabledeclarationusagedistance/InputVariableDeclarationUsageDistanceGeneral.java
@@ -1070,4 +1070,11 @@ private void n() {
         New1.field = 3;
         New1.field = (int)a;
     }
+
+    class SwitchStatement {
+        void issue11973() {
+            int i = -1;
+            switch (i) { } // ok
+        }
+    }
 }