Fix an NPE on case null in MissingCasesInEnumSwitch

Fixes #4684 PiperOrigin-RevId: 698055266
google · Nov 19, 2024 · 150334e · 150334e
1 parent e840c2e
commit 150334e
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Showing 2 changed files with 40 additions and 2 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/MissingCasesInEnumSwitch.java b/core/src/main/java/com/google/errorprone/bugpatterns/MissingCasesInEnumSwitch.java
@@ -18,7 +18,6 @@
 
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
-import static com.google.errorprone.util.ASTHelpers.getSymbol;
 import static com.google.errorprone.util.ASTHelpers.isSwitchDefault;
 
 import com.google.common.collect.ImmutableSet;
@@ -60,7 +59,9 @@ public Description matchSwitch(SwitchTree tree, VisitorState state) {
     ImmutableSet<String> handled =
         cases.stream()
             .flatMap(c -> c.getExpressions().stream())
-            .map(e -> getSymbol(e).getSimpleName().toString())
+            .map(ASTHelpers::getSymbol)
+            .filter(x -> x != null)
+            .map(symbol -> symbol.getSimpleName().toString())
             .collect(toImmutableSet());
     Set<String> unhandled = Sets.difference(ASTHelpers.enumValues(switchType.asElement()), handled);
     if (unhandled.isEmpty()) {

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/MissingCasesInEnumSwitchTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/MissingCasesInEnumSwitchTest.java
@@ -309,4 +309,41 @@ void m(Case c) {
             """)
         .doTest();
   }
+
+  @Test
+  public void i4684() {
+    assume().that(Runtime.version().feature()).isAtLeast(21);
+    compilationHelper
+        .addSourceLines(
+            "ErrorProneBug.java",
+            """
+            public class ErrorProneBug {
+              enum A {
+                A1,
+                A2,
+                A3
+              }
+
+              public static void main(String[] args) {
+                A a = null;
+
+                switch (a) {
+                  case null -> {
+                    System.out.println("null");
+                  }
+                  case A1 -> {
+                    System.out.println("A1");
+                  }
+                  case A2 -> {
+                    System.out.println("A2");
+                  }
+                  case A3 -> {
+                    System.out.println("A3");
+                  }
+                }
+              }
+            }
+            """)
+        .doTest();
+  }
 }