StatementSwitchToExpressionSwitch: handle empty statement blocks

Fixes google#3638. Fixes google#3645 COPYBARA_INTEGRATE_REVIEW=google#3645 from PicnicSupermarket:bugfix/issue-3638 773f647 PiperOrigin-RevId: 498743647 (cherry picked from commit 96cd000)
PicnicSupermarket · Jan 2, 2023 · 39ad964 · 39ad964
1 parent fc81ded
commit 39ad964
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diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitch.java b/core/src/main/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitch.java
@@ -122,7 +122,7 @@ private static AnalysisResult analyzeSwitchTree(SwitchTree switchTree) {
 
       List<? extends StatementTree> statements = caseTree.getStatements();
       CaseFallThru caseFallThru = CaseFallThru.MAYBE_FALLS_THRU;
-      if (statements.isEmpty()) {
+      if (statements == null || statements.isEmpty()) {
         // If the code for this case is just an empty block, then it must fall thru
         caseFallThru = CaseFallThru.DEFINITELY_DOES_FALL_THRU;
         // Can group with the next case (unless this is the last case)

diff --git a/...rc/test/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitchTest.java b/...rc/test/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitchTest.java
@@ -1016,6 +1016,23 @@ public void singleCaseConvertible_error() {
         .doTest();
   }
 
+  @Test
+  public void emptySwitchCases_noMatch() {
+    assumeTrue(RuntimeVersion.isAtLeast14());
+    helper
+        .addSourceLines(
+            "Test.java",
+            "class Test {",
+            "  void foo(int value) { ",
+            "    switch (value) {",
+            "      case 0 -> {}",
+            "      default -> {}",
+            "    }",
+            "  }",
+            "}")
+        .doTest();
+  }
+
   @Test
   public void dynamicWithThrowableDuringInitializationFromMethod_noMatch() {
     assumeTrue(RuntimeVersion.isAtLeast14());