Short-circuit StatementSwitchToExpressionSwitch analysis when present…

…ed with expression switch; add non-empty expression switch test case PiperOrigin-RevId: 499480786
google · Jan 4, 2023 · a604633 · a604633
1 parent 836caf2
commit a604633
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Showing 2 changed files with 24 additions and 2 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitch.java b/core/src/main/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitch.java
@@ -124,7 +124,12 @@ private static AnalysisResult analyzeSwitchTree(SwitchTree switchTree) {
 
       List<? extends StatementTree> statements = caseTree.getStatements();
       CaseFallThru caseFallThru = CaseFallThru.MAYBE_FALLS_THRU;
-      if (statements == null || statements.isEmpty()) {
+      if (statements == null) {
+        // This case must be of kind CaseTree.CaseKind.RULE, and thus this is already an expression
+        // switch; no need to continue analysis.
+        return AnalysisResult.of(
+            /* canConvertDirectlyToExpressionSwitch= */ false, ImmutableList.of());
+      } else if (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
@@ -1017,7 +1017,7 @@ public void singleCaseConvertible_error() {
   }
 
   @Test
-  public void emptySwitchCases_noMatch() {
+  public void emptyExpressionSwitchCases_noMatch() {
     assumeTrue(RuntimeVersion.isAtLeast14());
     helper
         .addSourceLines(
@@ -1033,6 +1033,23 @@ public void emptySwitchCases_noMatch() {
         .doTest();
   }
 
+  @Test
+  public void nonEmptyExpressionSwitchCases_noMatch() {
+    assumeTrue(RuntimeVersion.isAtLeast14());
+    helper
+        .addSourceLines(
+            "Test.java",
+            "class Test {",
+            "  void foo(int value) { ",
+            "    switch (value) {",
+            "      case 0 -> System.out.println(\"zero\");",
+            "      default -> {System.out.println(\"non-zero\");}",
+            "    }",
+            "  }",
+            "}")
+        .doTest();
+  }
+
   @Test
   public void dynamicWithThrowableDuringInitializationFromMethod_noMatch() {
     assumeTrue(RuntimeVersion.isAtLeast14());