[StatementSwitchToExpressionSwitch] Disable checker when Java21-style…

… case patterns are detected, because these are not currently supported and produce incorrect suggested fixes. In the future, support may be added. PiperOrigin-RevId: 727103506
google · Feb 15, 2025 · 711d705 · 711d705
1 parent dbe6d47
commit 711d705
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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
@@ -245,6 +245,14 @@ private static AnalysisResult analyzeSwitchTree(SwitchTree switchTree, VisitorSt
     // One-pass scan through each case in switch
     for (int caseIndex = 0; caseIndex < cases.size(); caseIndex++) {
       CaseTree caseTree = cases.get(caseIndex);
+      boolean hasCasePattern =
+          caseTree.getLabels().stream()
+              .anyMatch(
+                  caseLabelTree -> caseLabelTree.getKind().name().equals("PATTERN_CASE_LABEL"));
+      if (hasCasePattern) {
+        // Case patterns are not currently supported by the checker.
+        return DEFAULT_ANALYSIS_RESULT;
+      }
       boolean isDefaultCase = caseTree.getExpressions().isEmpty();
       hasDefaultCase |= isDefaultCase;
       // Accumulate enum values included in this case

diff --git a/...rc/test/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitchTest.java b/...rc/test/java/com/google/errorprone/bugpatterns/StatementSwitchToExpressionSwitchTest.java
@@ -17,6 +17,7 @@
 package com.google.errorprone.bugpatterns;
 
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.TruthJUnit.assume;
 
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
@@ -5465,6 +5466,73 @@ String f(int x) {
         .doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
   }
 
+  @Test
+  public void directConversion_casePatternWithGuard_noError() {
+    // Case patterns are not currently supported by the checker.
+    assume().that(Runtime.version().feature()).isAtLeast(21);
+
+    helper
+        .addSourceLines(
+            "Test.java",
+            """
+            class Test {
+
+              int[] x;
+
+              public Test(int foo) {
+                x = null;
+              }
+
+              public int[] foo(String s) {
+                switch (s) {
+                  case String str
+                  when str.equals("good"):
+                    break;
+                  case String str
+                  when str.equals("bad"):
+                    break;
+                  default:
+                    throw new RuntimeException();
+                }
+                return x;
+              }
+            }
+            """)
+        .setArgs("-XepOpt:StatementSwitchToExpressionSwitch:EnableDirectConversion")
+        .doTest();
+  }
+
+  @Test
+  public void directConversion_casePatternWithoutGuard_noError() {
+    // Case patterns are not currently supported by the checker.
+    assume().that(Runtime.version().feature()).isAtLeast(21);
+
+    helper
+        .addSourceLines(
+            "Test.java",
+            """
+            class Test {
+
+              int[] x;
+
+              public Test(int foo) {
+                x = null;
+              }
+
+              public int[] foo(String s) {
+                switch (s) {
+                  case String str:
+                    String[] foo = {"hello", "world"};
+                    break;
+                }
+                return x;
+              }
+            }
+            """)
+        .setArgs("-XepOpt:StatementSwitchToExpressionSwitch:EnableDirectConversion")
+        .doTest();
+  }
+
   /**
    * Asserts that there is exactly one suggested fix and returns it.
    *