DuplicateBranches: don't crash on empty blocks

PiperOrigin-RevId: 692998546
google · Nov 4, 2024 · b02e05b · b02e05b
1 parent d173d85
commit b02e05b
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Showing 2 changed files with 31 additions and 2 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/DuplicateBranches.java b/core/src/main/java/com/google/errorprone/bugpatterns/DuplicateBranches.java
@@ -76,8 +76,12 @@ private Description match(Tree tree, Tree thenTree, Tree elseTree, VisitorState
     if (elseTree instanceof BlockTree) {
       needsBraces = !state.getPath().getParentPath().getLeaf().getKind().equals(Kind.BLOCK);
       var statements = ((BlockTree) elseTree).getStatements();
-      start = getStartPosition(statements.get(0));
-      end = state.getEndPosition(getLast(statements));
+      if (statements.isEmpty()) {
+        start = end;
+      } else {
+        start = getStartPosition(statements.get(0));
+        end = state.getEndPosition(getLast(statements));
+      }
     }
     String comments =
         ErrorProneTokens.getTokens(

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/DuplicateBranchesTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/DuplicateBranchesTest.java
@@ -215,4 +215,29 @@ boolean g(boolean a, boolean b) {
             """)
         .doTest(TestMode.TEXT_MATCH);
   }
+
+  @Test
+  public void negativeEmpty() {
+    BugCheckerRefactoringTestHelper.newInstance(DuplicateBranches.class, getClass())
+        .addInputLines(
+            "Test.java",
+            """
+            class Test {
+              void f(boolean a) {
+                if (a) {
+                } else {
+                }
+              }
+            }
+            """)
+        .addOutputLines(
+            "Test.java",
+            """
+            class Test {
+              void f(boolean a) {
+              }
+            }
+            """)
+        .doTest();
+  }
 }