Don't crash when someone declares a StringBuffer using var.

PiperOrigin-RevId: 449835264
google · May 19, 2022 · 97a7dbc · 97a7dbc
1 parent 9ff2d42
commit 97a7dbc
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Showing 2 changed files with 30 additions and 5 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/JdkObsolete.java b/core/src/main/java/com/google/errorprone/bugpatterns/JdkObsolete.java
@@ -60,6 +60,7 @@
 import com.sun.tools.javac.code.Symbol.VarSymbol;
 import com.sun.tools.javac.code.Type;
 import com.sun.tools.javac.code.Types;
+import com.sun.tools.javac.util.Position;
 import java.util.Optional;
 import javax.annotation.Nullable;
 
@@ -344,11 +345,13 @@ public Void visitIdentifier(IdentifierTree tree, Void unused) {
  if (escape[0]) {
  return Optional.empty();
  }
- return Optional.of(
- SuggestedFix.builder()
- .replace(newClassTree.getIdentifier(), "StringBuilder")
- .replace(varTree.getType(), "StringBuilder")
- .build());
+ SuggestedFix.Builder fix =
+ SuggestedFix.builder().replace(newClassTree.getIdentifier(), "StringBuilder");
+ if (ASTHelpers.getStartPosition(varTree.getType()) != Position.NOPOS) {
+ // If the variable is declared with `var`, there's no declaration type to change
+ fix = fix.replace(varTree.getType(), "StringBuilder");
+ }
+ return Optional.of(fix.build());
  }
 
  private static TreePath findEnclosingMethod(VisitorState state) {

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/JdkObsoleteTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/JdkObsoleteTest.java
@@ -161,6 +161,28 @@ public void stringBufferRefactoringTest() {
  .doTest();
  }
 
+ @Test
+ public void stringBufferRefactoringTest_usingVar() {
+ BugCheckerRefactoringTestHelper.newInstance(JdkObsolete.class, getClass())
+ .addInputLines(
+ "in/Test.java", //
+ "class Test {",
+ " String f() {",
+ " var sb = new StringBuffer();",
+ " return sb.append(42).toString();",
+ " }",
+ "}")
+ .addOutputLines(
+ "out/Test.java", //
+ "class Test {",
+ " String f() {",
+ " var sb = new StringBuilder();",
+ " return sb.append(42).toString();",
+ " }",
+ "}")
+ .doTest();
+ }
+
  /** A test input. */
  public interface Lib {
  Enumeration<Integer> foos();