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  1. JDK
  2. JDK-6472751

SourcePositions.getStartPos returns incorrect value for enum constants

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 6
    • Fix Version/s: 7
    • Component/s: tools
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b81
    • CPU:
      generic
    • OS:
      generic
    • Verification:
      Verified

      Description

      SourcePositions.getStartPos() incorrectly returns -1 for enum constants. TreeInfo.java line 288 has:

      case(JCTree.VARDEF): {
      JCVariableDecl node = (JCVariableDecl)tree;
      if (node.mods.pos != Position.NOPOS) {
      return node.mods.pos;
      } else {
      return getStartPos(node.vartype);
      }

      and you can see why it doesn't work for enum constants.
      I'm lazy, so let me try to explain the problem one more time. If you still think you need a test case, I'll consider writing one.

      The problem happens when I'm looking at the tree of enum constant declaration, like "ABC" of:

        enum E { ABC, DEF; }

      Javac creates JCTree.JCVariableDecl node for 'ABC' (and 'DEF') Unlike other 'ordinary' field declarations or local variable declarations, this JCVariableDecl doesn't have the JCVariableDecl#vartype set. So when I try to access the start position of this JCVariableDecl, the following code runs:

      case(JCTree.VARDEF): {
      JCVariableDecl node = (JCVariableDecl)tree;
      if (node.mods.pos != Position.NOPOS) {
      return node.mods.pos;
      } else {
      return getStartPos(node.vartype);
      }

      and I get NOPOS. The correct code should be:

      case(JCTree.VARDEF): {
      JCVariableDecl node = (JCVariableDecl)tree;
      if (node.mods.pos != Position.NOPOS) {
      return node.mods.pos;
      }
                  if(node.vartype!=null) {
      return getStartPos(node.vartype);
      }
                  return node.sym.pos;
      import com.sun.source.tree.CompilationUnitTree;
      import com.sun.source.tree.Tree;
      import com.sun.source.util.JavacTask;
      import com.sun.source.util.SourcePositions;
      import com.sun.source.util.TreeScanner;
      import com.sun.source.util.Trees;
      import com.sun.tools.javac.util.List;
      import java.io.IOException;
      import java.net.URI;
      import javax.tools.JavaCompiler;
      import javax.tools.JavaFileObject;
      import javax.tools.SimpleJavaFileObject;
      import javax.tools.ToolProvider;

      public class T6472751 {
          static class MyFileObject extends SimpleJavaFileObject {
              public MyFileObject() {
                  super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
              }
              public CharSequence getCharContent(boolean ignoreEncodingErrors) {
                  return "public enum Test { ABC, DEF; }";
              }
          }
          static Trees trees;
          static SourcePositions positions;
          public static void main(String[] args) throws IOException {
              JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
              JavacTask task = (JavacTask) compiler.getTask(null, null, null, null, null, List.of(new MyFileObject()));
              trees = Trees.instance(task);
              positions = trees.getSourcePositions();
              Iterable<? extends CompilationUnitTree> asts = task.parse();
              for (CompilationUnitTree ast : asts) {
                  new MyVisitor().scan(ast, null);
              }
          }
          
          static class MyVisitor extends TreeScanner<Void,Void> {
              @Override
              public Void scan(Tree node, Void ignored) {
                  if (node == null)
                      return null;
                  System.out.format("%s: %s%n", node.getKind(), positions.getStartPosition(null,node));
                  return super.scan(node, ignored);
              }

          }
      }

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              • Assignee:
                jjg Jonathan Gibbons
                Reporter:
                kkawagucsunw Kohsuke Kawaguchi (Inactive)
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                • Created:
                  Updated:
                  Resolved:
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