Review

Possible null pointer dereference of addingRoot variable.

• missing/condition/null_check

com/google/javascript/jscomp/InstrumentFunctions$InstrumentCallback.java

visit(NodeTraversal, Node, Node)

class InstrumentFunctions.RemoveCallback {
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (NodeUtil.isVarDeclaration(n)) {
        if (removable.contains(n.getString())) {
          parent.removeChild(n);
          if (!parent.hasChildren()) {
            parent.getParent().removeChild(parent);
          }
        }
      }
    }
}

class InstrumentFunctions.InstrumentReturns {
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (n.getType() != Token.RETURN) {
        return;
      }

      Node call = newReportFunctionExitNode();
      Node returnRhs = n.removeFirstChild();
      if (returnRhs != null) {
        call.addChildToBack(returnRhs);
      }
      n.addChildToFront(call);
      compiler.reportCodeChange();
    }
}

class InstrumentFunctions.InstrumentCallback {
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (n.getType() != Token.FUNCTION) {
        return;
      }

      int id = functionNames.getFunctionId(n);
      if (id < 0) {
        // Function node was added during compilation; don't instrument.
        return;
      }

      if (!reportFunctionName.isEmpty()) {
        Node body = n.getFirstChild().getNext().getNext();
        Node call = new Node(Token.CALL,
            Node.newString(Token.NAME, reportFunctionName),
            Node.newNumber(id));
        Node expr = new Node(Token.EXPR_RESULT, call);
        body.addChildToFront(expr);
        compiler.reportCodeChange();
      }

      if (!reportFunctionExitName.isEmpty()) {
        Node body = n.getFirstChild().getNext().getNext();
        (new InstrumentReturns(id)).process(body);
      }

      if (!definedFunctionName.isEmpty()) {
        Node call = new Node(Token.CALL,
            Node.newString(Token.NAME, definedFunctionName),
            Node.newNumber(id));
        Node expr = NodeUtil.newExpr(call);

        Node addingRoot = null;
        if (NodeUtil.isFunctionDeclaration(n)) {
          JSModule module = t.getModule();
          addingRoot = compiler.getNodeForCodeInsertion(module);
          addingRoot.addChildToFront(expr);
        } else {
          Node beforeChild = n;
          for (Node ancestor : n.getAncestors()) {
            int type = ancestor.getType();
            if (type == Token.BLOCK || type == Token.SCRIPT) {
              addingRoot = ancestor;
              break;
            }
            beforeChild = ancestor;
          }
          addingRoot.addChildBefore(expr, beforeChild);
        }
        compiler.reportCodeChange();
      }
    }

}