Review

Iterator.next() is invoked without prior check that the iterator has more elements.

• missing/condition/value_or_state

com/google/javascript/jscomp/ReplaceMessages.java

constructStringExprNode(Iterator, Node)

class ReplaceMessages {
  /**
   * Creates a parse tree corresponding to the remaining message parts in an
   * iteration. The result consists of one or more STRING nodes, placeholder
   * replacement value nodes (which can be arbitrary expressions), and ADD
   * nodes.
   *
   * @param parts  an iterator over message parts
   * @param objLitNode  an OBJLIT node mapping placeholder names to values
   * @return the root of the constructed parse tree
   *
   * @throws MalformedException if {@code parts} contains a placeholder
   *   reference that does not correspond to a valid placeholder name
   */
  private Node constructStringExprNode(Iterator<CharSequence> parts,
      Node objLitNode) throws MalformedException {

    CharSequence part = parts.next();
    Node partNode = null;
    if (part instanceof JsMessage.PlaceholderReference) {
      JsMessage.PlaceholderReference phRef =
          (JsMessage.PlaceholderReference) part;

      for (Node key = objLitNode.getFirstChild(); key != null;
           key = key.getNext()) {
        if (key.getString().equals(phRef.getName())) {
          Node valueNode = key.getFirstChild();
          partNode = valueNode.cloneTree();
        }
      }

      if (partNode == null) {
        throw new MalformedException(
            "Unrecognized message placeholder referenced: " + phRef.getName(),
            objLitNode);
      }
    } else {
      // The part is just a string literal.
      partNode = Node.newString(part.toString());
    }

    if (parts.hasNext()) {
      return new Node(Token.ADD, partNode,
          constructStringExprNode(parts, objLitNode));
    } else {
      return partNode;
    }
  }

}