#fixed code
                                public boolean readOne() {
        try (DocumentContext context = in.readingDocument()) {
            if (!context.isPresent())
                return false;
            if (context.isMetaData())
                return readOneMetaData(context);

            assert context.isData();

            messageHistory.reset(context.sourceId(), context.index());
            wireParser.accept(context.wire());
        }
        return true;
    }
#vulnerable code 
                                public boolean readOne() {
        for (; ; ) {

            try (DocumentContext context = in.readingDocument()) {
                if (!context.isPresent())
                    return false;
                if (context.isMetaData()) {
                    StringBuilder sb = Wires.acquireStringBuilder();

                    long r = context.wire().bytes().readPosition();
                    try {
                        context.wire().readEventName(sb);

                        for (String s : metaIgnoreList) {
                            // we wish to ignore our system meta data field
                            if (s.contentEquals(sb))
                                return false;
                        }
                    } finally {
                        // roll back position to where is was before we read the SB
                        context.wire().bytes().readPosition(r);
                    }

                    wireParser.accept(context.wire());

                    return true;
                }
                if (!context.isData())
                    continue;
                MessageHistory history = messageHistory;
                history.reset(context.sourceId(), context.index());
                wireParser.accept(context.wire());
            }
            return true;
        }

    } 
                            #location 10 
                            #vulnerability type NULL_DEREFERENCE