k线图第一课k线为空是报错，但是后面的k线为空时正常有一个k线缺失

[zjqzero]

One-line summary [问题简述]

在一下特定场景需要插入空K线，最近更新了echarts版本后，发现如果第一个k线为空时报错；只要不是第一颗k线为空就没有问题，错误如下

echarts.min.js:32 Uncaught (in promise) TypeError: Cannot read property 'sign' of undefined
    at y.<anonymous> (echarts.min.js:32)
    at y.x.each (echarts.min.js:11)
    at echarts.min.js:32
    at Array.forEach (<anonymous>)
    at f (echarts.min.js:1)
    at i.eachRawSeriesByType (echarts.min.js:26)
    at Object.t.exports [as func] (echarts.min.js:32)
    at echarts.min.js:1
    at Array.forEach (<anonymous>)

Version & Environment [版本及环境]

• ECharts version [ECharts 版本]: 3.6.2
• Browser version [浏览器类型和版本]: chrome Version 59.0.3071.104
• OS Version [操作系统类型和版本]: ubuntu 16.04

Expected behaviour [期望结果]

第一颗空k线不报错，时间序列上存在，k线不存在，不画在图上，留下空白

ECharts option [ECharts配置项]

var data0 = splitData([
    ['2013/1/24'],
    ['2013/1/25', 2300,2291.3,2288.26,2308.38],
    ['2013/1/28', 2295.35,2346.5,2295.35,2346.92],
    ['2013/1/29', 2347.22,2358.98,2337.35,2363.8],
    ['2013/1/30'],
    ['2013/1/31', 2383.43,2385.42,2371.23,2391.82],
    ['2013/2/1', 2377.41,2419.02,2369.57,2421.15],
    ['2013/2/4', 2425.92,2428.15,2417.58,2440.38],
    ['2013/2/5', 2411,2433.13,2403.3,2437.42],
    ['2013/2/6', 2432.68,2434.48,2427.7,2441.73],
    ['2013/2/7', 2430.69,2418.53,2394.22,2433.89],
    ['2013/2/8', 2416.62,2432.4,2414.4,2443.03],
    ['2013/2/18', 2441.91,2421.56,2415.43,2444.8],
    ['2013/2/19', 2420.26,2382.91,2373.53,2427.07],
    ['2013/2/20', 2383.49,2397.18,2370.61,2397.94],
    ['2013/2/21', 2378.82,2325.95,2309.17,2378.82],
    ['2013/2/22', 2322.94,2314.16,2308.76,2330.88]
]);

option = {
    title: {
        text: '上证指数',
        left: 0
    },
    tooltip: {
        trigger: 'axis',
        axisPointer: {
            type: 'cross'
        }
    },
    legend: {
        data: ['日K', 'MA5', 'MA10', 'MA20', 'MA30']
    },
    grid: {
        left: '10%',
        right: '10%',
        bottom: '15%'
    },
    xAxis: {
        type: 'category',
        data: data0.categoryData,
        scale: true,
        boundaryGap : false,
        axisLine: {onZero: false},
        splitLine: {show: false},
        splitNumber: 20,
        min: 'dataMin',
        max: 'dataMax'
    },
    yAxis: {
        scale: true,
        splitArea: {
            show: true
        }
    },
    dataZoom: [
        {
            type: 'inside',
            start: 50,
            end: 100
        },
        {
            show: true,
            type: 'slider',
            y: '90%',
            start: 50,
            end: 100
        }
    ],
    series: [
        {
            name: '日K',
            type: 'candlestick',
            data: data0.values,
            markPoint: {
                label: {
                    normal: {
                        formatter: function (param) {
                            return param != null ? Math.round(param.value) : '';
                        }
                    }
                },
                data: [
                    {
                        name: 'XX标点',
                        coord: ['2013/5/31', 2300],
                        value: 2300,
                        itemStyle: {
                            normal: {color: 'rgb(41,60,85)'}
                        }
                    },
                    {
                        name: 'highest value',
                        type: 'max',
                        valueDim: 'highest'
                    },
                    {
                        name: 'lowest value',
                        type: 'min',
                        valueDim: 'lowest'
                    },
                    {
                        name: 'average value on close',
                        type: 'average',
                        valueDim: 'close'
                    }
                ],
                tooltip: {
                    formatter: function (param) {
                        return param.name + '<br>' + (param.data.coord || '');
                    }
                }
            },
            markLine: {
                symbol: ['none', 'none'],
                data: [
                    [
                        {
                            name: 'from lowest to highest',
                            type: 'min',
                            valueDim: 'lowest',
                            symbol: 'circle',
                            symbolSize: 10,
                            label: {
                                normal: {show: false},
                                emphasis: {show: false}
                            }
                        },
                        {
                            type: 'max',
                            valueDim: 'highest',
                            symbol: 'circle',
                            symbolSize: 10,
                            label: {
                                normal: {show: false},
                                emphasis: {show: false}
                            }
                        }
                    ],
                    {
                        name: 'min line on close',
                        type: 'min',
                        valueDim: 'close'
                    },
                    {
                        name: 'max line on close',
                        type: 'max',
                        valueDim: 'close'
                    }
                ]
            }
        },
        {
            name: 'MA5',
            type: 'line',
            data: calculateMA(5),
            smooth: true,
            lineStyle: {
                normal: {opacity: 0.5}
            }
        },
        {
            name: 'MA10',
            type: 'line',
            data: calculateMA(10),
            smooth: true,
            lineStyle: {
                normal: {opacity: 0.5}
            }
        },
        {
            name: 'MA20',
            type: 'line',
            data: calculateMA(20),
            smooth: true,
            lineStyle: {
                normal: {opacity: 0.5}
            }
        },
        {
            name: 'MA30',
            type: 'line',
            data: calculateMA(30),
            smooth: true,
            lineStyle: {
                normal: {opacity: 0.5}
            }
        },

    ]
};

Other comments [其他信息]

第一个为空是已经报错，所以第一个k线没有消失；第5颗可以正常消失