fix(issue-688): 当 marker symbol 没有内置时，method 为空，导致 crash

packages/g-canvas/src/shape/marker.ts

@@ -85,12 +85,13 @@ class Marker extends ShapeBase {
     } else {
       // 内置 symbol 的 path 都是绝对路径，直接绘制即可，不需要对 path 进行特殊处理
       method = Marker.Symbols[symbol];
-      path = method(x, y, r);
-    }
 
-    if (!method) {
-      console.warn(`${symbol} marker is not supported.`);
-      return null;
+      if (!method) {
+        console.warn(`${symbol} marker is not supported.`);
+        return null;
+      }
+
+      path = method(x, y, r);
     }
 
     return path;

packages/g-canvas/src/util/draw.ts

@@ -140,6 +140,9 @@ function checkElementRefresh(shape: IElement, region: Region): boolean {
 // 绘制 path
 export function drawPath(shape, context, attrs, arcParamsCache) {
   const { path, startArrow, endArrow } = attrs;
+  if (!path) {
+    return;
+  }
   let currentPoint = [0, 0]; // 当前图形
   let startMovePoint = [0, 0]; // 开始 M 的点，可能会有多个
   let distance = {

packages/g-canvas/tests/bugs/issue-688-spec.js

@@ -0,0 +1,49 @@
+const expect = require('chai').expect;
+import { Canvas } from '../../src';
+const container = document.createElement('canvas');
+container.width = 300;
+container.height = 300;
+container.id = 'marker';
+document.body.appendChild(container);
+
+describe('#688', () => {
+  const canvas = new Canvas({
+    container,
+    width: 600,
+    height: 500,
+  });
+
+  canvas.addGroup();
+
+  const commonAttrs = {
+    r: 30,
+    lineWidth: 2,
+    stroke: '#F04864',
+    fill: '#1890FF',
+  };
+  const crossMarker = canvas.addShape('marker', {
+    attrs: {
+      ...commonAttrs,
+      x: 100,
+      y: 100,
+      symbol: 'cross',
+    },
+  });
+
+  // 被影响了
+  const circleMarker = canvas.addShape('marker', {
+    attrs: {
+      ...commonAttrs,
+      x: 300,
+      y: 100,
+      symbol: 'circle',
+    },
+  });
+
+  it('init', () => {
+    expect(crossMarker.attr('symbol')).eqls('cross');
+    expect(crossMarker.attr('path')).eqls(undefined);
+    expect(circleMarker.attr('symbol')).eqls('circle');
+    expect(circleMarker.attr('path')).not.eqls(null);
+  });
+});