message: fix(core): remove convention route assert for base check
diff: import { winPath } from '@umijs/utils';
  -import assert from 'assert';
  import { existsSync, lstatSync, readdirSync, statSync } from 'fs';
  import { extname, relative, resolve } from 'path';
  import { defineRoutes } from './defineRoutes';
  @@ -17,10 +16,9 @@ export function getConventionRoutes(opts: {
  exclude?: RegExp[];
  }) {
  const files: { [routeId: string]: string } = {};
  - assert(
  - existsSync(opts.base) && statSync(opts.base).isDirectory(),
  - `Convention routes base not found.`,
  - );
  + if (!(existsSync(opts.base) && statSync(opts.base).isDirectory())) {
  + return {};
  + }
  visitFiles({
  dir: opts.base,
  visitor: (file) => {
  