Cannot read properties of null (reading '_id')
TypeError: Cannot read properties of null (reading '_id')
    at HomeworkDetailHandler.onerror (/usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/server.ts:227:111)
    at handle (/usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/server.ts:320:21)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)
    at user_default (/usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/layers/user.ts:22:5)
    at /usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/layers/response.ts:10:9
    at /usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/layers/renderer.ts:77:5
    at base_default (/usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/layers/base.ts:75:5)
    at domain_default (/usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/layers/domain.ts:27:10)
    at /usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/server.ts:616:34
    at /usr/local/share/.config/yarn/global/node_modules/koa-static-cache/index.js:53:36
    at /usr/local/share/.config/yarn/global/node_modules/koa-static-cache/index.js:53:36
    at compressMiddleware (/usr/local/share/.config/yarn/global/node_modules/koa-compress/lib/index.js:56:5)
    at /usr/local/share/.config/yarn/global/node_modules/hydrooj/src/service/server.ts:572:50