500 internal server error when clicking into an article

[MrOrz]

Visit: https://cofacts.g0v.tw/article/AWEET-BFyCdS-nWhunGr

TypeError: Cannot read property 'set' of null
    at /srv/www/.next/dist/ducks/articleDetail.js:182:35
    at /srv/www/node_modules/immutable/dist/immutable.js:3016:46
    at List.__iterate (/srv/www/node_modules/immutable/dist/immutable.js:2206:13)
    at IndexedIterable.mappedSequence.__iterateUncached (/srv/www/node_modules/immutable/dist/immutable.js:3015:23)
    at seqIterate (/srv/www/node_modules/immutable/dist/immutable.js:604:16)
    at IndexedIterable.IndexedSeq.__iterate (/srv/www/node_modules/immutable/dist/immutable.js:320:14)
    at IndexedIterable.toArray (/srv/www/node_modules/immutable/dist/immutable.js:4258:23)
    at List [as constructor] (/srv/www/node_modules/immutable/dist/immutable.js:2065:62)
    at reify (/srv/www/node_modules/immutable/dist/immutable.js:3570:37)
    at List.map (/srv/www/node_modules/immutable/dist/immutable.js:4401:14)

L172 - 197

return state.withMutations(function (s) {
    return s.updateIn(['data', 'article'], function (article) {
      return (article || (0, _immutable.Map)()).merge(payload.remove('replyConnections').remove('relatedArticles'));
    }).setIn(['data', 'replyConnections'], payload.get('replyConnections')).updateIn(['data', 'relatedArticles'], function (articles) {
      return !relatedArticleEdges.size ? articles : relatedArticleEdges.map(function (edge) {
        return edge.get('node').remove('replyConnections');
      });
    }).updateIn(['data', 'relatedReplies'], function (replies) {
      return !relatedArticleEdges.size ? replies : relatedArticleEdges.flatMap(function (edge) {
        return edge.getIn(['node', 'replyConnections']).map(function (conn) {
          return conn.get('reply').set('article', edge.get('node').remove('replyConnections'));
        }).filter(function (reply) {
          // Filter-out replies that is already re-used.
          return reply && !replyIds.contains(reply.get('id'));
        });
      })
      // De-duping replies using replyId, taking the reply with more relavant article
      // (which should come first)
      //
      .groupBy(function (reply) {
        return reply.get('id');
      }).map(function (replyGroup) {
        return replyGroup.first();
      }).toList();
    });
  });

L182: return conn.get('reply').set('article', edge.get('node').remove('replyConnections'));

[MrOrz]

Cause: When invoking CreateReplyConnection, it does not check if the given replyId exists.

It is recovered by manually removing the replyConnection and the replyConnectionId from the affected articles (5480022804100-rumor).

When implementing CreateReplyConnection we should check if the reply exists in the future.