https://www.duolingo.com/profile/wchargin

[bug] [web] Can't load discussion for some sentences

When I click the "Discuss sentence" button, there is a console error, and nothing renders. I can progress through the remainder of the lesson normally, but the "Discuss sentence" button no-ops for the remainder of the lesson.

An example of a sentence that is not affected is sentence 10d15867cbe43e324f5557b501460f34. (Content: "Το ξέρω.")

An example of a sentence that is affected (i.e., fails to render) is sentence eca919975fe88042df6b12aebb17e76b. (Content: "Εγώ βάζω.")

The JSON data returned from their respective endpoints is different.

The error appears to be that the JSON data returned from the bad response has a comment field, but no comments subfield. Consequently, this.model.get("comment").get("comments").toJSON() resolves to (null).toJSON(), which fails. The underlying issue could be that the sentence is marked as having comments ("has_comment": true) when in fact there are no comments listed.

This bug is reproducible (100% repro rate upon page refresh; these two sentences happen to be at the start of my skill "Verbs: Present 1", lesson 6).

Let me know if you need any more information.

December 6, 2016

2 Comments


https://www.duolingo.com/profile/writchie4

I suspect this has to do with moderator actions on the affected discussions. Maybe deleting the last comment in a thread doesn't reset "has_comment" to false like it should?

Hopefully the information you've provided helps the devs track down the issue. It's been a problem for a long time (years now).

Edit: There's also a related issue where once this occurs, it continues to fail for every future sentence in the lesson.

December 6, 2016

https://www.duolingo.com/profile/wchargin

duo devs, thank you for including sourcemaps with your bundled JS files! :-)

December 6, 2016
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