Edits not being stored in user_actions table

Dev
6

I just realized that either I don’t fully understand the cases where an edit notification is created or this is a much more widespread problem than I thought.

Main assumptions

If User A edits what User B wrote, several things happen:

  • A new row gets added to the post_revisions table.
  • A new row gets added to the user_actions table with action_type = 11.
  • By going to /u/userB/notifications/edits, User B will be able to see that a new edit was made by User A (this depends on user_actions).
  • By clicking on the pencil icon in his post, User B will be able to see the actual edit that User A performed (this depends on post_revisions).

Test

If the above assumptions are correct, this query should show all the rows in the post_revisions table for posts created by User B (in this case, id 259) that were edited by any user (other than himself, or the system user), along with the corresponding rows in user_actions for action_type = 11.

with my_user_posts as (
  select
    p.id,
    p.user_id
  from
    posts p
  where
    p.user_id = 259 -- choose a user id
)
select
  up.user_id as my_user_id,
  ua.user_id as target_user_id,
  pr.post_id,
  ua.target_post_id,
  pr.user_id as editor_user_id,
  ua.acting_user_id,
  ua.action_type,
  pr.created_at as edit_created_at,
  ua.created_at as action_created_at
from
  post_revisions pr
  inner join my_user_posts up on up.id = pr.post_id
  and up.user_id != pr.user_id -- no self edits
  and pr.user_id != -1 -- no system edits
  left join user_actions ua on ua.target_post_id = pr.post_id
  and ua.action_type = 11 -- only EDIT actions
order by
  pr.post_id,
  pr.created_at;

Expected output

Every row has both post_revisions data along with user_actions data.

Actual output

Some of the post_revisions rows doesn’t have matching user_actions data. Therefore, the user can see the revisions by clicking on the pencil in each post, but wasn’t notified about receiving several edits.

image
image1785×252 19.4 KB

Things I’ve tried

  • Adding an additional edit to an old post without user_action data. Result: the user_action data also did not appear.
  • Creating a fake user, copying the pre-edit content of a post without user_action data, creating a post with it and applying the same edit that was done with a different user. Result: the user_action data appeared correctly.
  • Repeating the above procedures when the user is active or offline. Result: no change.
  • Repeating the above procedures changing the editing grace period. Result: no change.

Conclusions

  • The issue doesn’t appear to be:

    • user-specific. It happens to practically every user.
    • connection-specific. The fact that the user is active or offline doesn’t change the output.
    • time-specific. Changing the editing grace period had no effect.

  • The issue appears to be

    • action-specific. I have not seen any issues notifying any of the other actions (LIKE, WAS_LIKED, RESPONSE, REPLY, MENTION or QUOTE). The only problem is with EDIT actions.

    • post-specific. It doesn’t happen to every post, only specific ones (seemingly at random)

  • One possibility is that something is happening during the creation of specific posts to prevent EDIT user_actions from being saved, but I have no idea what this could be.

  • It’s also possible that this is happening by design and that there are specific conditions under which users are not notified of edits, but I haven’t seen this documented anywhere.

Next steps

  • If you know a reason why edit notifications might not get triggered every time there is an edit, please let me know.
  • If you have your own Discourse instance, could you run the above SQL query on some of your user ids to see if you also see missing user_actions data and report back?
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