Allow for media cover deletion

[trinity-1686a]

Fix #356

[igalic]

sssiiiighqlite 🙀

[elegaanz]

Maybe this change should be integrated in the migrations that introduced constraints, because when you run migrations on an instance with illustrated articles, you get this error:

Running migration 2018-12-08-175515_constraints
update or delete on table "medias" violates foreign key constraint "posts_cover_id_fkey" on table "posts"

(After seeing this error on baptiste.gelez.xyz I tried to manually fix it, but it just ended in an instance reset 😬)

(I don't think it is a good idea to change previous migrations, but we don't really have choice…)

[trinity-1686a]

@BaptisteGelez I don't understand, what error did you run into? Is it when an article from before 2018-12-08-175515_constraints reference a no longer existing media?

[elegaanz]

It seem to happen when a media is used both as avatar and post cover. This query deletes it: https://github.com/Plume-org/Plume/blob/master/migrations/postgres/2018-12-08-175515_constraints/up.sql#L51 but it fails because it is used on a post.

Edit: actually, the media doesn't need to be used as avatar. If it owned by a duplicate user, the query will fail.

Edit 2: the user doesn't even need to be duplicated. For instance, some user have an empty followers_endpoint property, because they were created at a time this property didn't exist.

[codecov]

Codecov Report

Merging #387 into master will increase coverage by 1.42%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #387      +/-   ##
==========================================
+ Coverage   27.86%   29.29%   +1.42%     
==========================================
  Files          63       63              
  Lines        6280     7671    +1391     
==========================================
+ Hits         1750     2247     +497     
- Misses       4530     5424     +894

[elegaanz]

Travis is happy, I think we can safely merge that. Thanks!

[agateblue]

I'm facing the same issue described by @BaptisteGelez while applying this migration, and I cannot afford to reset my instance. Is there anything to do to manually fix the issue? I can run SQL by hand if needed :)

[elegaanz]

@EliotBerriot try to find user with empty followers_endpoint with SELECT id, username FROM users WHERE followers_endpoint = ''; and if anything is returned, edit the follower endpoint so that it has a value (it can be anything as long as it is not null, nor already used by another user). If I remember correctly, that's how I fixed it on fediverse.blog. Sorry for the bug… 😕

If it still doesn't work, try to check users.ap_url, user.inbox_url and user.outbox_url too.

[agateblue]

@BaptisteGelez SELECT id, username FROM users WHERE followers_endpoint = ''; returned a bunch of users, and I updated it w ith UPDATE users SET followers_endpoint='noop' WHERE followers_endpoint = '';`

This is the current returns for all the attributes you mentions:

plume=# SELECT id, username FROM users WHERE ap_url = '';
 id | username 
----+----------
(0 rows)

plume=# SELECT id, username FROM users WHERE inbox_url = '';
 id | username 
----+----------
(0 rows)

plume=# SELECT id, username FROM users WHERE outbox_url = '';
 id | username 
----+----------
(0 rows)

plume=# SELECT id, username FROM users WHERE followers_endpoint = '';
 id | username 
----+----------
(0 rows)

Unfortunately, applying the migrations return the same error again:

eliotberriot@peeters:/srv/Plume$ docker-compose run --rm plume diesel migration run --migration-dir migrations/postgres/
Starting plume_postgres_1 ... done
Running migration 2018-12-08-175515_constraints
update or delete on table "medias" violates foreign key constraint "posts_cover_id_fkey" on table "posts"

The issues seems to lie within the medias/posts relation, so I'm not sure what it has to do with users?

Anyway, don't be sorry for this: I know the software was still in development and I could face this kind of bug, that was part of the deal :)

[elegaanz]

Okay, so maybe try to reset the post covers (it will not impact your articles as you didn't used them for Funkwhale's blog), with UPDATE posts SET cover_id = null;. I don't know if it will fix the issue, but it is worth a try.

[agateblue]

@BaptisteGelez at least with the cover_id thing I get another error:

eliotberriot@peeters:/srv/Plume$ docker-compose run --rm plume diesel migration run --migration-dir migrations/postgres/
Starting plume_postgres_1 ... done
Running migration 2018-12-08-175515_constraints
update or delete on table "comments" violates foreign key constraint "comments_in_response_to_id_fkey" on table "comments"

The issues is withing the comments_in_response_to_id_fkey constraint now

[elegaanz]

I made this script that should delete comments with invalid ActivityPub URLs, and their replies.

CREATE OR REPLACE FUNCTION delete_comment (id int) RETURNS comments
AS $$
DECLARE
  r int;
BEGIN
  FOR r IN (SELECT id FROM comments WHERE in_response_to_id = id) LOOP
    SELECT delete_comment(r);
  END LOOP;
  DELETE FROM comments WHERE id = id;
END $$ LANGUAGE plpgsql;

SELECT delete_comment(id) FROM comments WHERE ap_url = '';

I didn't tested it, but it should only delete broken comments (and hopefully fix the migrations).

[agateblue]

@BaptisteGelez unfortunately, this doesn't fix it (for me):

eliotberriot@peeters:/srv/Plume$ docker-compose exec postgres psql -U plume
psql (10.5 (Debian 10.5-2.pgdg90+1))
Type "help" for help.

plume=# 
plume=# 
plume=# CREATE OR REPLACE FUNCTION delete_comment (id int) RETURNS comments
plume-# AS $$
plume$# DECLARE
plume$#   r int;
plume$# BEGIN
plume$#   FOR r IN (SELECT id FROM comments WHERE in_response_to_id = id) LOOP
plume$#     SELECT delete_comment(r);
plume$#   END LOOP;
plume$#   DELETE FROM comments WHERE id = id;
plume$# END $$ LANGUAGE plpgsql;
CREATE FUNCTION
plume=# 
plume=# SELECT delete_comment(id) FROM comments WHERE ap_url = '';
 delete_comment 
----------------
(0 rows)

plume=# \q

eliotberriot@peeters:/srv/Plume$ docker-compose run --rm plume diesel migration run --migration-dir migrations/postgres/
Starting plume_postgres_1 ... done
Running migration 2018-12-08-175515_constraints
update or delete on table "comments" violates foreign key constraint "comments_in_response_to_id_fkey" on table "comments"