Hi,
I ran into the following problem recently: I conducted a session and afterwards, could not download the merged all_apps_wide files. Downloading the datasets for each app works fine.
This is the error message:
„AssertionError: Session itund9of has 300 participants, but round 1 of app 'pol_scale_extro' has 299 players. The number of players in the subsession should always match the number of players in the session. Please report this issue and then reset the database."
I started the session for 300 paritcipants. The datasets for the first three apps have 300 lines each but the fourth one is missing one line. Apparently, Player 117 goes missing in that app, leading to a mismatch between Player and id_in_group. A total of 80 subjects participated in the session, so there has never been a Player 117.
I've never heard of this issue. Does anybody have any idea how this might happen and how to avoid it? If you need more information, please let me know.
Cheers
Dirk

I had a similar error message recently: 

Session vg0saqyh has 4 participants, but round 1 of app 'workers_part2' has 0 players. The number of players in the subsession should always match the number of players in the session. Please report this issue and then reset the database.

I have also never heard of that issue before. It seems like this problem happens more often than I thought...

Hi Daniel,
so when you download the datafile for 'workers_part2', it is completely empty, while all other apps have four lines?
Some additional information on my case:
- I program using oTree Studio (classical), the server runs on oTree 6.0.3 (nano requirements: otree>=6.0.3, psycopg2>=2.8.4, sentry-sdk>=0.7.9)
- The code worked perfectly fine before
- The code works perfectly fine on a different server
- Before running the session, I deleted two sessions instead of archiving them (which I usually do not do). Before that, I had no issues downloading the all_apps_wide file
I have left the session open for now, so if anybody needs me to play around with it some more, let me know.
Best
Dirk

Hi, I recommend loading your project into OTAI (save it to your assets and ask OTAI to recreate it). The OTAI / on.otree.org hosting is more robust against these types of issues.

In any case, you should upgrade to the latest oTree 6.0.14 which fixes a security vulnerability.

Hi Chris,
first, thanks (again) for your help! I really appreciate that you're so active in the forum.
Two questions:
1. As far as I know, our server (dedicated oTree server set up by my university's IT) has already been updated to work with oTree 6.0.15. Should we use .14 over .15? And are the other packages (psycopg2>=2.8.4, sentry-sdk>=0.7.9) OK or do we need to update these, as well?
2. I do not think that this is an issue with my code but I will definitely take a look at OTAI for more complex future projects.
Best
Dirk