Tracker is errored only if all local endpoints fail

[sledgehammer999]

Closes #11691

[Chocobo1]

Sorry, always found out something after pressing the approve button :\

[Chocobo1]

The comment of how TrackerEntry::isWorking() works should be documented at trackerentry.cpp, no?

[sledgehammer999]

I don't know. I did it here to help any reader on why I seem to check only once but I say "multiple endpoints" (in the comment).

[sledgehammer999]

Ok, I resolved the issue with isWorking() in another way. Take another look.

[sledgehammer999]

@glassez @Chocobo1 please repeat your approval.
Now I changed it to use the find_if() algo.
Havign the same tracker (url+port) on different tiers is nonsensical. Furthermore, the tracker alert doesnt' allow to distinguish a tracker tier. Only a tracker url (which includes port too).

[kasper93]

@sledgehammer999 I tested build you posted in related issue and it doesn't work well. It fixes the issue described, but when a tracker returns error message, this error message is not shown, at least not always.

Looking at the code it is quite clear why this happens. I'm yet to build and debug this, but let me explain what I think happens.

Quick recap so we are on the same page, correct me if I mixed up something.

1. libtorrent creates multiple endpoints for single tracker
2. libtorrent sends tracker_error_alert in case of error on any endpoint for given tracker
3. qbt ignores this alert if any other endpoint reports to be working

Now this logic is fine, but look at the line here
https://github.com/qbittorrent/qBittorrent/blob/24cd7c3/src/base/bittorrent/torrenthandle.cpp#L1632
message is unconditionally overwritten. Even if the alert is not pass through.

I have a case, where tracker returns "unregistered torrent", but the message in qbt is blank (works fine with 4.2.0). Probably because if was overwritten, by the error on the other endpoint, which failed to connect of smth. Anyhow, I would need to debug this to tell more, but maybe you will fix it sooner :)

[ghost]

I have a case, where tracker returns "unregistered torrent", but the message in qbt is blank (works fine with 4.2.0). Probably because if was overwritten, by the error on the other endpoint, which failed to connect of smth. Anyhow, I would need to debug this to tell more, but maybe you will fix it sooner :)

I couldn't reproduce this. Local endpoints error out first..so the last message to overwrite would be the reachable one.

[kasper93]

This condition doesn't seem to be guaranteed, does it?

[ghost]

This condition doesn't seem to be guaranteed, does it?

You're right. It's not guaranteed. However you can't store multiple msgs for each endpoint and display multiple msgs. That would be unreasonable.