Yep, this recently regressed for me too in git master. I kept forgetting to report it, so thanks, Dr Chapatin!

Git commit b38e157f3a0fb70e8b876089dca4cd9236a38465 by Aleix Pol.
Committed on 27/02/2018 at 13:01.
Pushed by apol into branch 'Plasma/5.12'.

Fix flatpak source filtering

Can't filter by display name, should filter by id.

M  +1    -1    discover/qml/SourcesPage.qml

https://commits.kde.org/discover/b38e157f3a0fb70e8b876089dca4cd9236a38465

Not fixed, I'm afraid. The problem remains on both the Plasma Plasma/5.12 and master branches.

I cannot reproduce neither on my devel system or my neon and kubuntu systems.

Could you maybe try to dig a little bit?

This patch could help:

diff --git a/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp b/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp
index 3d071e0b..30072b91 100644
--- a/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp
+++ b/libdiscover/backends/FlatpakBackend/FlatpakBackend.cpp
@@ -1105,6 +1105,8 @@ ResultsStream * FlatpakBackend::search(const AbstractResourcesBackend::Filters &
     }
     auto f = [this](AbstractResource* l, AbstractResource* r) { return flatpakResourceLessThan(l,r); };
     std::sort(ret.begin(), ret.end(), f);
+
+    qWarning() << "search result" << filter << ret.size();
     return new ResultsStream(QStringLiteral("FlatpakStream"), ret);
 }

Huh, it actually works now with the latest commits. :/

Nope, broken again. And also, now the KDE apps Flatpak repo doesn't work either. Something needs to be done to make this more robust, and maybe we should an add an autotest, too.

With that line of debugging code added, here's what's printed the the console when I try to browse to Flathub and then KDEapps:

search result Filters(extends:"org.kde.discover.desktop",) 305
search result Filters(origin:"Central repository of Flatpak applications",) 305
search result Filters(origin:"KDE Applications (nightly builds)",) 305

So it's listing by display (as it was before my patch) instead of sourceId...

Really weird :/

Git commit b15639cbba4b285301dd0359bfbd9725165eeab1 by Aleix Pol.
Committed on 16/03/2018 at 11:12.
Pushed by apol into branch 'Plasma/5.12'.

Include a test that makes sure we can list origins

M  +8    -0    libdiscover/backends/FlatpakBackend/tests/FlatpakTest.cpp

https://commits.kde.org/discover/b15639cbba4b285301dd0359bfbd9725165eeab1

Can somebody please provide some more information on how to reproduce this?

I'm not able to reproduce this anymore as of https://cgit.kde.org/discover.git/commit/?h=Plasma/5.12&id=e546dcc591cccf3fbc61d9344a78c63fe1b82a18