libunity-protocol-private.so cannot be found

[Alberto Mardegan]

If your snap links (directly or indirectly, for instance via the Ubuntu.UnityWebApps QML module) to the libunity.so library, running it will fail with the following error:

    "file:///snap/amazon-webapp/x1/share/webbrowser-app/webcontainer/webapp-container.qml:21 plugin cannot be loaded for module \"Ubuntu.UnityWebApps\": Cannot load library /snap/amazon-webapp/x1/ubuntu-app-platform/usr/lib/x86_64-linux-gnu/qt5/qml/Ubuntu/UnityWebApps/libUnityWebApps.so: (libunity-protocol-private.so.0: cannot open shared object file: No such file or directory)\n"

libunity-protocol-private.so *is* present in the ubuntu-app-platform snap, but it's in a subdirectory which is not in the library path:

    /usr/lib/x86_64-linux-gnu/libunity/libunity-protocol-private.so.0

(not the "libunity" subdirectory). It looks like (info obtained with "objdump -a -x") libunity.so has this RPATH:

    RPATH /usr/lib/x86_64-linux-gnu/libunity

I'll try to see if using $ORIGIN in libunity helps; if not, we might have to play with LD_LIBRARY_PATH in the ubuntu-app-platform snap.