Ubuntu Unity Hack tries to run on a non Ubuntu distro without Unity

Before posting

Please follow the steps below and check the boxes with [x] once you did the step.

[X] I checked the issue tracker for similar issues
[X] I DIDN'T check the changelog but I built master
[X] I DIDN'T try the latest Clementine build from here but I built master

System information

Please provide information about your system and the version of Clementine used.

Operating System: openSUSE Tumbleweed, x86_64
Clementine version: clementine built from commit dfeb1182f97cf8fc2625523d9a6166a9e20f7e96

Expected behaviour / actual behaviour

Expected: Ubuntu unity hack does not run
Actual: Ubuntu unity hack runs while Unity is not installed

I noticed this by running Clementine in Valgrind and seeing:

==22600== Syscall param waitid(infop) points to unaddressable byte(s)
==22600==    at 0x78B3A8D: syscall (in /usr/lib64/libc.so.6)
==22600==    by 0x5107536: ??? (in /usr/lib64/libQt5Core.so.5.15.7)
==22600==    by 0x50EADFD: ??? (in /usr/lib64/libQt5Core.so.5.15.7)
==22600==    by 0xD70533: UbuntuUnityHack::UbuntuUnityHack(QObject*) (ubuntuunityhack.cpp:47)
==22600==    by 0xA68306: main (main.cpp:448)
==22600==  Address 0x0 is not stack'd, malloc'd or (recently) free'd

Steps to reproduce the problem (only for bugs)

run Clementine (in Valgrind) on a distribution that does not run Unity and does not have an /etc/lsb-release file

Suggested solution

ubuntuunityhack.cpp tries to know whether we are on Ubuntu. If so, it proceeds to apply its workaround.

The check is as follows: it checks if there is a /etc/lsb release file. If so, and if DISTRIB_ID=Ubuntu is not found, it returns. A probably better way to do it would be to return if /etc/lsb-release file is not found, because Ubuntu should have it.

This can be done by changing:

  // Check if we're on Ubuntu first.
  QFile lsb_release("/etc/lsb-release");
  if (lsb_release.open(QIODevice::ReadOnly)) {
    QByteArray data = lsb_release.readAll();
    if (!data.contains("DISTRIB_ID=Ubuntu")) {
      // It's not Ubuntu - don't do anything.
      return;
    }
  }

to:

  // Check if we're on Ubuntu first.
  QFile lsb_release("/etc/lsb-release");
  if (!lsb_release.open(QIODevice::ReadOnly) || !lsb_release.readAll().contains("DISTRIB_ID=Ubuntu")) {
    // It's not Ubuntu - don't do anything.
    return;
  }

Even better, Clementine could check that Unity is running. Unity could theoretically be running from a distro that's not Ubuntu. I don't have Unity, so I won't be able to contribute a patch that does this.

It is to be noted that after preventing the ubuntu unity hack from running, I see:

==22990== Syscall param waitid(infop) points to unaddressable byte(s)
==22990==    at 0x78B3A8D: syscall (in /usr/lib64/libc.so.6)
==22990==    by 0x5107536: ??? (in /usr/lib64/libQt5Core.so.5.15.7)
==22990==    by 0x50EADFD: ??? (in /usr/lib64/libQt5Core.so.5.15.7)
==22990==    by 0xAD50A8: WorkerPool<AbstractMessageHandler<cpb::tagreader::Message> >::StartOneWorker(WorkerPool<AbstractMessageHandler<cpb::tagreader::Message> >::Worker*) (workerpool.h:296)
==22990==    by 0xAD44EB: WorkerPool<AbstractMessageHandler<cpb::tagreader::Message> >::DoStart() (workerpool.h:252)
==22990==    by 0x1047B2A: _WorkerPoolBase::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (moc_workerpool.cpp:92)
==22990==    by 0x519FC3F: QObject::event(QEvent*) (in /usr/lib64/libQt5Core.so.5.15.7)
==22990==    by 0x66663FD: QApplicationPrivate::notify_helper(QObject*, QEvent*) (in /usr/lib64/libQt5Widgets.so.5.15.7)
==22990==    by 0x5174127: QCoreApplication::notifyInternal2(QObject*, QEvent*) (in /usr/lib64/libQt5Core.so.5.15.7)
==22990==    by 0x51770C0: QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) (in /usr/lib64/libQt5Core.so.5.15.7)
==22990==    by 0x51CC352: ??? (in /usr/lib64/libQt5Core.so.5.15.7)
==22990==    by 0x5DC2A8F: g_main_context_dispatch (in /usr/lib64/libglib-2.0.so.0.7400.1)
==22990==  Address 0x0 is not stack'd, malloc'd or (recently) free'd

So the cause of this message is probably elsewhere

clementine-player / Clementine