fix(base): Handle nullptr args in FairRun::SetSink()

Author: dennisklein

fairroot/base/steer/FairRun.cxx

@@ -191,14 +191,11 @@ void FairRun::SetSink(std::unique_ptr<FairSink> newsink)
 {
     fSink = std::move(newsink);
     fRootManager->fSink = maybe_owning_ptr<FairSink>{fSink.get(), non_owning};
-    fUserOutputFileName = fSink->GetFileName();
-}
-
-void FairRun::SetSink(FairSink* tempSink)
-{
-    fSink.reset(tempSink);
-    fRootManager->fSink = maybe_owning_ptr<FairSink>{fSink.get(), non_owning};
-    fUserOutputFileName = fSink->GetFileName();
+    if (fSink) {
+        fUserOutputFileName = fSink->GetFileName();
+    } else {
+        fUserOutputFileName.Clear();
+    }
 }
 
 void FairRun::SetOutputFile(const char* fname)

fairroot/base/steer/FairRun.h

@@ -87,7 +87,7 @@ class FairRun : public TNamed
      * Set the sink
      */
     void SetSink(std::unique_ptr<FairSink> newsink);
-    void SetSink(FairSink* tempSink);
+    void SetSink(FairSink* newsink) { SetSink(std::unique_ptr<FairSink>{newsink}); }
     /**
      * return a non-owning pointer to the sink
      */