title: How to investigate " Attempt to free unreferenced scalar"
body: <p>A Perl script (which uses a load of locally-written modules, and is under active development) has just started producing sporadic</p>
  
  <p>" Attempt to free unreferenced scalar: SV 0xa6e685c, Perl interpreter: 
  0x96d9008 during global destruction." </p>
  
  <p>messages. This are always repeatable, in the sense that a particular sequence of commands always produces the message if it ever does, but I've not managed to isolate a simple or stand-alone case which elicits it. In particular, I haven't yet seen it when running the script from the Perl debugger (I can get it when debugging a script which uses IPC::Open3 to run my target script.)</p>
  
  <p>I realise that this is just possibly a bug in Perl, but much more likely to be something I'm doing, very likely round my calls to SVN::Client; but I'm stumped for a way to investigate it, and I wondered if anybody had any pointers. </p>
  
  <p>Perl 5.10.0; Various versions of Fedora Linux. I'm going to try it on Perl 5.12, but unless it manifests there too, it won't really help me. 
  <strong>Edit</strong>: a particular case which reliably gives the message in 5.10 doesn't in 5.12. Unfortunately that doesn't really tell me anything.</p>