fix for list pdb listcommand, broken for %run -d

when calling %run -d the filename available for pdb is <string> which is
not a proper filename. %run now adds a _exec_lines attribute containing the
correct filename.

IPython/core/debugger.py

@@ -441,11 +441,17 b' class Pdb(OldPdb):'
             tpl_line = '%%s%s%%s %s%%s' % (Colors.lineno, ColorsNormal)
             tpl_line_em = '%%s%s%%s %s%%s%s' % (Colors.linenoEm, Colors.line, ColorsNormal)
             src = []
+            if filename == "<string>" and hasattr(self, "_exec_filename"):
+                lines = list(open(self._exec_filename))
+            else:
             lines = linecache.getlines(filename)
             try:
                 encoding, _ = openpy.detect_encoding(_readline(lines))
             except SyntaxError:
                 encoding = "ascii"
+            if not lines:
+                print >>io.stdout, "No src could be located using filename: %r"%filename
+                return #Bailing out, there is nothing to see here
             for lineno in range(first, last+1):
                 line = py3compat.cast_unicode(lines[lineno])
                 if not line:

IPython/core/magics/execution.py

@@ -554,6 +554,8 b' python-profiler package from non-free.""")'
                         print "%s prompt to start your script." % deb.prompt
                         ns = {'execfile': py3compat.execfile, 'prog_ns': prog_ns}
                         try:
+                            #save filename so it can be used by methods on the deb object
+                            deb._exec_filename = filename
                             deb.run('execfile("%s", prog_ns)' % filename, ns)
 
                         except: