Disable monkeypatch to inspect.findsource(), leaving explanation.

IPython/core/ultratb.py

@@ -126,6 +126,14 b' def inspect_error():'
           'Below is the traceback from this internal error.\n')
 
 
+# N.B. This function is a monkeypatch we are currently not applying.
+# It was written some time ago, to fix an apparent Python bug with
+# codeobj.co_firstlineno . Unfortunately, we don't know under what conditions
+# the bug occurred, so we can't tell if it has been fixed. If it reappears, we
+# will apply the monkeypatch again. Also, note that findsource() is not called
+# by our code at this time - we don't know if it was when the monkeypatch was
+# written, or if the monkeypatch is needed for some other code (like a debugger).
+# For the discussion about not applying it, see gh-1229. TK, Jan 2011.
 def findsource(object):
     """Return the entire source file and starting line number for an object.
 
@@ -201,9 +209,10 b' def findsource(object):'
         return lines, lnum
     raise IOError('could not find code object')
 
+# Not applying the monkeypatch - see above the function for details. TK, Jan 2012
 # Monkeypatch inspect to apply our bugfix.  This code only works with py25
-if sys.version_info[:2] >= (2,5):
-    inspect.findsource = findsource
+#if sys.version_info[:2] >= (2,5):
+#    inspect.findsource = findsource
 
 def fix_frame_records_filenames(records):
     """Try to fix the filenames in each record from inspect.getinnerframes().