Ticket #4530: fix_doctest_underscore_problem.diff

_doctest.py

@@ -1239 +1239 @@
             # __patched_linecache_getlines).
             filename = '<doctest %s[%d]>' % (test.name, examplenum)
 
+            # The exec statement with 'single' mode of compilation
+            # overwrites the _ builtin.  Store the original value so
+            # that you can restore it later.
+            original_underscore = __builtins__['_']
+
             # Run the example in the given context (globs), and record
             # any exception that gets raised.  (But don't intercept
             # keyboard interrupts.)
@@ -1249 +1254 @@
                 self.debugger.set_continue() # ==== Example Finished ====
                 exception = None
             except KeyboardInterrupt:
+                __builtins__['_'] = original_underscore
                 raise
             except:
                 exception = sys.exc_info()
                 self.debugger.set_continue() # ==== Example Finished ====
 
+            __builtins__['_'] = original_underscore
+
             got = self._fakeout.getvalue()  # the actual output
             self._fakeout.truncate(0)
             outcome = FAILURE   # guilty until proved innocent or insane