Add context manager to reload readline history when leaving a block.

IPython/core/interactiveshell.py

@@ -131,6 +131,23 b' class SeparateStr(Str):'
 class MultipleInstanceError(Exception):
     pass
 
+class ReadlineNoRecord(object):
+    """Context manager to execute some code, then reload readline history
+    so that interactive input to the code doesn't appear when pressing up."""
+    def __init__(self, shell):
+        self.shell = shell
+        self._nested_level = 0
+        
+    def __enter__(self):
+        self._nested_level += 1
+        
+    def __exit__(self, type, value, traceback):
+        self._nested_level -= 1
+        if self._nested_level == 0:
+            self.shell.refill_readline_hist()
+        # Returning False will cause exceptions to propagate
+        return False
+
 
 #-----------------------------------------------------------------------------
 # Main IPython class
@@ -737,6 +754,8 b' class InteractiveShell(Configurable, Magic):'
         else:
             # fallback to our internal debugger
             pm = lambda : self.InteractiveTB.debugger(force=True)
+        
+        with self.readline_no_record:
         pm()
 
     #-------------------------------------------------------------------------
@@ -1530,17 +1549,21 b' class InteractiveShell(Configurable, Magic):'
             # otherwise we end up with a monster history after a while:
             readline.set_history_length(self.history_length)
             
-            stdin_encoding = sys.stdin.encoding or "utf-8"
+            self.refill_readline_hist()
+            self.readline_no_record = ReadlineNoRecord(self)
             
+        # Configure auto-indent for all platforms
+        self.set_autoindent(self.autoindent)
+        
+    def refill_readline_hist(self):
             # Load the last 1000 lines from history
+        self.readline.clear_history()
+        stdin_encoding = sys.stdin.encoding or "utf-8"
             for _, _, cell in self.history_manager.get_tail(1000,
                                                 include_latest=True):
                 if cell.strip(): # Ignore blank lines
                     for line in cell.splitlines():
-                        readline.add_history(line.encode(stdin_encoding))
-
-        # Configure auto-indent for all platforms
-        self.set_autoindent(self.autoindent)
+                    self.readline.add_history(line.encode(stdin_encoding))
 
     def set_next_input(self, s):
         """ Sets the 'default' input string for the next command line.

IPython/core/magic.py

@@ -1600,8 +1600,9 b' Currently the magic system has the following functions:\\n"""'
         # every single object ever created.
         sys.modules[main_mod_name] = main_mod
         
-        stats = None
         try:
+            stats = None
+            with self.readline_no_record:
             if opts.has_key('p'):
                 stats = self.magic_prun('',0,opts,arg_lst,prog_ns)
             else: