It was added in 477c8d5e702 (a huge svn merge commit), with this reference:


      r45955 | georg.brandl | 2006-05-10 19:13:20 +0200 (Wed, 10 May 2006) | 4 lines

      Patch #721464: pdb.Pdb instances can now be given explicit stdin and
      stdout arguments, making it possible to redirect input and output
      for remote debugging.

I think a good alternative patch might be:

```diff
 Lib/pdb.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git i/Lib/pdb.py w/Lib/pdb.py
index f5d33c27fc..daf49b3629 100755
--- i/Lib/pdb.py
+++ w/Lib/pdb.py
@@ -141,7 +141,9 @@ def __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,
                  nosigint=False, readrc=True):
         bdb.Bdb.__init__(self, skip=skip)
         cmd.Cmd.__init__(self, completekey, stdin, stdout)
-        if stdout:
+        if stdout and stdout is not sys.stdout:
+            # stdout gets passed with do_debug for example, but should usually
+            # not disable using raw input then.
             self.use_rawinput = 0
         self.prompt = '(Pdb) '
         self.aliases = {}
```