Created attachment 598838 [details] simple program demonstrating the issue In Yum/DNF a custom object is overriding sys.stdout. It's only job is to encode Unicode strings sent to output (e.g. via 'print') so yum doesn't die on UnicodeError when its output is redirected to a file. I was wondering why cursor keys in pdb don't traverse the readline history as expected, it turns out assigning custom objects to sys.stdout silently disables readline. Attached is a trivial program demonstrating this.
I would consider moving to Python 3 from Python 2. This problem doesn't appear in Python 3 (note that the function is not called "raw_input", but "input"). Also the unicode handling is much better in Python 3. In the meantime, I will try to investigate this issue and come out with a solution for Python 2.
It seems that the core of the problem is in function "builtin_raw_input" in file Python/bltinmodule.c - there are 2 checks that try to find out whether stdin and stdout are tty. This in turn triggers some checks, whether type of stdout is types.FileType etc. So the only way I could think of is make UnicodeStream subclass of types.FileType. I however still can't find a way to properly redefine the methods/attributes in UnicodeStream and I keep getting "ValueError: I/O operation on closed file" no matter how I override the closed() or any other method/attribute. So no luck in this end. Looking at Python 3 way, the logic of finding out whether stdout is a tty is completely rewritten [1] and I think that Python 2 version would need significant adjustments to work this way. Maybe Dave, who understands Python's C implementation much better, might be able to answer backporting this behaviour would be sane. [1] http://hg.python.org/cpython/file/abc26b51fbfc/Python/bltinmodule.c#l1642
This bug appears to have been reported against 'rawhide' during the Fedora 19 development cycle. Changing version to '19'. (As we did not run this process for some time, it could affect also pre-Fedora 19 development cycle bugs. We are very sorry. It will help us with cleanup during Fedora 19 End Of Life. Thank you.) More information and reason for this action is here: https://fedoraproject.org/wiki/BugZappers/HouseKeeping/Fedora19
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
This message is a notice that Fedora 19 is now at end of life. Fedora has stopped maintaining and issuing updates for Fedora 19. It is Fedora's policy to close all bug reports from releases that are no longer maintained. Approximately 4 (four) weeks from now this bug will be closed as EOL if it remains open with a Fedora 'version' of '19'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 19 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete.
Fedora 19 changed to end-of-life (EOL) status on 2015-01-06. Fedora 19 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.