python - Segmentation fault: 11 in OS X

Question

I am getting an issue in Python 3.3.2 on OSX 10.9 where if I open Python in a terminal window, it exits with "Segmentation error: 11" after the second line I enter, regardless of what the two commands are. For example, if I enter:

>>> for x in range(1000): print(x)

that works fine, but if I enter:

>>> for x in range(1000):
...     print(x)

then I get the error when I press enter on the second line. I can also run a script with more than 2 lines without any problems.

I updated to OSX 10.9 this afternoon, so I suspect that may be it.

However, I just recently installed IPython (along with several other packages) and have been using that the past couple of days, so it could be something else I installed recently. I had a couple unsuccessful attempts at installing PyQt where I ran configure.py but then the "make" command failed, which I was also suspicious of.

I tried reinstalling Python, but it didn't resolve the issue. Both IPython and IDLE work with no problems. I'm just concerned about what could be the underlying issue.

Answer 1

This is a bug in the readline compatibility in python, related to changes introduced in OSX10.9. This weekend, release candidates for Python2.7.6 and Python3.3.3 were released which fix this bug. The download links are below.

http://python.org/download/releases/2.7.6/

http://python.org/download/releases/3.3.3/

Here's the issue, quoting from Ned Deily, writing on the python-dev email list.

On Tuesday, Apple released OS X 10.9 (a.k.a. Mavericks). There has already been a lot of interest in it, in part because Apple has made it available for free and has made it easy for users with 10.8, 10.7, and (most) 10.6 systems to upgrade directly to 10.9. Unfortunately, there are issues with our current maintenance releases (3.3.2 and 2.7.5) on OS X 10.9 that call for new maintenance releases as soon as possible.

One is critical in that it causes the interpreter to crash when running in interactive mode (http://bugs.python.org/issue18458). The problem was due to a long-standing compatibility issue in libedit's readline compatibility layer that upstream has finally fixed and Apple has now shipped in 10.9. Because the python.org installers dynamically link to libedit, the original workaround in readline.c for the original design flaw in history indexing now causes a segfault on 10.9 when the user types in the second command interactively. Not good. Ronald devised a fix that allows readline.so at runtime to detect and work with either version of libedit so that we continue to have binary compatibility across multiple OS X releases. That fix is already out in the 3.4.0 alphas and backported to the 3.3 and 2.7 branches, awaiting release there. Just in the last 12 hours, there have been at least four duplicates of the issue reported by users. I've updated the original issue to explicitly mention 10.9, now that it is no longer under NDA, and to provide a downloadable script for inexperienced users to workaround the problem by "removing" readline.so. Presumably, as word gets out, there will be fewer duplicate issues opened but the impact will remain.