[IPython-dev] Nice segfault from package scanning...

Fernando Perez fperez.net at gmail.com
Wed Apr 25 12:05:09 EDT 2007

On 4/25/07, Ville M. Vainio <vivainio at gmail.com> wrote:
> On 4/25/07, Fernando Perez <fperez.net at gmail.com> wrote:
> > This is bad: we're quickly going to pick up a really bad rep if Ubuntu
> > users (a good chunk of the desktop linux population) get a long wait
> > and a segfault on every TAB after 'import'.  Let's see if we can
> > convince the Debian/Ubuntu maintainers to treat this as a bug and fix
> > it.
> I don't think there is much convincing - if it segfaults, it's a bug
> and fixes for it will be accepted.
> I'd recommend upgrading Ubuntu ipython to 2.8.1 once it's released,
> they'll get rid of PyColorize format2 bug as well (once it's fixed).
> It's worse than the broken import completer one because you can
> refrain from pressing tab after import (because it didn't do anything
> useful in the first place before the completer).

Ubuntu, as far as I know, has a policy of not actually changing
versions of packages.  I could be wrong, but I think they'll only take
a small patch that fixes that particular problem, not a version
upgrade.  Since the format2 bug wasn't in 0.7.3 (which is what they
ship), that one is not an issue.

> I think this is kinda "special usage" that should not be optimized
> for. The new import completer is very groovy and I'd like to have it
> on as a default.

My policy is to ensure that out of the box, ipython works well, if not
'best', across as wide a user base as possible.   NFS filesystems are
far from 'special usage' in the unix world: most medium-sized and
larger environments I've ever worked at are systematically NFS based.

There are already 'nice' features of ipython that we don't ship on by
default precisely because they degrade badly in certain cases (verbose
exceptions are one such example).  While very nice in common usage,
they have very poor behavior in not-so-corner cases, and that's very

And the package tab-completion is actually very slow even on a local
disk if you have a large system install: on my laptop (no NFS), the
ipython terminal just freezes for a good 10 seconds just because I
touched the TAB key.  That behavior is unacceptable, period.

IPython has a good reputation for stability and robustness, and we
should try hard to keep it that way.  Features that, while nice, have
very poor behavior (long delays, etc) in reasonable cases will always
be off by default.  We can then document well exactly how to tweak and
customize them for users who'd like a more fine-tuned experience and
are aware of the potential risks.



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