[Python-Dev] Avoiding error from repr() of recursive dictview (original) (raw)

Gregory P. Smith greg at krypto.org
Tue Jul 23 00:01:38 CEST 2013

On Mon, Jul 22, 2013 at 2:44 PM, Ben North <ben at redfrontdoor.org> wrote:

Hi,

A friend of mine, Ruadhan O'Flanagan, came across a bug which turned out to be the one noted in [http://bugs.python.org/issue18019], i.e.: >>> d={} >>> d[42]=d.viewvalues() >>> d This issue has been fixed in hg; the behaviour now is that a RuntimeError is produced for a recursive dictionary view: >>> d={} >>> d[42]=d.viewvalues() >>> d # (output line-broken:) {42: Traceback (most recent call last): File "", line 1, in RuntimeError: maximum recursion depth exceeded while getting the repr of a list Before finding this, though, I'd investigated and made a patch which produces a similar "..." output to a recursive dictionary. Reworking against current 2.7, the behaviour would be: >>> x={} >>> x[42]=x >>> x # existing behaviour for dictionaries: {42: {...}} >>> d={} >>> d[42]=d.viewvalues() >>> d # new behaviour: {42: dictvalues([...])} >>> d[43]=d.viewitems() >>> d # (output line-broken:) {42: dictvalues([..., dictitems([(42, ...), (43, ...)])]), 43: dictitems([(42, dictvalues([..., ...])), (43, ...)])} Attached is the patch, against current 2.7 branch. If there is interest in applying this, I will create a proper patch (changelog entry, fix to Lib/test/testdictviews.py, etc.).

Mailing lists are where patches go to get lost and die. :) Post it on an issue on bugs.python.org. Given that the RuntimeError fix has been released, your proposed ... behavior is arguably a new feature so I'd only expect this to make sense for consideration in 3.4, not 2.7. (if accepted at all)

-gps

Thanks, Ben.

Python-Dev mailing list Python-Dev at python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/greg%40krypto.org -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20130722/1ba4db5f/attachment.html>

More information about the Python-Dev mailing list