[Python-Dev] displayhook behavior in pdb (original) (raw)

Guido van Rossum guido at python.org
Wed Sep 16 17:00:04 CEST 2009

On Wed, Sep 16, 2009 at 3:48 AM, Paul Moore <p.f.moore at gmail.com> wrote:

2009/9/16 Michael Foord <fuzzyman at voidspace.org.uk>: > Georg Brandl wrote: >> >> May I have a short vote on this issue: >> >> http://bugs.python.org/issue6903 >> >> In short, pdb (since 2.6) uses a separate displayhook in order to avoid >> being reassigned (which screws up debugging apps that use as gettext). >> In that displayhook, I did not add the suppression of printing None, as >> it can be confusing to look at variables and get no output: >> >> (Pdb) foo >> 1 >> (Pdb) bar >> (Pdb) >> >> (You could argue that this is what the "p" command is for though.) >> >> Now in Python 3, where print is a function, if you call print in a loop >> (e.g. to debug a list or dictionary, as it is advertised in the pdb docs >> under the "alias" command), the output has the printed values interspersed >> with "None"s. >> >> Now, what is the lesser evil? >> >> > > IMO not showing the extraneous Nones is preferable.

I agree (although I don't use pdb, so my view shouldn't be given too much weight...)

I do use pdb a lot, and I agree that the new behavior is weird.

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