pyin message now have execution_count

[ivanov]

This addresses #1619.

One remaining instance of a 'pyin' message that currently lacks execution_count is found on line 112 of IPython/zmq/pykernel.py - I'm not sure when this code path is used, and what the appropriate way to proceed there is.

@minrk, I'm ping-ponging this one back at you :)

[fperez]

Looks clean to me, will also give time so others can review. Thanks!

[minrk]

Don't worry about pykernel. ~nobody uses it, and it should just be removed (I've been working on merging the Kernel implementations for Engines/Kernels, and that branch removes pykernel).

[minrk]

This looks good to me, +1 to merge.

[fperez]

Great, merging now. Thanks @ivanov !

[fperez]

Actually, I just realized we have that other codepath to deal with, @ivanov... What do you want to do about it? Do you want to have a go at fixing it there as well? We might as well leave this one clean so we can close #1619...

[minrk]

@fperez pykernel has always violated the message spec all over the place, and we should just remove it. I wouldn't bother adding this to it.

[minrk]

If you do want to fix it in pykernel: the value should just be 0 or None, because execution count is not defined for a non-IPython kernel. but my vote is to simply ignore it and merge as-is.

[fperez]

Ah, hold on; I failed to realize that the problem was in pykernel, which @minrk already said is slated for the guillotine. Let's just merge as-is. I'll do so right now, thanks everyone! (and sorry for my confusion)