The embedding machinery ignores user_ns

[g2p]

Quick demonstration:

from IPython import embed

user_ns = dict(cookie='monster')
embed(user_ns=user_ns, banner1='Please type: cookie')

Bisecting shows the last good revision was 5397fc8, the following revisions don't have working embedding until 9a2ec9f, which has embedding but lost user_ns functionality.
I don't know how to write automated tests for embedding (can stdin be hijacked?).
Paging @takluyver.

[takluyver]

I think I see the issue. user_ns when we create the shell is overridden by local_ns when we activate it. I'll think about the best way to resolve it.

[fperez]

This looks pretty serious, I really would hate for 0.12 to come out with broken embedding, seeing as it will be the ubuntu LTS ipython...

[takluyver]

Right, there are four possibilities for each of user_ns and user_module when embedding:

1. Not specified at instantiation or activation - use the auto-detected namespace/module at activation
2. Specified at instantiation only - use that, and do not auto-detect (this is what we're getting wrong)
3. Specified at activation only - use that, don't auto-detect
4. Specified at instantiation and activation - what's specified at activation overrides what's specified at instantiation.

I've got an idea how to resolve this. I'll put together a PR, hopefully this evening.

[fperez]

Funny coincidence: #136 and this (#1136) are both on scoping problems with the embedding code :)

[takluyver]

Have a look at PR #1140.

[takluyver]

Merged PR #1140, which resolves this.