TypeError in ScalerCH.select_channels(None)

[prjemian]

Seems that the code committed as part of #692 did not make it into tag 1.3.2, thus my local code expecting this fix fails like this:

~/.ipython/profile_bluesky/startup/20-detectors.py in <module>()
      4 
      5 scaler = ScalerCH('vm7:scaler1', name='scaler')
----> 6 scaler.select_channels(None)
      7 

~/Apps/anaconda/envs/bluesky/lib/python3.6/site-packages/ophyd/scaler.py in select_channels(self, chan_names)
    136 
    137         read_attrs = ['chan01']  # always include time
--> 138         for ch in chan_names:
    139             try:
    140                 read_attrs.append(name_map[ch])

TypeError: 'NoneType' object is not iterable

The fix does exist in the master branch now. Can a new tag be made in the next week?

[prjemian]

Example local workaround until the new tag.

[danielballan]

Thanks for sharing the workaround. We could at least tag a beta this week. @klauer Are there still known problems with signals / callback-processing in master that should give us pause before tagging a new stable release?

[klauer]

Yes, this needs resolving: #708

We're looking to a new pyepics release soon, but there is not yet a fix designed for this issue. It likely will cause issues with PV reusage during a session. As far as I am aware, the refactor has not been extensively tested outside of CI.

[tacaswell]

Ah, when I did the backports I looked at merged PRs, it looks like that commit got pushed directly to master so I missed it.

As @klauer points out master currently needs a bit more work before it can be tagged (and has some pretty big improvements (but given the rules of un-intended consequences means will also break something 😞 ) ).

Unless someone protests I'll cherry-pick that commit back to 1.3.x and tag 1.3.3 this afternoon?

[mrakitin]

That's a good plan, @tacaswell.

[danielballan]

Done and released on PyPI. Conda packages in progress.

[prjemian]

Thanks! Conda package coming or I switch to pip on this as proof-of-fix?

[prjemian]

I'm blind.

[mrakitin]

New conda packages are available at https://anaconda.org/lightsource2-tag/ophyd/files.