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DetectorImpl uses EnvStore to decide if this detector should be added with hierarchical attributes so 2) can be achieved.

Naming

In general xtcdata/xtc/ShapesData.hh::Name names should be python compatible containing only A-Z,a-z,0-9,_.  An exception is that  Unfortunately there are several exceptions that make general naming conventions difficult to enforce in xtcdata/xtc/ShapesData.hh::Name:

• ENUMDICT and ENUMVAL types have special handling that requires a ":".
• Attributes (e.g. attr1, attr2 in evt._dgrams[nDgram].detname[nSegment].drpClassName.attr1.attr2...) are created by adding "." in the names.

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• I think if

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• no alias is specified for epics variables then the ugly epics name is used

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• (often having ":", ".", maybe others, but I haven't seen any)
  • feels like we should prevent "." in the xtc name for epics vars, given the fatal error below where "." is incorrectly interpreted as an attribute delimeter
• in the case of step-scans I think the epics variables have no python-compatible alias name.

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• Need to avoid "." here too?

The one "fatal" case I have seen is if an epics name has a "." in it which is interpreted as an attribute delimiter.  This gives rise to this error:

(ps-4.1.3) psanagpu102:~$ detnames exp=tmoc00118,run=232
Traceback (most recent call last):
  File "/cds/home/c/cpo/git/lcls2/install/bin/detnames", line 11, in <module>
    load_entry_point('psana', 'console_scripts', 'detnames')()
  File "/cds/home/c/cpo/git/lcls2/psana/psana/app/detnames.py", line 71, in detnames
    names = myrun.detinfo.keys()
  File "/cds/home/c/cpo/git/lcls2/psana/psana/psexp/run.py", line 159, in detinfo
    info[(detname,det_xface_name)] = _enumerate_attrs(getattr(self.Detector(detname),det_xface_name))
  File "/cds/home/c/cpo/git/lcls2/psana/psana/psexp/run.py", line 118, in Detector
    setattr(det,drp_class_name,drp_class(det_name, drp_class_name, self.dsparms.configinfo_dict[det_name], self.dsparms.calibconst[det_name], env_store, var_name))
  File "/cds/home/c/cpo/git/lcls2/psana/psana/detector/misc_detectors.py", line 23, in __init__
    values = getattr(names,n).split('\n')
AttributeError: 'container.Container' object has no attribute 'split'
(ps-4.1.3) psanagpu102:~$ 

Proposal: all pvnames should have "." replaced with "_" in ShapesData.hh::Name.  This should be done by the step-scan software and epicsArch. PvaDetector doesn't need it because it already has to provide an xtc-compatible name, I think.

Can we provide any xtc-level naming enforcement?  Feels non-trivial, since we have to allow ":" (for epics step-scans) and "." for attribute hierarchies.