COMPAT: concat of PeriodIndex

[max-sixty]

https://github.com/pydata/pandas/blob/master/pandas/tseries/period.py#L920
return Index(com._concat_compat(to_concat), name=name)
now should reference pandas.types.concat._concat_compat

I think this should probably fail - concat-ing a PeriodIndex with other index types?

[jreback]

this ultimately calls conat_datetime, yes which should handle PeriodIndex, but doesn't ATM (well it DOES because they are treated as object), so strictly speaking this works.

cc @sinhrks

[jreback]

this is something @sinhrks will handle when period is a real-dtype

[max-sixty]

Two separate issues

• A code breakage, because it's calling com._concat_compat which doesn't exist anymore
• Whether this should / does work in a conceptual sense

Not sure if you recognized the first issue here?

[jreback]

oh, that must not be tested :)

that has moved locations (though it may be aliased)