Problems in @orderby

[bkamins]

@pdeffebach
Following https://discourse.julialang.org/t/how-does-orderby-work-with-multiple-columns/88155/2 investigation I found two problems with @orderby:

1. the docstring recommends using sortperm, but I do not understand your logic behind this, I think you meant ordinalrank (or some other rank) from StatsBase.jl - it is probably confusing readers
2. internally you use sortperm(t) in the implementation; this behavior is deprecated; you should do sortperm(t, :) in the future; the reason for this deprecation is that sortperm(t) definition was inconsistent (starting from DataFrames.jl 1.4 it will start producing warnings); the same is for all sorting methods getting only a data frame as a source (a general recommendation: run all DataFramesMeta.jl tests with deprecation warnings enabled and see where warning is thrown)

Thank you!

[pdeffebach]

Yes, sorry. Both these are correct. I thought the sortperm issue was fixed, but it was not. I will fix this.

[bkamins]

internally you use sortperm(t) in the implementation; this behavior is deprecated;

Sorry - I have re-checked it. The code is OK