Column metadata anchored to wrong column after insertion of new colums

[mathieu17g]

Hello,

I stumbled on an issue where colmetadata are not translated with the column tafter inserting a new column before.
I have not found this issue mentionned amond recent issues with the metadata keyword.

Here is an example to reproduce it:

julia> versioninfo()
Julia Version 1.8.2
Commit 36034abf26 (2022-09-29 15:21 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: 8 × Intel(R) Core(TM) i5-10400H CPU @ 2.60GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-13.0.1 (ORCJIT, skylake)
  Threads: 8 on 8 virtual cores
Environment:
  JULIA_EDITOR = code
  JULIA_NUM_THREADS = 8

(myproject) pkg> status DataFrames
Project myproject v0.1.0
Status `C:\...\code_julia\myproject\Project.toml`
  [a93c6f00] DataFrames v1.4.2

julia> df = DataFrame(B=[1, 2], C=[3.0, 4.0])
2×2 DataFrame
 Row │ B      C       
     │ Int64  Float64 
─────┼────────────────
   1 │     1      3.0
   2 │     2      4.0

julia> colmetadata!(df, :C, "label", "last column"; style=:note)
2×2 DataFrame
 Row │ B      C       
     │ Int64  Float64 
─────┼────────────────
   1 │     1      3.0
   2 │     2      4.0

julia> colmetadatakeys(df) |> collect
1-element Vector{Pair{Symbol, Base.KeySet{String, Dict{String, Tuple{Any, Any}}}}}:
 :C => ["label"]

julia> insertcols!(df, 1, :A => ["a", "b"])
2×3 DataFrame
 Row │ A       B      C       
     │ String  Int64  Float64 
─────┼────────────────────────
   1 │ a           1      3.0
   2 │ b           2      4.0

julia> colmetadatakeys(df) |> collect
1-element Vector{Pair{Symbol, Base.KeySet{String, Dict{String, Tuple{Any, Any}}}}}:
 :B => ["label"]
julia> 

[mathieu17g]

The testset on functions that should not affect metadata in test/metadata.jl, tests only the insertion of a column at the end:

DataFrames.jl/test/metadata.jl

Line 824 in a1dc899

x -> insertcols!(x, :newcol => 1, makeunique=true),

[mathieu17g]

Maybe the issue is linked with the fact that colmetadata are indexes by column number in DataFrame struct

DataFrames.jl/src/dataframe/dataframe.jl

Lines 172 to 176 in 34624f3

	mutable struct DataFrame <: AbstractDataFrame
	columns::Vector{AbstractVector}
	colindex::Index
	metadata::Union{Nothing, Dict{String, Tuple{Any, Any}}}
	colmetadata::Union{Nothing, Dict{Int, Dict{String, Tuple{Any, Any}}}}

And that there is no insertion routine in insertcols! on colmetadata, as there is on Index and Columns

DataFrames.jl/src/abstractdataframe/abstractdataframe.jl

Lines 3240 to 3241 in abbed11

	insert!(index(dfp), col_ind, name)
	insert!(_columns(dfp), col_ind, item_new)

[bkamins]

This is a bug. I will fix it. Thank you for reporting.

[bkamins]

Fixed in #3220