avoid depending on heavily invalidating pacakges

Project.toml

@@ -7,7 +7,6 @@ Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"
 DataAPI = "9a962f9c-6df0-11e9-0e5d-c546b8b5ee8a"
 DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
 Future = "9fa8497b-333b-5362-9e8d-4d0656e87820"
-InlineStrings = "842dd82b-1e85-43dc-bf29-5d0ee9dffc48"
 InvertedIndices = "41ab1584-1d38-5bbf-9106-f11c6c58b48f"
 IteratorInterfaceExtensions = "82899510-4779-5014-852e-03e436cf321d"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
@@ -19,21 +18,25 @@ PrettyTables = "08abe8d2-0d0c-5749-adfa-8a2ac140af0d"
 Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
-SentinelArrays = "91c51154-3ec4-41a3-a24f-3f23e20d615c"
 SortingAlgorithms = "a2af1166-a08f-5f64-846c-94a0d3cef48c"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 TableTraits = "3783bdb8-4a98-5b6b-af9a-565f29a5fe9c"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 Unicode = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
 
+[weakdeps]
+SentinelArrays = "91c51154-3ec4-41a3-a24f-3f23e20d615c"
+
+[extensions]
+DataFramesSentinelArraysExt = "SentinelArrays"
+
 [compat]
 CategoricalArrays = "0.10.0, 1"
 Combinatorics = "1.0.2"
 Compat = "4.2"
 DataAPI = "1.16.0"
 DataStructures = "0.18, 0.19"
 DataValues = "0.4.13"
-InlineStrings = "1.3.0"
 InvertedIndices = "1.3"
 IteratorInterfaceExtensions = "0.1.1, 1"
 Missings = "0.4.2, 1"
@@ -57,13 +60,15 @@ CategoricalArrays = "324d7699-5711-5eae-9e2f-1d82baa6b597"
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
 DataValues = "e7dc6d0d-1eca-5fa6-8ad6-5aecde8b7ea5"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
+InlineStrings = "842dd82b-1e85-43dc-bf29-5d0ee9dffc48"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
 OffsetArrays = "6fe1bfb0-de20-5000-8ca7-80f57d26f881"
+SentinelArrays = "91c51154-3ec4-41a3-a24f-3f23e20d615c"
 ShiftedArrays = "1277b4bf-5013-50f5-be3d-901d8477a67a"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 StableRNGs = "860ef19b-820b-49d6-a774-d7a799459cd3"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
 
 [targets]
-test = ["CategoricalArrays", "Combinatorics", "DataValues", "Dates", "Logging", "OffsetArrays", "ShiftedArrays", "SparseArrays", "StableRNGs", "Test", "Unitful"]
+test = ["CategoricalArrays", "Combinatorics", "DataValues", "Dates", "InlineStrings", "Logging", "OffsetArrays", "SentinelArrays", "ShiftedArrays", "SparseArrays", "StableRNGs", "Test", "Unitful"]

ext/DataFramesSentinelArraysExt.jl

@@ -0,0 +1,22 @@
+module DataFramesSentinelArraysExt
+
+using DataFrames
+using DataFrames: SymbolOrString
+using SentinelArrays: ChainedVector
+
+# definition needed to avoid dispatch ambiguity between the `reduce(vcat, ...)`
+# methods defined in DataFrames and the one defined in SentinelArrays for
+# `ChainedVector`
+Base.reduce(::typeof(vcat),
+    dfs::Union{ChainedVector{AbstractDataFrame,<:AbstractVector{AbstractDataFrame}},
+        ChainedVector{DataFrame,<:AbstractVector{DataFrame}},
+        ChainedVector{SubDataFrame,<:AbstractVector{SubDataFrame}},
+        ChainedVector{Union{DataFrame,SubDataFrame},<:AbstractVector{Union{DataFrame,SubDataFrame}}}};
+    cols::Union{Symbol,AbstractVector{Symbol},
+        AbstractVector{<:AbstractString}}=:setequal,
+    source::Union{Nothing,SymbolOrString,
+        Pair{<:SymbolOrString,<:AbstractVector}}=nothing,
+    init::AbstractDataFrame=DataFrame()) =
+    reduce(vcat, collect(AbstractDataFrame, dfs), cols=cols, source=source, init=init)
+
+end # module

src/DataFrames.jl

@@ -25,8 +25,6 @@ import Base.keepat!,
        Base.stack,
        LinearAlgebra.norm,
        PrecompileTools,
-       SentinelArrays,
-       InlineStrings,
        DataAPI,
        DataAPI.allcombinations,
        DataAPI.All,

src/abstractdataframe/iteration.jl

@@ -748,19 +748,6 @@ function Base.reduce(::typeof(vcat),
     return res
 end
 
-# definition needed to avoid dispatch ambiguity
-Base.reduce(::typeof(vcat),
-    dfs::Union{SentinelArrays.ChainedVector{AbstractDataFrame,<:AbstractVector{AbstractDataFrame}},
-        SentinelArrays.ChainedVector{DataFrame,<:AbstractVector{DataFrame}},
-        SentinelArrays.ChainedVector{SubDataFrame,<:AbstractVector{SubDataFrame}},
-        SentinelArrays.ChainedVector{Union{DataFrame,SubDataFrame},<:AbstractVector{Union{DataFrame,SubDataFrame}}}};
-    cols::Union{Symbol,AbstractVector{Symbol},
-        AbstractVector{<:AbstractString}}=:setequal,
-    source::Union{Nothing,SymbolOrString,
-        Pair{<:SymbolOrString,<:AbstractVector}}=nothing,
-    init::AbstractDataFrame=DataFrame()) =
-    reduce(vcat, collect(AbstractDataFrame, dfs), cols=cols, source=source, init=init)
-
 function _vcat(dfs::AbstractVector{AbstractDataFrame};
     cols::Union{Symbol,AbstractVector{Symbol},
         AbstractVector{<:AbstractString}}=:setequal)

test/dataframe.jl

@@ -1942,10 +1942,11 @@ end
     @test_throws ArgumentError reduce(vcat, dfs, cols=:union, source=:x, init=DataFrame(c=[1]))
 end
 
-@testset "vcat ChainedVector ambiguity" begin
-    dfs = DataFrames.SentinelArrays.ChainedVector([[DataFrame(a=1)], [DataFrame(a=2)]])
+import SentinelArrays
+@testset "vcat ChainedVector" begin
+    dfs = SentinelArrays.ChainedVector([[DataFrame(a=1)], [DataFrame(a=2)]])
     @test reduce(vcat, dfs) == DataFrame(a=1:2)
-    dfs = DataFrames.SentinelArrays.ChainedVector([[DataFrame(a=1)], [DataFrame(b=2)]])
+    dfs = SentinelArrays.ChainedVector([[DataFrame(a=1)], [DataFrame(b=2)]])
     @test reduce(vcat, dfs, cols=:union, source=:x, init=DataFrame(c=[])) ≅
           DataFrame(c=missing, a=[1, missing], b=[missing, 2], x=1:2)
 end