Fix env handling in Cmd (#36039)

Matches behaviour in docs, adds test, fixes #32454.

Author: simonbyrne

base/cmd.jl

@@ -223,7 +223,7 @@ byteenv(env::AbstractArray{<:AbstractString}) =
 byteenv(env::AbstractDict) =
     String[cstr(string(k)*"="*string(v)) for (k,v) in env]
 byteenv(env::Nothing) = nothing
-byteenv(env::Union{AbstractVector{Pair{T}}, Tuple{Vararg{Pair{T}}}}) where {T<:AbstractString} =
+byteenv(env::Union{AbstractVector{Pair{T,V}}, Tuple{Vararg{Pair{T,V}}}}) where {T<:AbstractString,V} =
     String[cstr(k*"="*string(v)) for (k,v) in env]
 
 """

test/ambiguous.jl

@@ -312,7 +312,7 @@ end
         pop!(need_to_handle_undef_sparam, first(methods(Base.same_names)))
         @test_broken need_to_handle_undef_sparam == Set()
         pop!(need_to_handle_undef_sparam, which(Base._cat, Tuple{Any, AbstractArray}))
-        pop!(need_to_handle_undef_sparam, which(Base.byteenv, (Union{AbstractArray{Pair{T}, 1}, Tuple{Vararg{Pair{T}}}} where T<:AbstractString,)))
+        pop!(need_to_handle_undef_sparam, which(Base.byteenv, (Union{AbstractArray{Pair{T,V}, 1}, Tuple{Vararg{Pair{T,V}}}} where {T<:AbstractString,V},)))
         pop!(need_to_handle_undef_sparam, which(Base._cat, (Any, SparseArrays._TypedDenseConcatGroup{T} where T)))
         pop!(need_to_handle_undef_sparam, which(Base.float, Tuple{AbstractArray{Union{Missing, T},N} where {T, N}}))
         pop!(need_to_handle_undef_sparam, which(Base.zero, Tuple{Type{Union{Missing, T}} where T}))

test/spawn.jl

@@ -456,6 +456,13 @@ end
 @test Set([``, echocmd]) != Set([``, ``])
 @test Set([echocmd, ``, ``, echocmd]) == Set([echocmd, ``])
 
+# env handling (#32454)
+@test Cmd(`foo`, env=Dict("A"=>true)).env == ["A=true"]
+@test Cmd(`foo`, env=["A=true"]).env      == ["A=true"]
+@test Cmd(`foo`, env=("A"=>true,)).env    == ["A=true"]
+@test Cmd(`foo`, env=["A"=>true]).env     == ["A=true"]
+@test Cmd(`foo`, env=nothing).env         == nothing
+
 # test for interpolation of Cmd
 let c = setenv(`x`, "A"=>true)
     @test (`$c a`).env == String["A=true"]