release-1.8: Backports for julia 1.8-beta1/2

base/Base.jl

@@ -276,9 +276,6 @@ include("weakkeydict.jl")
 
 include("env.jl")
 
-# BinaryPlatforms, used by Artifacts
-include("binaryplatforms.jl")
-
 # functions defined in Random
 function rand end
 function randn end
@@ -336,6 +333,9 @@ using .Order
 include("sort.jl")
 using .Sort
 
+# BinaryPlatforms, used by Artifacts.  Needs `Sort`.
+include("binaryplatforms.jl")
+
 # Fast math
 include("fastmath.jl")
 using .FastMath

base/abstractarray.jl

@@ -1712,13 +1712,15 @@ end
 _cs(d, a, b) = (a == b ? a : throw(DimensionMismatch(
     "mismatch in dimension $d (expected $a got $b)")))
 
-function dims2cat(::Val{n}) where {n}
-    n <= 0 && throw(ArgumentError("cat dimension must be a positive integer, but got $n"))
-    ntuple(i -> (i == n), Val(n))
+function dims2cat(::Val{dims}) where dims
+    if any(≤(0), dims)
+        throw(ArgumentError("All cat dimensions must be positive integers, but got $dims"))
+    end
+    ntuple(in(dims), maximum(dims))
 end
 
 function dims2cat(dims)
-    if any(dims .<= 0)
+    if any(≤(0), dims)
         throw(ArgumentError("All cat dimensions must be positive integers, but got $dims"))
     end
     ntuple(in(dims), maximum(dims))

base/abstractdict.jl

@@ -189,7 +189,10 @@ empty(a::AbstractDict) = empty(a, keytype(a), valtype(a))
 empty(a::AbstractDict, ::Type{V}) where {V} = empty(a, keytype(a), V) # Note: this is the form which makes sense for `Vector`.
 
 copy(a::AbstractDict) = merge!(empty(a), a)
-copy!(dst::AbstractDict, src::AbstractDict) = merge!(empty!(dst), src)
+function copy!(dst::AbstractDict, src::AbstractDict)
+    dst === src && return dst
+    merge!(empty!(dst), src)
+end
 
 """
     merge!(d::AbstractDict, others::AbstractDict...)

base/abstractset.jl

@@ -3,7 +3,10 @@
 eltype(::Type{<:AbstractSet{T}}) where {T} = @isdefined(T) ? T : Any
 sizehint!(s::AbstractSet, n) = nothing
 
-copy!(dst::AbstractSet, src::AbstractSet) = union!(empty!(dst), src)
+function copy!(dst::AbstractSet, src::AbstractSet)
+    dst === src && return dst
+    union!(empty!(dst), src)
+end
 
 ## set operations (union, intersection, symmetric difference)
 

base/array.jl

@@ -402,17 +402,20 @@ julia> getindex(Int8, 1, 2, 3)
 """
 function getindex(::Type{T}, vals...) where T
     a = Vector{T}(undef, length(vals))
-    @inbounds for i = 1:length(vals)
-        a[i] = vals[i]
+    if vals isa NTuple
+        @inbounds for i in 1:length(vals)
+            a[i] = vals[i]
+        end
+    else
+        # use afoldl to avoid type instability inside loop
+        afoldl(1, vals...) do i, v
+            @inbounds a[i] = v
+            return i + 1
+        end
     end
     return a
 end
 
-getindex(::Type{T}) where {T} = (@inline; Vector{T}())
-getindex(::Type{T}, x) where {T} = (@inline; a = Vector{T}(undef, 1); @inbounds a[1] = x; a)
-getindex(::Type{T}, x, y) where {T} = (@inline; a = Vector{T}(undef, 2); @inbounds (a[1] = x; a[2] = y); a)
-getindex(::Type{T}, x, y, z) where {T} = (@inline; a = Vector{T}(undef, 3); @inbounds (a[1] = x; a[2] = y; a[3] = z); a)
-
 function getindex(::Type{Any}, @nospecialize vals...)
     a = Vector{Any}(undef, length(vals))
     @inbounds for i = 1:length(vals)

base/binaryplatforms.jl

@@ -608,7 +608,8 @@ const arch_march_isa_mapping = let
             "armv8_0" => get_set("aarch64", "armv8.0-a"),
             "armv8_1" => get_set("aarch64", "armv8.1-a"),
             "armv8_2_crypto" => get_set("aarch64", "armv8.2-a+crypto"),
-            "armv8_4_crypto_sve" => get_set("aarch64", "armv8.4-a+crypto+sve"),
+            "a64fx" => get_set("aarch64", "a64fx"),
+            "apple_m1" => get_set("aarch64", "apple_m1"),
         ],
         "powerpc64le" => [
             "power8" => get_set("powerpc64le", "power8"),

base/cmd.jl

@@ -262,6 +262,15 @@ setenv(cmd::Cmd, env::Pair{<:AbstractString}...; dir=cmd.dir) =
     setenv(cmd, env; dir=dir)
 setenv(cmd::Cmd; dir=cmd.dir) = Cmd(cmd; dir=dir)
 
+# split environment entry string into before and after first `=` (key and value)
+function splitenv(e::String)
+    i = findnext('=', e, 2)
+    if i === nothing
+        throw(ArgumentError("malformed environment entry"))
+    end
+    e[1:prevind(e, i)], e[nextind(e, i):end]
+end
+
 """
     addenv(command::Cmd, env...; inherit::Bool = true)
 
@@ -282,7 +291,7 @@ function addenv(cmd::Cmd, env::Dict; inherit::Bool = true)
             merge!(new_env, ENV)
         end
     else
-        for (k, v) in eachsplit.(cmd.env, "=")
+        for (k, v) in splitenv.(cmd.env)
             new_env[string(k)::String] = string(v)::String
         end
     end
@@ -301,7 +310,7 @@ function addenv(cmd::Cmd, pairs::Pair{<:AbstractString}...; inherit::Bool = true
 end
 
 function addenv(cmd::Cmd, env::Vector{<:AbstractString}; inherit::Bool = true)
-    return addenv(cmd, Dict(k => v for (k, v) in eachsplit.(env, "=")); inherit)
+    return addenv(cmd, Dict(k => v for (k, v) in splitenv.(env)); inherit)
 end
 
 """