iszero(::SVector{0}) broken

[pablosanjose]

Something in v0.12.2 introduced a severe breaking change: it has made iszero(SVector{0,Int}()) a BoundsError, whereas before (in v0.12.1) it was true. In my opinion the old behavior made more sense, as indeed zero(SVector{0,Int}) === SVector{0,Int}()

[c42f]

Unexpected bugs tend to be breaking changes! Thanks for the report :-)

@tkf what do you think? Likely this is related to some refactoring done in #750 which now causes

julia> reduce((x,y)->true, SVector{0,Int}(), init=true)
ERROR: BoundsError: attempt to access ()
  at index [1]
Stacktrace:
 [1] getindex(::Tuple, ::Int64) at ./tuple.jl:24
 [2] getindex(::SArray{Tuple{0},Int64,1,0}, ::Int64) at /home/chris/.julia/dev/StaticArrays/src/SVector.jl:37
 [3] macro expansion at /home/chris/.julia/dev/StaticArrays/src/mapreduce.jl:129 [inlined]
 [4] _mapfoldl(::typeof(identity), ::var"#9#10", ::Colon, ::Bool, ::Size{(0,)}, ::SArray{Tuple{0},Int64,1,0}) at /home/chris/.julia/dev/StaticArrays/src/mapreduce.jl:116
 [5] _mapreduce(::Function, ::Function, ::Function, ::Bool, ::Size{(0,)}, ::SArray{Tuple{0},Int64,1,0}) at /home/chris/.julia/dev/StaticArrays/src/mapreduce.jl:113
 [6] _reduce(::Function, ::SArray{Tuple{0},Int64,1,0}, ::Function, ::Bool) at /home/chris/.julia/dev/StaticArrays/src/mapreduce.jl:198
 [7] reduce(::Function, ::SArray{Tuple{0},Int64,1,0}; dims::Function, init::Bool) at /home/chris/.julia/dev/StaticArrays/src/mapreduce.jl:184
 [8] top-level scope at REPL[2]:1

[tkf]

Oops, yes, there is a bug in empty array handling. #780 should fix this.

[c42f]

I'll do a quickfix release 0.12.3 containing this.

[c42f]

JuliaRegistries/General#14076

[pablosanjose]

That was quick! Thanks a lot!