findfirst, findlast, etc. appears to break due to keys

[dahong67]

findfirst appears to sometimes break, e.g., in this MWE:

julia> using IdentityRanges
julia> findfirst(x -> x < 0, IdentityRange(-2:2))
ERROR: BoundsError: attempt to access 5-element IdentityRange{Int64} with indices -2:2 at index [3]
Stacktrace:
 [1] throw_boundserror(::IdentityRange{Int64}, ::Int64) at ./abstractarray.jl:541
 [2] getindex at /Users/dahong67/.julia/packages/IdentityRanges/liKDH/src/IdentityRanges.jl:70 [inlined]
 [3] findnext(::var"#9#10", ::IdentityRange{Int64}, ::Int64) at ./array.jl:1810
 [4] findfirst(::Function, ::IdentityRange{Int64}) at ./array.jl:1861
 [5] top-level scope at REPL[8]:1

Similarly for findlast, findall.

It seems to happen because keys currently always start at 1:

julia> using IdentityRanges
julia> keys(IdentityRange(-2:2))
5-element LinearIndices{1,Tuple{UnitRange{Int64}}}:
 1
 2
 3
 4
 5

Is this the intended behavior?

Interestingly, related to #9, Base.IdentityUnitRange behaves differently:

julia> keys(Base.IdentityUnitRange(-2:2))
5-element LinearIndices{1,Tuple{Base.IdentityUnitRange{UnitRange{Int64}}}} with indices -2:2:
 -2
 -1
  0
  1
  2

[timholy]

Nice catch! Fundamentally this comes about because of this:

julia> r = Base.IdentityUnitRange(-2:2);

julia> rax = axes(r)[1]
Base.IdentityUnitRange(-2:2)

vs

julia> r = IdentityRange(-2:2)
IdentityRange(-2:2)

julia> rax = axes(r)[1]
-2:2

Care to try making a fix?

[dahong67]

Thanks! Oh interesting, yes I would be happy to attempt a fix. I'll make a PR. :)