JuliaData / JuliaData/SentinelArrays.jl

`map!(f,dest::ChainedVector,src::AbstractArray)` doesn't work for shorter `src`

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Dominant language
Julia
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Description

In case the src array is shorter an error is thrown:

julia> map!(i->-i,ChainedVector([[1,2,3]]),[10:11...])
ERROR: MethodError: no method matching getindex(::Nothing, ::Int64)
The function `getindex` exists, but no method is defined for this combination of argument types.
Stacktrace:
 [1] map!(f::var"#1#2", x::ChainedVector{Int64, Vector{Int64}}, A::Vector{Int64})
   @ SentinelArrays ~/.julia/packages/SentinelArrays/vt8A6/src/chainedvector.jl:781
 [2] top-level scope
   @ REPL[8]:1

This is due to the fact that the implementation iterates the destination array instead of the src array.

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Research direction

Reproduce the reported shorter-src example and inspect sentinelarrays.jl:781, where map! is shown in the stack trace. Confirm the failure for a shorter src and verify that the same call completes without a MethodError after the destination and source lengths are handled as described.

Written by the indexing model from the issue text.

Assessment

Tech stack
julia
Domain
data
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
52/100

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