JuliaCollections / JuliaCollections/DataStructures.jl

append!(l1::MutableLinkedList, l2::MutableLinkedList) fails for empty l2

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Julia
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Description

The append! function on master currently assumes l2.node.next != l2.node != l2.node.prev and fails if isempty(l2).

E.g.,

A = MutableLinkedList{Int}(1,2,3)
B = MutableLinkedList{Int}()
append!(A,B) # endless loop

This is not directly related to the more general issues #739 #886 #794 , which have been fixed on master.

The simplest solution seems to be adding a check for isempty(l2)? I can try making such PR later.
There don't seem to be any issues if isempty(l1).

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Research direction

Open src/mutable_list.jl at the append! implementation around line 153 and reproduce the A/B example with an empty l2. Trace that case and verify that append!(A, B) terminates; done means the empty-l2 scenario no longer enters an endless loop.

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
62/100

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