Codecov Report

Merging #136 (7eeb2dc) into master (b7f7418) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #136   +/-   ##
=======================================
  Coverage   97.29%   97.29%           
=======================================
  Files           4        4           
  Lines         775      775           
=======================================
  Hits          754      754           
  Misses         21       21           

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CI still passed but not sure if that just means that this piece of code is untested.

I wondered about that too. https://app.codecov.io/gh/JuliaIO/Tar.jl/blob/master/src/extract.jl indicates it's tested. Presumably all AbstractStrings used in the tests are already String or SubString{String}:

julia> struct A end; struct B end;

julia> a = A()
A()

julia> convert(Union{A,B}, a)
A()

So it's only formally needed, to handle cases like

julia> struct C end

julia> Base.convert(::Type{A}, c::C) = A(); Base.convert(::Type{B}, c::C) = B();

julia> convert(Union{A, B}, C())
ERROR: MethodError: Cannot `convert` an object of type 
  C to an object of type 
  Union{A, B}
Closest candidates are:
  convert(::Type{T}, ::T) where T at essentials.jl:205
Stacktrace:
 [1] top-level scope
   @ REPL[33]:1

This should be safe to merge now, but no rush either.