support for non-markdown docstrings is broken?

[stevengj]

One of the original key points of the docsystem design was that @doc could use any Julia object as a docstring, and writemime would be used to convert that object to different formats as needed. The default would be Markdown objects, but other objects would also be supported.

This seems to have been broken in a recent Julia 0.5 commit, causing JuliaPy/PyPlot.jl#198 because PyPlot uses "lazy" documentation objects that fetch docstrings from Python only when needed in order to speed up using PyPlot.

For example, @doc 15 f(x) = 2 used to work in Julia 0.4, associating 15 as the documentation object for f, but it now gives:

ERROR: MethodError: Cannot `convert` an object of type Int64 to an object of type Base.Markdown.MD
This may have arisen from a call to the constructor Base.Markdown.MD(...),
since type constructors fall back to convert methods.
Closest candidates are:
  convert{T}(::Type{T}, ::T)
  (::Type{BoundsError})(::ANY)
  (::Type{BoundsError})(::ANY, ::ANY)
  ...
 in convert(::Type{Nullable{Base.Markdown.MD}}, ::Nullable{Int64}) at ./nullable.jl:32
 in Base.Docs.DocStr(::Int64, ::Dict{Symbol,Any}) at ./docs/Docs.jl:134
 in eval(::Module, ::Any) at ./boot.jl:267
``

[MichaelHatherly]

Sorry about that @stevengj, will fix asap.

[stevengj]

Thanks for looking into it!