HTML rendering error: nothing should not be printed

[Ankur-deDev]

Describe the bug
I am following the Bill Gates book example here and got the error:

ERROR: ArgumentError: nothing should not be printed; use show, repr, or custom output instead.

To Reproduce

• Follow Bill Gates book example.
• Replace html! with html (as html! does not exists, but not sure if this is correct).
• Within the app directory, in Julia execute the following command.
  using Genie; Genie.loadapp(); using BooksController; BooksController.billgatesbooks()

Expected behavior
I am not sure whether this error is a wrong behavior.

Additional context
versioninfo()
Julia Version 1.0.1
Commit 0d713926f8 (2018-09-29 19:05 UTC)
Platform Info:
OS: Linux (x86_64-pc-linux-gnu)
CPU: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-6.0.0 (ORCJIT, skylake)
Environment:
JULIA_REVISE = auto

pkg> st
Status ~/Tester/Project.toml
[c43c736e] Genie v0.10.1
[682c06a0] JSON v0.21.0
[39ec1447] Millboard v0.2.0
[295af30f] Revise v2.1.6

Stack
ERROR: ArgumentError: nothing should not be printed; use show, repr, or custom output instead.
Stacktrace:

[1] print(::Base.GenericIOBuffer{Array{UInt8,1}}, ::Nothing) at ./show.jl:566
[2] print(::Base.GenericIOBuffer{Array{UInt8,1}}, ::Nothing, ::String) at ./strings/io.jl:42
[3] normal_element(::Array{Union{Nothing, String},1}, ::String) at /home/user/.julia/packages/Genie/LHtIg/src/Flax.jl:140
[4] normal_element(::getfield(Genie.Renderer, Symbol("##33#37")), ::String, ::Array{Pair{Symbol,Any},1}) at /home/user/.julia/packages/Genie/LHtIg/src/Flax.jl:116
[5] #body#36 at ./none:2 [inlined]
[6] body at ./none:2 [inlined]
[7] (::getfield(Genie.Renderer, Symbol("##30#34")))() at /home/user/Books/build/FlaxViews/a61fb571d6f0fc6e87fc97c269d5d6c775adde87.jl:4
[8] normal_element at /home/user/.julia/packages/Genie/LHtIg/src/Flax.jl:116 [inlined]
[9] #html#32 at ./none:2 [inlined]
[10] #html at ./none:0 [inlined]
[11] func_a61fb571d6f0fc6e87fc97c269d5d6c775adde87() at /home/user/Books/build/FlaxViews/a61fb571d6f0fc6e87fc97c269d5d6c775adde87.jl:4
[12] #invokelatest#1 at ./essentials.jl:697 [inlined]
[13] invokelatest at ./essentials.jl:696 [inlined]
[14] |> at ./operators.jl:813 [inlined]
[15] #tohtml#2(::Symbol, ::Module, ::Base.Iterators.Pairs{Symbol,Array{BooksController.Book,1},Tuple{Symbol},NamedTuple{(:books,),Tuple{Array{BooksController.Book,1}}}}, ::Function, ::Symbol, ::Symbol) at /home/user/.julia/packages/Genie/LHtIg/src/Renderer.jl:52

[essenciary]

@Ankur-deDev Sorry, I need to update that, the API has been massively updated recently, in preparation for v1. I'll take a look and update the README.

[essenciary]

@Ankur-deDev I took a look, I think the only thing needed was to just replace html! and json! with html and json. I updated and pushed the docs.

[Ankur-deDev]

Thanks for your quick action.
I moved my .julia and tried again, but got an error earlier with the following steps:

pkg> add Genie
julia> using Genie
julia> Genie.newapp("Repro")
ERROR: IOError: open: no such file or directory (ENOENT)
Stacktrace:
 [1] uv_error at ./libuv.jl:85 [inlined]
 [2] open(::String, ::UInt8, ::Int64) at ./filesystem.jl:81
 [3] open at ./filesystem.jl:73 [inlined]
 [4] sendfile(::String, ::String) at ./file.jl:743
 [5] #cp#12(::Bool, ::Bool, ::Function, ::String, ::String) at ./file.jl:336
 [6] cp at ./file.jl:330 [inlined]
 [7] copy_microstack_app(::String) at /home/user/.julia/packages/Genie/NB11Y/src/REPL.jl:36
 [8] #newapp#7(::Bool, ::Bool, ::Bool, ::Function, ::String) at /home/user/.julia/packages/Genie/NB11Y/src/REPL.jl:150
 [9] #newapp at ./none:0 [inlined]
 [10] #newapp#15 at /home/user/.julia/packages/Genie/NB11Y/src/Genie.jl:92 [inlined]
 [11] newapp(::String) at /home/user/.julia/packages/Genie/NB11Y/src/Genie.jl:92
 [12] top-level scope at none:0

(v1.0) pkg> st
    Status `~/.julia/environments/v1.0/Project.toml`
  [c43c736e] Genie v0.11.1

[essenciary]

@Ankur-deDev Sorry, yes, completely unrelated issue :-/ Can you please update to latest master?

pkg> add https://github.com/GenieFramework/Genie.jl

Until the new v0.13.1 will be registered.

[Ankur-deDev]

Great, I tried with the new version and was able to create the app.
I followed the books example again, and it works fine as long as the HTML is in the controller.
Once I follow the steps here to render the view I get back the original error:

julia> using Genie; Genie.loadapp(); 
 _____         _
|   __|___ ___|_|___
|  |  | -_|   | | -_|
|_____|___|_|_|_|___|

┌ Info: 
│ Starting Genie in >> DEV << mode 
└ 
[ Info: Logging to file at /home/user/Repro/log/dev.log 
[ Info: Recompiling stale cache file /home/user/.julia/compiled/v1.1/BooksController.ji for BooksController [top-level]

julia> using BooksController

julia> BooksController.billgatesbooks()
2019-08-09 09:21:52:DEBUG:Main: 🚨  Flax view app/resources/books/views/billgatesbooks.jl.html build build/FlaxViews/8f5e1d5a4b008396d4cd553ad4a7c2a06f9eb7c7.jl is stale
2019-08-09 09:21:53:DEBUG:Main: 🚨  Flax view app/layouts/app.jl.html build build/FlaxViews/a61fb571d6f0fc6e87fc97c269d5d6c775adde87.jl is stale
ERROR: ArgumentError: `nothing` should not be printed; use `show`, `repr`, or custom output instead.
Stacktrace:
 [1] print(::Base.GenericIOBuffer{Array{UInt8,1}}, ::Nothing) at ./show.jl:566
 [2] print(::Base.GenericIOBuffer{Array{UInt8,1}}, ::Nothing, ::String) at ./strings/io.jl:42
 [3] normal_element(::Array{Union{Nothing, String},1}, ::String) at /home/user/.julia/packages/Genie/chAqw/src/Flax.jl:135
 [4] normal_element(::getfield(Genie.Renderer, Symbol("##30#34")), ::String, ::Array{Pair{Symbol,Any},1}) at /home/user/.julia/packages/Genie/chAqw/src/Flax.jl:111
 [5] #body#34(::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::Function, ::Function) at ./none:2
 [6] body at ./none:2 [inlined]
 [7] (::getfield(Genie.Renderer, Symbol("##27#31")))() at /home/user/Repro/build/FlaxViews/a61fb571d6f0fc6e87fc97c269d5d6c775adde87.jl:4
 [8] normal_element at /home/user/.julia/packages/Genie/chAqw/src/Flax.jl:111 [inlined]
 [9] #html#30 at ./none:2 [inlined]
 [10] #html at ./none:0 [inlined]
 [11] func_a61fb571d6f0fc6e87fc97c269d5d6c775adde87() at /home/user/Repro/build/FlaxViews/a61fb571d6f0fc6e87fc97c269d5d6c775adde87.jl:4
 [12] #invokelatest#1 at ./essentials.jl:742 [inlined]
 [13] invokelatest at ./essentials.jl:741 [inlined]
 [14] |> at ./operators.jl:813 [inlined]
 [15] #tohtml#2(::Symbol, ::Module, ::Base.Iterators.Pairs{Symbol,Array{BooksController.Book,1},Tuple{Symbol},NamedTuple{(:books,),Tuple{Array{BooksController.Book,1}}}}, ::Function, ::Symbol, ::Symbol) at /home/user/.julia/packages/Genie/chAqw/src/Renderer.jl:54
 [16] #tohtml at ./none:0 [inlined]
 [17] #html#5(::Symbol, ::Module, ::Int64, ::Dict{String,String}, ::Base.Iterators.Pairs{Symbol,Array{BooksController.Book,1},Tuple{Symbol},NamedTuple{(:books,),Tuple{Array{BooksController.Book,1}}}}, ::Function, ::Symbol, ::Symbol) at /home/user/.julia/packages/Genie/chAqw/src/Renderer.jl:68
 [18] (::getfield(Genie.Renderer, Symbol("#kw##html")))(::NamedTuple{(:books,),Tuple{Array{BooksController.Book,1}}}, ::typeof(Genie.Renderer.html), ::Symbol, ::Symbol) at ./none:0
 [19] billgatesbooks() at /home/user/Repro/app/resources/books/BooksController.jl:19
 [20] top-level scope at none:0

The last commit in JuliaLang/julia/base/show.jl could be related to that.

[essenciary]

@Ankur-deDev I can't reproduce - I have a slightly different version of the test app which works fine.

julia> BooksController.billgatesbooks()
2019-08-09 09:58:28:DEBUG:Main:SQL QUERY: SELECT "books"."id" AS "books_id", "books"."title" AS "books_title", "books"."author" AS "books_author", "books"."cover" AS "books_cover" FROM "books" ORDER BY books.id ASC
  0.186826 seconds (426.70 k allocations: 21.421 MiB, 6.84% gc time)
HTTP.Messages.Response:
"""
HTTP/1.1 200 OK
Content-Type: text/html

<html lang="en" ><head ><title >Genie Admin</title></head><body ><h1 >Books admin</h1><h1 >Bill Gates' top 7 "recommended books!!"</h1><ul ><li ><p >The Best We Could Do by Thi Bui</p></li><li ><p >Evicted: Poverty and Profit in the American City by Matthew Desmond</p></li><li ><p >Believe Me: A Memoir of Love, Death, and Jazz Chickens by Eddie Izzard</p></li><li ><p >The Sympathizer! by Viet Thanh Nguyen</p></li><li ><p >Energy and Civilization, A History by Vaclav Smil</p></li><li ><p >Leonardo da Vinci by Walter Isaacson</p></li><li ><p >Identity by Francis Fukuyama</p></li></ul></body></html>"""

Can you please zip the whole app and share it with me?

[Ankur-deDev]

Hi, Thanks a lot for having a look, I have sent you the tarball.

[essenciary]

@Ankur-deDev Thanks - where is it?

[essenciary]

This was actually caused by a sneaky bug, sorry for it. Should be all fixed on the latest #master!

[essenciary]

Closing this as it should be resolved on the latest master. Please reopen if that's not the case.

[Ankur-deDev]

I confirm it is working as expected now. Thanks a lot for the quick fix!

I had sent the tarball to the address defined in GenieFramework/Genie.jl/Project.toml but it was rejected with the following message (sorry for not realizing earlier that the mail did not go through):

SMTP error from remote mail server after end of data:
552-5.7.0 This message was blocked because its content presents a potential
552-5.7.0 security issue. Please visit
552-5.7.0 https://support.google.com/mail/?p=BlockedMessage to review our
552 5.7.0 message content and attachment content guidelines. o4si32831595ejn.27 - gsmtp

[essenciary]

@Ankur-deDev Thanks for the update, happy that it works now!