ArgumentError when using integer() in @spec

[janpieper]

When I try to run ex_doc for my library, I am getting an ArgumentError in ExDoc.Formatter.HTML.Autolink.format_and_extract_typespec_placeholders/4. I was able to reproduce it with a simple mix new example project.

When I have the following module, everything is fine:

defmodule Example do
  @spec hello(String.t()) :: String.t()
  def hello(name), do: "Hello #{name}"
end

But, when I change the @spec to use integer() instead of String.t():

defmodule Example do
  @spec hello(integer()) :: String.t()
  def hello(people), do: "Hello, we are #{people} people!"
end

I get the following error:

$ ex_doc "Example" "v0.1.0" _build/dev/lib/example/ebin
=ERROR REPORT==== 21-Aug-2018::19:55:05.793109 ===
** Task <0.83.0> terminating
** Started from <0.82.0>
** When function  == #Fun<Elixir.ExDoc.Formatter.HTML.Autolink.30.36958183>
**      arguments == []
** Reason for termination == 
** {badarg,
       [{'Elixir.ExDoc.Formatter.HTML.Autolink',
            '-format_and_extract_typespec_placeholders/4-fun-0-',7,
            [{file,"lib/ex_doc/formatter/html/autolink.ex"},{line,240}]},
        {'Elixir.Macro','-do_traverse_args/4-fun-0-',4,
            [{file,"lib/macro.ex"},{line,277}]},
        {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',3,
            [{file,"lib/enum.ex"},{line,1397}]},
        {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',3,
            [{file,"lib/enum.ex"},{line,1397}]},
        {'Elixir.Macro',do_traverse,4,[{file,"lib/macro.ex"},{line,243}]},
        {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',3,
            [{file,"lib/enum.ex"},{line,1397}]},
        {'Elixir.Macro',do_traverse,4,[{file,"lib/macro.ex"},{line,243}]},
        {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',3,
            [{file,"lib/enum.ex"},{line,1397}]}]}

=CRASH REPORT==== 21-Aug-2018::19:55:05.796421 ===
  crasher:
    initial call: Elixir.ExDoc.Formatter.HTML.Autolink:'-all/3-fun-2-'/0
    pid: <0.83.0>
    registered_name: []
    exception exit: {badarg,
                        [{'Elixir.ExDoc.Formatter.HTML.Autolink',
                             '-format_and_extract_typespec_placeholders/4-fun-0-',
                             7,
                             [{file,"lib/ex_doc/formatter/html/autolink.ex"},
                              {line,240}]},
                         {'Elixir.Macro','-do_traverse_args/4-fun-0-',4,
                             [{file,"lib/macro.ex"},{line,277}]},
                         {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',
                             3,
                             [{file,"lib/enum.ex"},{line,1397}]},
                         {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',
                             3,
                             [{file,"lib/enum.ex"},{line,1397}]},
                         {'Elixir.Macro',do_traverse,4,
                             [{file,"lib/macro.ex"},{line,243}]},
                         {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',
                             3,
                             [{file,"lib/enum.ex"},{line,1397}]},
                         {'Elixir.Macro',do_traverse,4,
                             [{file,"lib/macro.ex"},{line,243}]},
                         {'Elixir.Enum','-map_reduce/3-lists^mapfoldl/2-0-',
                             3,
                             [{file,"lib/enum.ex"},{line,1397}]}]}
      in function  'Elixir.Task.Supervised':exit/4 (lib/task/supervised.ex, line 121)
      in call from 'Elixir.Task.Supervised':reply/5 (lib/task/supervised.ex, line 38)
    ancestors: [<0.82.0>]
    message_queue_len: 0
    messages: []
    links: [<0.82.0>]
    dictionary: []
    trap_exit: false
    status: running
    heap_size: 6772
    stack_size: 27
    reductions: 41541
  neighbours:
    neighbour:
      pid: <0.82.0>
      registered_name: []
      initial_call: {erlang,apply,2}
      current_function: {'Elixir.Task',await,2}
      ancestors: []
      message_queue_len: 0
      links: [<0.83.0>]
      trap_exit: false
      status: waiting
      heap_size: 28690
      stack_size: 25
      reductions: 9876
      current_stacktrace: [{'Elixir.Task',await,2,[{file,"lib/task.ex"},{line,491}]},
                  {'Elixir.Enum','-map/2-lists^map/1-0-',2,
                      [{file,"lib/enum.ex"},{line,1294}]},
                  {'Elixir.ExDoc.Formatter.HTML',run,2,
                      [{file,"lib/ex_doc/formatter/html.ex"},{line,21}]},
                  {'Elixir.Kernel.CLI','-exec_fun/2-fun-0-',3,
                      [{file,"lib/kernel/cli.ex"},{line,105}]}]

** (EXIT from #PID<0.82.0>) an exception was raised:
    ** (ArgumentError) argument error
        (ex_doc) lib/ex_doc/formatter/html/autolink.ex:240: anonymous fn/7 in ExDoc.Formatter.HTML.Autolink.format_and_extract_typespec_placeholders/4
        (elixir) lib/macro.ex:277: anonymous fn/4 in Macro.do_traverse_args/4
        (elixir) lib/enum.ex:1397: Enum."-map_reduce/3-lists^mapfoldl/2-0-"/3
        (elixir) lib/enum.ex:1397: Enum."-map_reduce/3-lists^mapfoldl/2-0-"/3
        (elixir) lib/macro.ex:243: Macro.do_traverse/4
        (elixir) lib/enum.ex:1397: Enum."-map_reduce/3-lists^mapfoldl/2-0-"/3
        (elixir) lib/macro.ex:243: Macro.do_traverse/4
        (elixir) lib/enum.ex:1397: Enum."-map_reduce/3-lists^mapfoldl/2-0-"/3

I am using the following versions:

$ mix --version
Erlang/OTP 21 [erts-10.0] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe]

Mix 1.6.6 (compiled with OTP 19)

$ ex_doc -v
ExDoc v0.18.4

[josevalim]

Thanks @janpieper! This seems to be fixed on the v0.19.1, although that requires Elixir v1.7:

[janpieper]

Hmmm... 0.18.4 has a bug which is fixed in 0.19, but this requires Elixir 1.7?

Do you know if I can use any earlier version than 0.18.4 that does not have this bug? Will try this tomorrow.

[janpieper]

• 0.18.0 - :x: RuntimeError
• 0.18.1 - :heavy_check_mark: Works fine!
• 0.18.2 - :x: ArgumentError
• 0.18.3 - :x: ArgumentError
• 0.18.4 - :x: ArgumentError
• 0.19.x - :grey_question: I don't have Elixir 1.7.x installed

[janpieper]

Btw.: When doing mix docs, it also works with 0.18.4 :astonished:

[milmazz]

@janpieper So, should we close this issue then? I could not reproduce your scenario with the latest release from ExDoc.

[josevalim]

when using an escript, the elixir source is bundled inside the escript, which causes the errors. But since both cases have been fixed in 0.19, we are good to go. :)