All tests fail with "ERROR: Can't find header dir for ruby" message

[maxirmx]

• This happens on all platforms including Windows (so it is not related to tebako)
• The message is generated by RubyInline gem attempting to recompile embedded C code
• RubiInline is called by png

[ronaldtse]

Thanks @maxirmx for investigating. @opoudjis do we need the png gem?

[maxirmx]

RubyInline creates a kind of binary extension for a gem (png in our case)
But the extension is created on require not on gem/bundle install.
Tebako does bundle install into pristine environment and packages whatever is created there. So there is no binary for inlined code

[maxirmx]

I can add a custom step to tebako so that some Ruby code is executed before packaging
I guess if we call require png there it will solve the problem

[ronaldtse]

I actually wonder if we need the png gem at all in Metanorma. If not then we don't need rubyinline. However, I'm also not sure if there is a generic way of solving this.

[maxirmx]

We can have bundler plugin that implements post install hook that calls require for all gems, referencing RubyInline

[ronaldtse]

Calling "require" on all bundled gems is a reasonable requirement, for example, Opal also does that.

As a side note, I wonder if we should also consider the bundler "vendor" mode which places all the gems in one directory that allows easy packaging.

[maxirmx]

png is outdated (2015). I use the newer gem: https://rubygems.org/gems/libpng-ruby
Sorry, I did not notice it earlier

[opoudjis]

And I have removed the png gem from standoc; it turns out we didn't need it after all.

[ronaldtse]

Great, let's get that gem removed.

[maxirmx]

I think this issue can be closed
Keeping possible improvement in #179