bundle config build.<gem> doesn't send multiple parameters to extconf.rb correctly

[brad1]

What works (bundler 1.7.2)

bundle config build.<gem> --with-opt-lib=... --with-client-lib=..., then
bundle install
This succeeds, giving the same results as:
gem install gem -v x.y.z -- --with-opt-lib=... --with-client-lib=....

From mkmf.log:

gcc ... -L"/path/to/lib" -L"/another/path"

What happens now (tried with bundler 1.17.1 and 2.0.1)

After the exact same steps as above:

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.  

...

/usr/bin/ruby -I /usr/lib64/ruby/2.6.0 -r ./siteconf20190130-29495-12z1ot5.rb \ 
 extconf.rb --with-opt-lib\=<...>\ --with-client-lib\=<...>

Notice that the build parameters are separated by an escaped space, because extconf.rb is being given the build parameters as one big string. Verified this using pry.

From mkmf.log:

gcc ... -L"/path/to/lib --with-client-lib=/another/path"

And the native extension fails to install because we can no longer find the required headers.

[amygitsthings]

I'm seeing this problem with 1.17.2 as well and I was not seeing this issue with bundler 1.15.4

[colby-swandale]

Can you please provide a Gemfile that we can use to reproduce this problem.

[amygitsthings]

I was trying to install the do_postgres gem and providing --with-pgsql-server-include and --with-pgsql-client-dir options

[coding-red-panda]

Running into similar problems with bundler 1.17.3 on ruby 2.1.6
Downgrading to bundler 1.15.4 makes it all work without issues.

Used the following command to generate output:

export DEBUG_RESOLVER=1
bundle 2> ~/debug_output.txt 1>~/stdio.txt &

see attached file
stdio.txt

[jeremy]

Quick repro:

# repro.rb
require 'bundler/inline'

system "bundle config --local build.mysql2 --with-mysql-config=mysqlconfig --example-argument"

gemfile do
  source 'https://rubygems.org'
  gem 'mysql2'
end

Running it:

$ ruby repro.rb 
You are replacing the current local value of build.mysql2, which is currently nil
Traceback (most recent call last):
…snip…
/Users/jeremy/.rbenv/versions/2.6.1/lib/ruby/site_ruby/2.6.0/bundler/installer/parallel_installer.rb:201:in `handle_error': Gem::Ext::BuildError: ERROR: Failed to build gem native extension. (Bundler::InstallError)

    current directory: /Users/jeremy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/mysql2-0.5.2/ext/mysql2
/Users/jeremy/.rbenv/versions/2.6.1/bin/ruby -I /Users/jeremy/.rbenv/versions/2.6.1/lib/ruby/site_ruby/2.6.0 -r ./siteconf20190306-75775-1csb26z.rb extconf.rb --with-mysql-config\=mysqlconfig\ --example-argument
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for rb_wait_for_single_fd()... yes
-----
Cannot find mysql_config at mysqlconfig --example-argument
…snip…

Here's the escaped build config from the extconf.rb invocation:

… extconf.rb --with-mysql-config\=mysqlconfig\ --example-argument

(can repro on Ruby 2.5, 2.6; RubyGems 2.7.3, 3.0.3; Bundler 1.17.3, 2.0.1)

[jeremy]

Quick fix:

require 'bundler/inline'

system "bundle config --local build.mysql2 --with-mysql-config=mysqlconfig --example-argument"

if ENV['SHELLSPLIT']
  require 'bundler/installer/gem_installer'
  require 'shellwords'

  module ShellsplitSpecSettings
    def spec_settings
      if settings = super
        Shellwords.shellsplit settings
      end
    end
  end

  Bundler::GemInstaller.prepend ShellsplitSpecSettings
end

gemfile do
  source 'https://rubygems.org'
  gem 'mysql2'
end

Running it:

$ SHELLSPLIT=1 ruby repro.rb
… extconf.rb --with-mysql-config\=mysqlconfig --example-argument

Looks like this was introduced by shellescaping/shelljoining arguments in the RubyGems installer: https://github.com/rubygems/rubygems/pull/2441/files#diff-352b7b3f2988f0f74c3e332074f59e09R74

So shellsplitting the spec_settings fixes it.

[deivid-rodriguez]

Thanks @jeremy, I created #7023 to add your patch to bundler.