[1.8.0+] Global build config ignored

[felixbuenemann]

Example (bundler 1.7.13/1.8.2 on Mac OS X 10.10.2 w/homebrew):

brew install libarchive
# keg only lib requires build flags to be picked up
bundle config build.libarchive-ruby --with-opt-dir=$(brew --prefix libarchive)

Gemfile:

source 'https://rubygems.org'
gem 'libarchive-ruby'

On bundler 1.7.13 extconf.rb --with-opt-dir=/usr/local/opt/libarchive is called during installation of the gem by bundler:

/usr/local/opt/ruby/bin/ruby -r ./siteconf20150216-25666-1oqlbrx.rb extconf.rb --with-opt-dir=/usr/local/opt/libarchive
checking for main() in -larchive... yes
checking for archive.h... yes
checking for rb_string_value_cstr() in ruby.h... yes
checking for RETURN_ENUMERATOR in ruby.h... yes
checking for rb_proc_arity() in ruby.h... yes
checking for archive_read_support_format_raw() in archive.h... yes
creating extconf.h
creating Makefile

On 1.8.0+ (tested up to 1.8.2) the --with-opt-dir flag is not passed to extconf.rb and consequently compilation fails:

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

    /usr/local/opt/ruby/bin/ruby -r ./siteconf20150216-25453-apz89b.rb extconf.rb
checking for main() in -larchive... yes
checking for archive.h... no
libarchive dev files

[felixbuenemann]

I tracked this down to commit ca7b782. Reverting it fixes compilation on 1.8.2.

[indirect]

Ugh, definitely need to add a test to make sure that global config is found and not found correctly. Thanks for reporting this!

[felixbuenemann]

This is still broken in 1.9.1.

[indirect]

Thanks for following up! I'll look at this as soon as possible.

[felixbuenemann]

No worries, let me know if you need more info. Downgraded back to 1.7.x for now.

[indirect]

Finally tracked this down! The underlying problem turned out to be not configuration but thread-safety: in Bundler 1.8 we switched to using threads to install gems instead of forking, and gem build options are set in a global variable. We've synchronized it for now using a Monitor, but hopefully we can figure out a non-global way to handle build options in the future.

[felixbuenemann]

That sounds like a fun one to debug! ;-)
I'll check it out once a new version gets released.

[indirect]

Released a fix for this in version 1.8.6, and it will also be fixed in 1.9.2, which I'll release as soon as CI is green. Thanks for the bug report!