[Ruby] Solution for ERROR: cannot discover where libxml2 is located on your system. please make sure `pkg-config` is installed.
Tadashi Shigeoka · Sun, August 6, 2017
While installing Ruby on Rails 5 with bundle install, I encountered an error where nokogiri couldn’t be installed due to missing libxml2.
It was simply that the libraries required for nokogiri installation weren’t installed on macOS, but I was able to resolve it successfully, so I’ll introduce the solution.
Error Message: nokogiri Cannot Be Installed Due to Missing libxml2
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory: /Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/nokogiri-1.8.0/ext/nokogiri
/Users/yourname/.rvm/rubies/ruby-2.4.1/bin/ruby -r ./siteconf20170812-11295-n8mq5e.rb extconf.rb
checking if the C compiler accepts ... yes
checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... no
Building nokogiri using packaged libraries.
Using mini_portile version 2.2.0
checking for iconv.h... yes
checking for gzdopen() in -lz... yes
checking for iconv using --with-opt-* flags... yes
************************************************************************
IMPORTANT NOTICE:
Building Nokogiri with a packaged version of libxml2-2.9.4
with the following patches applied:
- 0001-Fix-comparison-with-root-node-in-xmlXPathCmpNodes.patch
- 0002-Fix-XPointer-paths-beginning-with-range-to.patch
- 0003-Disallow-namespace-nodes-in-XPointer-ranges.patch
Team Nokogiri will keep on doing their best to provide security
updates in a timely manner, but if this is a concern for you and want
to use the system library instead; abort this installation process and
reinstall nokogiri as follows:
gem install nokogiri -- --use-system-libraries
[--with-xml2-config=/path/to/xml2-config]
[--with-xslt-config=/path/to/xslt-config]
If you are using Bundler, tell it to use the option:
bundle config build.nokogiri --use-system-libraries
bundle install
Note, however, that nokogiri is not fully compatible with arbitrary
versions of libxml2 provided by OS/package vendors.
************************************************************************
Extracting libxml2-2.9.4.tar.gz into tmp/x86_64-apple-darwin15.6.0/ports/libxml2/2.9.4... OK
Running git apply with
/Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/nokogiri-1.8.0/patches/libxml2/0001-Fix-comparison-with-root-node-in-xmlXPathCmpNodes.patch... OK
Running git apply with
/Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/nokogiri-1.8.0/patches/libxml2/0002-Fix-XPointer-paths-beginning-with-range-to.patch... OK
Running git apply with
/Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/nokogiri-1.8.0/patches/libxml2/0003-Disallow-namespace-nodes-in-XPointer-ranges.patch... OK
Running 'configure' for libxml2 2.9.4... OK
Running 'compile' for libxml2 2.9.4... ERROR, review
'/Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/nokogiri-1.8.0/ext/nokogiri/tmp/x86_64-apple-darwin15.6.0/ports/libxml2/2.9.4/compile.log' to see what
happened. Last lines are:
========================================================================
unsigned short* in = (unsigned short*) inb;
^~~~~~~~~~~~~~~~~~~~~
encoding.c:815:27: warning: cast from 'unsigned char *' to 'unsigned short *' increases required alignment from 1 to 2 [-Wcast-align]
unsigned short* out = (unsigned short*) outb;
^~~~~~~~~~~~~~~~~~~~~~
4 warnings generated.
CC error.lo
CC parserInternals.lo
CC parser.lo
CC tree.lo
CC hash.lo
CC list.lo
CC xmlIO.lo
xmlIO.c:1450:52: error: use of undeclared identifier 'LZMA_OK'
ret = (__libxml2_xzclose((xzFile) context) == LZMA_OK ) ? 0 : -1;
^
1 error generated.
make[2]: *** [xmlIO.lo] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
========================================================================
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/Users/yourname/.rvm/rubies/ruby-2.4.1/bin/$(RUBY_BASE_NAME)
--help
--clean
--use-system-libraries
--enable-static
--disable-static
--with-zlib-dir
--without-zlib-dir
--with-zlib-include
--without-zlib-include=${zlib-dir}/include
--with-zlib-lib
--without-zlib-lib=${zlib-dir}/lib
--enable-cross-build
--disable-cross-build
/Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:400:in `block in execute': Failed to complete
compile task (RuntimeError)
from /Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:371:in `chdir'
from /Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:371:in `execute'
from /Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:114:in `compile'
from /Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:153:in `cook'
from extconf.rb:365:in `block (2 levels) in process_recipe'
from extconf.rb:257:in `block in chdir_for_build'
from extconf.rb:256:in `chdir'
from extconf.rb:256:in `chdir_for_build'
from extconf.rb:364:in `block in process_recipe'
from extconf.rb:262:in `tap'
from extconf.rb:262:in `process_recipe'
from extconf.rb:548:in `'
To see why this extension failed to compile, please check the mkmf.log which can be found here:
/Users/yourname/.rvm/gems/ruby-2.4.1@my-web/extensions/x86_64-darwin-15/2.4.0/nokogiri-1.8.0/mkmf.log
extconf failed, exit code 1
Gem files will remain installed in /Users/yourname/.rvm/gems/ruby-2.4.1@my-web/gems/nokogiri-1.8.0 for inspection.
Results logged to /Users/yourname/.rvm/gems/ruby-2.4.1@my-web/extensions/x86_64-darwin-15/2.4.0/nokogiri-1.8.0/gem_make.out
An error occurred while installing nokogiri (1.8.0), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.8.0'` succeeds before bundling.
In Gemfile:
rails was resolved to 5.1.3, which depends on
actioncable was resolved to 5.1.3, which depends on
actionpack was resolved to 5.1.3, which depends on
actionview was resolved to 5.1.3, which depends on
rails-dom-testing was resolved to 2.0.3, which depends on
nokogiri
ERROR: cannot discover where libxml2 is located on your system. please make sure `pkg-config` is installed.
nokogiri Requires libxml2, libxslt, and libiconv
It seems that nokogiri installation was failing because the three essential libraries libxml2, libxslt, and libiconv weren’t installed on macOS.
Let’s install them with brew install without thinking too much about it.
brew install libxml2 libxslt libiconv
After installation, let’s create symbolic links to the installed lib* with brew link —force.
brew link --force libxml2
brew link --force libxslt
brew link --force libiconv
Finally, enable the setting to build using the system libraries installed on macOS and run bundle install again to complete the process.
bundle config build.nokogiri --use-system-libraries
bundle install
Having to handle errors like this during Rails installation is subtly troublesome, which makes the momentum for Dockerizing development environments grow stronger.
That’s all from the Gemba.