Problems installing Nokogiri (1.5.2) on Ubuntu 12.10 - ruby

Question

I'm running Ubuntu 12.10, and, when I run the command:
bundle install
I get:
Installing nokogiri (1.5.2) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
/usr/bin/ruby1.9.1 extconf.rb
extconf.rb:10: Use RbConfig instead of obsolete and deprecated Config.
checking for libxml/parser.h... yes
checking for libxslt/xslt.h... yes
checking for libexslt/exslt.h... yes
checking for iconv_open() in iconv.h... yes
checking for xmlParseDoc() in -lxml2... yes
checking for xsltParseStylesheetDoc() in -lxslt... yes
checking for exsltFuncRegister() in -lexslt... yes
checking for xmlHasFeature()... yes
checking for xmlFirstElementChild()... yes
checking for xmlRelaxNGSetParserStructuredErrors()... yes
checking for xmlRelaxNGSetParserStructuredErrors()... yes
checking for xmlRelaxNGSetValidStructuredErrors()... yes
checking for xmlSchemaSetValidStructuredErrors()... yes
checking for xmlSchemaSetParserStructuredErrors()... yes
creating Makefile
make
compiling xml_processing_instruction.c
compiling xml_node.c
compiling html_entity_lookup.c
compiling xml_syntax_error.c
compiling xml_document.c
xml_document.c: In function ‘set_encoding’:
xml_document.c:159:12: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
xml_document.c: In function ‘canonicalize’:
xml_document.c:505:15: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
compiling xml_encoding_handler.c
compiling xml_namespace.c
xml_namespace.c: In function ‘prefix’:
xml_namespace.c:14:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
xml_namespace.c: In function ‘href’:
xml_namespace.c:33:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
compiling xml_entity_decl.c
compiling xml_attribute_decl.c
compiling xml_comment.c
compiling xml_dtd.c
compiling xml_xpath_context.c
xml_xpath_context.c: In function ‘xpath_generic_exception_handler’:
xml_xpath_context.c:189:3: error: format not a string literal and no format arguments [-Werror=format-security]
cc1: some warnings being treated as errors
make: *** [xml_xpath_context.o] Error 1
Gem files will remain installed in /home/site/.bundler/tmp/19240/gems/nokogiri-1.5.2 for inspection.
Results logged to /home/site/.bundler/tmp/19240/gems/nokogiri-1.5.2/ext/nokogiri/gem_make.out
An error occured while installing nokogiri (1.5.2), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.5.2'` succeeds before bundling.
When I run:
gem install nokogiri -v '1.5.2'
I get:
site#ubuntu:~/Documents/shopqi$ gem install nokogiri -v '1.5.2'
malloc_limit=60000000 (8000000)
free_min=50000 (4096)
Building native extensions. This could take a while...
Successfully installed nokogiri-1.5.2
1 gem installed
Installing ri documentation for nokogiri-1.5.2...
Installing RDoc documentation for nokogiri-1.5.2...
site#ubuntu:~/Documents/shopqi$
There's no error, but if I try bundle install again I get the error that Nokogiri is not installed.
the content of gem_make.out after running sudo gem install nokogiri -v '1.5.2' is:
/usr/bin/ruby1.9.1 extconf.rb
extconf.rb:10: Use RbConfig instead of obsolete and deprecated Config.
checking for libxml/parser.h... yes
checking for libxslt/xslt.h... yes
checking for libexslt/exslt.h... yes
checking for iconv_open() in iconv.h... yes
checking for xmlParseDoc() in -lxml2... yes
checking for xsltParseStylesheetDoc() in -lxslt... yes
checking for exsltFuncRegister() in -lexslt... yes
checking for xmlHasFeature()... yes
checking for xmlFirstElementChild()... yes
checking for xmlRelaxNGSetParserStructuredErrors()... yes
checking for xmlRelaxNGSetParserStructuredErrors()... yes
checking for xmlRelaxNGSetValidStructuredErrors()... yes
checking for xmlSchemaSetValidStructuredErrors()... yes
checking for xmlSchemaSetParserStructuredErrors()... yes
creating Makefile
make
compiling xml_processing_instruction.c
compiling xml_node.c
compiling html_entity_lookup.c
compiling xml_syntax_error.c
compiling xml_document.c
xml_document.c: In function ‘set_encoding’:
xml_document.c:159:12: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
xml_document.c: In function ‘canonicalize’:
xml_document.c:505:15: warning: cast discards ‘__attribute__((const))’ qualifier from pointer target type [-Wcast-qual]
compiling xml_encoding_handler.c
compiling xml_namespace.c
xml_namespace.c: In function ‘prefix’:
xml_namespace.c:14:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
xml_namespace.c: In function ‘href’:
xml_namespace.c:33:13: warning: variable ‘doc’ set but not used [-Wunused-but-set-variable]
compiling xml_entity_decl.c
compiling xml_attribute_decl.c
compiling xml_comment.c
compiling xml_dtd.c
compiling xml_xpath_context.c
xml_xpath_context.c: In function ‘xpath_generic_exception_handler’:
xml_xpath_context.c:189:3: error: format not a string literal and no format arguments [-Werror=format-security]
cc1: some warnings being treated as errors
make: *** [xml_xpath_context.o] Error 1
Any help please?

Answer 1

Try this first:
$ apt-get install libxml2-dev libxslt1-dev
Also, if you're using rvm, do:
$ rvm requirements

Answer 2

Ubuntu 12.10 adopts Debian's hardening wrapper, which includes a set of default flags for GCC that cause this compilation error. We've worked around this in Nokogiri 1.5.4 and higher, so you'll need to either upgrade or find your own workaround.
See here for information on Debian hardening.
See here for details on the solution used by Team Nokogiri.