如何卸载Nokogiri

Question

我正在尝试使用以下命令在我的系统上安装Rails：

gem install rails

但是我得到了这个错误：

Sams-MacBook-Pro-2:/ sammy$ gem install rails
Building native extensions.  This could take a while...
ERROR:  Error installing rails:
  ERROR: Failed to build gem native extension.

    current directory: /Users/sammy/.rvm/gems/ruby-2.4.1/gems/nokogiri-1.8.0/ext/nokogiri
/Users/sammy/.rvm/rubies/ruby-2.4.1/bin/ruby -r ./siteconf20170716-20185-7bepnp.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-darwin16.0.0/ports/libxml2/2.9.4... OK
Running git apply with /Users/sammy/.rvm/gems/ruby-2.4.1/gems/nokogiri-1.8.0/patches/libxml2/0001-Fix-comparison-with-root-node-in-xmlXPathCmpNodes.patch... OK
Running git apply with /Users/sammy/.rvm/gems/ruby-2.4.1/gems/nokogiri-1.8.0/patches/libxml2/0002-Fix-XPointer-paths-beginning-with-range-to.patch... OK
Running git apply with /Users/sammy/.rvm/gems/ruby-2.4.1/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/sammy/.rvm/gems/ruby-2.4.1/gems/nokogiri-1.8.0/ext/nokogiri/tmp/x86_64-apple-darwin16.0.0/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/sammy/.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/sammy/.rvm/rubies/ruby-2.4.1/lib/ruby/gems/2.4.0/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/sammy/.rvm/rubies/ruby-2.4.1/lib/ruby/gems/2.4.0/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:371:in `chdir'
  from /Users/sammy/.rvm/rubies/ruby-2.4.1/lib/ruby/gems/2.4.0/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:371:in `execute'
  from /Users/sammy/.rvm/rubies/ruby-2.4.1/lib/ruby/gems/2.4.0/gems/mini_portile2-2.2.0/lib/mini_portile2/mini_portile.rb:114:in `compile'
  from /Users/sammy/.rvm/rubies/ruby-2.4.1/lib/ruby/gems/2.4.0/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 `<main>'

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Users/sammy/.rvm/gems/ruby-2.4.1/extensions/x86_64-darwin-16/2.4.0/nokogiri-1.8.0/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /Users/sammy/.rvm/gems/ruby-2.4.1/gems/nokogiri-1.8.0 for inspection.
Results logged to /Users/sammy/.rvm/gems/ruby-2.4.1/extensions/x86_64-darwin-16/2.4.0/nokogiri-1.8.0/gem_make.out

我尝试使用以下命令卸载Nokogiri：

gem uninstall nokogiri

然后重新运行：

gem install rails

但是我得到了同样的错误。

我甚至尝试查找并删除其中包含"nokogiri“的每个目录，然后重新运行命令，得到相同的错误。

为什么Nokogiri不会消失？

Answer 1

您的问题不在于卸载Nokogiri，而在于安装它。Rails需要Nokogiri才能工作，但您的系统上可能缺少所需的库，因此无法安装nokogiri。您也可能在您的系统上安装了一个不稳定的库，导致扩展编译失败。

我根据您的错误日志进行了快速搜索，发现了这个问题：https://github.com/sparklemotion/nokogiri/issues/1483，但是，它可能与您遇到的问题相同，也可能不同，但它值得一查。

该问题的解决方案是卸载xz包。

brew uninstall xz

Answer 2

请阅读Nokogiri安装教程，其中明确解决了您报告的问题：

tutorials