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Revision as of 01:31, 1 November 2008 by Mtasaka (talk | contribs) (→‎Example)

Proposal for package Ruby Gem including extension library written in C

Current status

Current packaging guidelines on Fedora about Ruby Gems are mainly written on https://fedoraproject.org/wiki/Packaging/Ruby#Ruby_Gems

The guideline says: 

The install should be performed with the command
$ gem install --local --install-dir %{buildroot}%{gemdir} --force %{SOURCE0}

Problem

This causes some problems especially when Ruby Gem contains extension libraries written in C because of the following reason.

A-1

First of all the above procedure will cause the error like following. 

+ /usr/lib/rpm/check-buildroot
Binary file /home/tasaka1/rpmbuild/INSTROOT/rubygem-zoom-0.4.1-4.fc9p-root-tasaka1/usr/lib/debug/usr/lib/ruby/site_ruby/1.8/i386-linux/zoom.so.debug matches
Found '/home/tasaka1/rpmbuild/INSTROOT/rubygem-zoom-0.4.1-4.fc9p-root-tasaka1' in installed files; aborting
error: Bad exit status from /home/tasaka1/rpmbuild/INSTROOT/rpm-tmp.84251 (%install)

This is because with above command:

  • gem first unpacks files in the gem file under %{buildroot}%{gemdir}
  • Then gem (actually gcc) compiles C source files installed under there.

So the rebuilt C library may contain %{buildroot} string.

A-2

So to avoid this error some maintainers on Fedora of rubygems including extension written in C simply strip compiled C libraries before %install stage ends.

  • Of course this won't create debuginfo file correctly.
  • Also, when Gem is directly installed under %{buildroot} and %prep is blank, find_debuginfo.sh won't be called anyway because %{buildsubdir} is not defined (this is because debugXXX.list can't be written when %{_builddir}/%{buildsubdir} is missing).

Solution to A

The problem written in A can be resolved when Ruby Gems are installed under %{_builddir} first.

B

Currently there is no mention about how to pass Fedora specific compilation flags correctly.

Solution to B

Usually ruby extension uses ruby script file named extconf.rb which has require 'mkmf'. mkmf.rb module accepts CONFIGURE_ARGS environment to specify CFLAGS so using this is preferred.

Proposition

When Ruby Gem contains extension libraries written in C,

  • First %{_builddir}/%{buildsubdir} must be created at %prep stage.
  • The following line should be used to pass CFLAGS to Makefile to be created correctly.
export CONFIGURE_ARGS="--with-cflags='%{optflags}'"
  • Then the Ruby Gem must be installed under %{_builddir}/%{buildsubdir} at %build stage to get C libraries compiled under the directory.
  • When using gem command to install Gem file, using -V option is recommend to check if CFLAGS is correctly honored.
  • Finally at %install stage the whole tree under %{_builddir}/%{buildsubdir}%{gemdir} should be copied (not moved) to under %{buildroot}%{gemdir}.
    • When all tree under %{_builddir}/%{buildsubdir} is moved to under %{buildroot}, find_debuginfo.sh will complain that the corresponding source files are missing.


Note

The current guideline 

If the Gem contains binary content (e.g., for a database driver), it must be marked 
as architecture specific, and all architecture specific content must be moved 
from the %{gemdir} to the [#ruby_sitearch %{ruby_sitearch} directory] during %install

must still apply.

Example

%prep
%setup -q -T -c

%build
mkdir -p ./%{gemdir}
export CONFIGURE_ARGS="--with-cflags='%{optflags}'"
gem install --local --install-dir ./%{gemdir} -V --force %{SOURCE0}

%install
rm -rf %{buildroot}
mkdir -p %{buildroot}%{gemdir}
cp -a ./%{gemdir}/* %{buildroot}%{gemdir}
....

Issues

Installed C codes

Currently all C codes (in Gem file) are also installed with gem install (usually under %{geminstdir}/ext). In my recognition these files are used only for creating C libraries and are not needed anymore. So actually some packagers simply remove these files.

  • Note that when also non-Gem type of source archive is provided, when using non-Gem version such C codes are usually not installed.

However Gem has its own metadata and Gem actually reports that these files should have been installed.

Example

  • Currently in rubygem-pam rpm no files are under %{geminstdir}/ext (on i386 this is currently /usr/lib/ruby/gems/1.8/gems/pam-1.5.3/ext).
  • However gem contents pam actually returns some files under this directory.

How should we treat these files?

  • simply don't remove these files
  • ignore gem report in this case and remove these anyway
  • seperate these files into subpackages (e.g. -source subpackage)
  • or anything else
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