nixpkgs/pkgs/build-support/fetchgitrevision/default.nix

runCommand: git: repository: branch:
  import (runCommand "head-revision"
    { buildInputs = [ git ];
      dummy = builtins.currentTime;
    }
    ''
      rev=$(git ls-remote ${repository} | grep "refs/${branch}$" | awk '{ print $1 }')
      echo "[ \"$rev\" ]" > $out
      echo Latest revision in ${branch} is $rev
    '')
Live builds support: initially for git and svn. taglib_live is packaged as an example. svn path=/nixpkgs/trunk/; revision=25351 2011-01-02 23:23:59 +00:00			`runCommand: git: repository: branch:`
			`import (runCommand "head-revision"`
			`{ buildInputs = [ git ];`
			`dummy = builtins.currentTime;`
			`}`
			`''`
			`rev=$(git ls-remote ${repository} \| grep "refs/${branch}$" \| awk '{ print $1 }')`
			`echo "[ \"$rev\" ]" > $out`
			`echo Latest revision in ${branch} is $rev`
Remove semicolon causing evaluation error. svn path=/nixpkgs/trunk/; revision=25354 2011-01-02 23:52:39 +00:00			`'')`