Include vendor's tags for ruby-mode and ggtags

Question

I'm trying to install and configure the ggtags package. Primarily, I use it for a ruby on rails projects (enh-ruby-mode).

I can generate ctags including all vendor's files for my project with the following command:

ctags -R --languages=ruby --exclude=.git --exclude=log . $(bundle list --paths)

How can I configure ggtags package to achieve the same thing?

I use OS X, with installed exuberant-ctags and pygments plugins.

I think, I need to add some settings to ~/.globalrc or to the project root's gtags.conf, but I don't know the settings.

Answer 1

Here's how to use global installed from a Ubuntu repository. The version I've had in 6.6.3-2.

First, copy the example config to your home directory. A commentary at its top makes it seem like this is unnecessary, but that's not true. The default config it has is much different, and doesn't recognize .rb files at all, AFAICT.

cat /usr/share/doc/global/examples/gtags.conf.gz | gzip -d >~/.globalrc

Second, you need to choose the underlying mechanism. Pygments sounds great, but it generates "other symbol" entries, not definitions, which is what we normally need.

universal-ctags might be the best choice, but the version of Global seems to need recompiling to use it (either the apt or the snap version). exuberant-ctags works out of the box, though. The ancient version 5.9~svn20110310-1.

Now, as explained in the documentation and in this issue, you would normally need to run gtags --gtagslabel= in every gem directory:

for d in $(bundle list --paths); do
    if [ -d $d ]; then
        echo "$d";
        (cd $d && find . -type f -name "*.rb" | gtags --gtagslabel=ctags -f -)
    fi
done

The use of find here is to avoid including JS files, etc, mostly because of the minified assets. But you can create a smarter enumeration.

To use the indexes from all these directories you need to set the env var GTAGSLIBPATH to the appropriate value during an Emacs session. Given that it's different for every project, and even changes over time, maybe the best approach is to manually call a command in the project directory that will do that for you. Here's one you can use:

(defun set-gtagslibpath-to-bundle-paths ()
  (interactive)
  (let ((paths
         (split-string
          (with-output-to-string
            (process-file-shell-command "bundle list --paths" nil
                                        standard-output))
          "\n")))
    (while (and paths
                (string-match-p "\\`The dependency'" (car paths)))
      (setq paths (cdr paths)))
    (setenv "GTAGSLIBPATH"
            (mapconcat #'identity paths ":"))))

Answer 2

You can also generate the tags with the following command to command to be read by ggtags

gtags --gtagslabel=ctags

The above command should be helpful of any language not supported by gtags but supported by ctags.