Load a large TAGS file from a remote host at a Windows machine

Question

I run Emacs locally on my Windows machine, but edit everything remotely, via tramp & plink (PuTTY's implementation of ssh). This all works just fine, but, as I found out today, TAGS files for large projects do not work. It's not that these files are that large - 12 Mb, in my case, a few thousand .cpp files, but still.

 

If I load TAGS file with visit-tags-table remotely, with /plink:user@host:/home/user/project/TAGS path, my Emacs just hangs forever, eating 100% of one of the CPU cores. It does not happen for smaller files, these work just fine, but for larger ones in happened every time I tried.

If I load it remotely, but with pscp, /pscp:user@host:/home/user/project/TAGS, it just does not load, tags-apropos shows no tags loaded.

If I copy the TAGS file to my local machine, visit-tags-table load tags just fine, but when I use them, Emacs expects the files mentioned there to be where the TAGS file is, i.e. on my local machine. If I generate TAGS with relative paths, it would try to open c:/emacs/home/path/file.h, if I use --tag-relative=no when generating TAGS to obtain absolute paths, the path changes to c:/home/user/project/path/file.h.

 

Of these three fails the last one looks the most 'fixable' (for the first two I suspect some shady network configuration issues), but I have yet to find how to make a local TAGS file work for remote projects.

Dirty hacks like changing all paths in TAGS with sed from /home/... to /plink:user@host:/home/... don't work, I tried (Emacs just tries to open c:/plink!user@host!/home/... file in this case).

In this question someone offered rewriting a etags-file-of-tag function from etags.el - this looks promising, but that does not work for me either (either this is a wrong function, or I'm doing something very wrong: no matter how I change that one, it doesn't seem to affect anything). Unfortunately, I have a quite limited understanding of elisp and how Emacs works in general, so I am stuck at the moment.

 

I really want TAGS to work for this project, so any ideas or advice will be appreciated.

Answer 1

create multiple smaller TAGS in sub-directory instead of one big TAGS in root directory,

insert below code into ~/.emacs,

(setq tags-table-list "~/proj/sub-dir1/TAGS" "~/proj/sub-dir2/TAGS")

That's all you need to do.

BTW, I don't like visit-tags-table which basically just (setq tags-file-name "~/proj/TAGS"). To use tags-table-list, tags-file-name should be nil.