xref-find-definitions with multiple active projects
reddit / emacs

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mgulick · 2022-10-19 21:39

I'm not an emacs power user nor very proficient at elisp.

I use magit quite heavily in emacs, and I'm regularly working on
multiple git repositories at the same time.  These are different
repositories/worktrees for the same project, just with different
branches checked out.  I'm not sure if it is relevant, but these are
Perl projects, using cperl-mode, and each project has a single TAGS
files at the project root.  The first time I use \`M-.\` (\`xref-find-
definitions\`), I get prompted to load a TAGS file, and I select the
one for the current repository I'm using.  This works as expected.
However when I happen to be editing a file from a different repository
and hit M-., the previously loaded TAGS file is still used, so this
brings me to the source file from the wrong repository.  Since the
files look identical, I don't notice this and regularly make edits in
the wrong git worktree.

I saw that I can load multiple tags tables using visit-tags-table, and
then switch between them using select-tags-table.  Is there any way to
automate this so that when I use \`M-.\` it automatically chooses the
TAGS file closest to the current file path?  I looked into project.el
and projectile, but I couldn't find any examples for how to do this.

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redguardtoo · 2022-10-19 22:38

https://github.com/redguardtoo/counsel-etags , it automatically picks
up right tags per project.

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hvis · 2022-10-20 13:14

I suspect it will require a different xref backend, or a modification
of the existing one.

Someone could monkeypatch that with third-party code, but `M-x report-
emacs-bug` might get you there as well.

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mgulick · 2022-10-20 13:28

Thanks for the suggestion.  I gave this a try, but I couldn't get it
to pick up the existing TAGS files.  It kept falling back to a grep.
I also didn't see a way to jump to the definition of a function.  It
looks like it was just searching for references, which you then need
to wade through to find which one is the definition.

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redguardtoo · 2022-10-20 22:27

It automatically detects the TAGS in project root folder.

It falls back to grep if the definition does not exist in TAGS. So you
need check TAGS.

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FreeAd7233 · 2022-10-24 09:41

Give citre a try. Citre picks up tags depending on the project root
automatically, and provides you find definitions and completions
easily (and even references if using gnu global)