Re: xref-find-references returns duplicates

[Dmitry Gutov]

On 19/12/2022 02:25, Petteri Hintsanen wrote:
> Hello list,
>
> I discovered a somewhat peculiar case where xref-find-references returns 
> duplicate references for elisp symbols.
>
> Here is a toy example:
>
> 1. Create a file ~/foo/bar/bar.el with contents:
>
>    (defun bar-f ())
>
>    (defun bar-g ()
>      (bar-f))
>
>    (provide 'bar)
>
> 2. Create a git repo in ~/foo/bar and commit bar.el.  This is just to 
> set up a project that Emacs can recognize.
>
> 3. Start emacs -Q and eval
>
>    (add-to-list 'load-path "~/foo")
>    (add-to-list 'load-path "~/foo/bar")
>    (require 'bar)
>
> 4. Visit ~/foo/bar/bar.el and do xref-find-references for bar-f
>
> On my machine I get
>
>    bar.el
>    1: (defun bar-f ())
>    4:   (bar-f))
>    1: (defun bar-f ())
>    4:   (bar-f))
>
> i.e. references are duplicated.  The issue seems to be in load-path: if 
> I remove ~/foo from step (3) above, then I don't see any duplicates.
>
> Am I abusing load-path somehow, or is this a bug, or something else?

I suppose it's a bug, or a limitation of the algorithm anyway.

The default "find references" implementation currently delegates to 
xref-references-in-directory, which uses the semantic-symref-tool 
facility to search for a simple notion of "references" inside a 
directory tree. It doesn't have a mechanism to exclude certain 
directories, such as the current project root (from being searched twice 
over).

You can file a bug report with 'M-x report-emacs-bug', different ways to 
solve this exist, more or less adequately.