bug#66885: 29.1; gnus search with mu always returns empty

[Britt Anderson <britt@uwaterloo.ca>]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> Your configuration looks correct (your configuration also reveals an
> annoying redundancy in gnus-search, which is that most nnmail
> backends have a "directory" value that can and should be used as the
> value of remove-prefix).
>
> Basically, if you're seeing "a maildir "y2023" that lives in archives"
> as a Gnus group, then this is just a bug in gnus-search's mu handling,
> plain and simple.

I think the bug starts on line 1952 of gnus-search.el.gz (when opened in
emacs). It is in the definition of the method for

~ cl-defmethod gnus-search-indexed-search-command ((engine
gnus-search-mu) ... ~

And the lines are:

	,@(if groups
	      `("and" "("
		,@(nbutlast (mapcan (lambda (x)
				      (list (concat "maildir:/" x) "or"))
				    groups))
		")")
	    "")


This splices the groups to be searched into the mu find query, but they
seem to mess up the search when put in there (at least the way I have mu
configured). When I comment out the offending lines above and recompile,
I can now search from withing gnus using G G. I noticed that this same
code for groups appears in the "grep" search that follows the mu method,
but did not appear in the method definitions above (including notmuch,
which also relies on xapian under the hood I believe) so I decided to
try the change.

Hope this information proves useful.

/Britt