bug#48471: 28.0.50; Incorrect handling of `project-ignores' on macOS (BSD find?) if project root is a directory name

[Dmitry Gutov <dgutov@yandex.ru>]

On 23.05.2021 14:08, Philipp wrote:
>> though it would be better to use a version of it which fixes the same behavior in two other related functions as well. The previous patch for that approach is here:https://lists.gnu.org/archive/html/emacs-devel/2021-01/txtDduOxGoiGz.txt
>>
>> (From the messagehttps://lists.gnu.org/archive/html/emacs-devel/2021-01/msg00345.html).
>>
>> Also, since it will fix the double-slash problem, we can undo the change from 331e40a8fd491ceb35c08a3345785dab61bc60d9, the one that made our comparisons lax (to match both single and double slashes).
> I'm also fine with either of those, but we should first make sure that the code in question is well-covered by unit tests to avoid regressions.

Tests are good to have, yes.

Speaking of the implementation, any chance we would want to have "-H" 
inside grep-find-template by default?

Has that been considered in the past perhaps? Eli, Lars, Stefan?

The simplest change to that effect should look like this:

diff --git a/lisp/progmodes/grep.el b/lisp/progmodes/grep.el
index e9fbcbbfcd..9956ba79d0 100644
--- a/lisp/progmodes/grep.el
+++ b/lisp/progmodes/grep.el
@@ -777,19 +777,19 @@ grep-compute-defaults
  				(format "%s " (null-device))
  			      "")))
  		  (cond ((eq grep-find-use-xargs 'gnu)
-			 (format "%s <D> <X> -type f <F> -print0 | \"%s\" -0 %s"
+			 (format "%s -H <D> <X> -type f <F> -print0 | \"%s\" -0 %s"
  				 find-program xargs-program gcmd))
  			((eq grep-find-use-xargs 'gnu-sort)
-			 (format "%s <D> <X> -type f <F> -print0 | sort -z | \"%s\" -0 %s"
+			 (format "%s -H <D> <X> -type f <F> -print0 | sort -z | \"%s\" -0 %s"
  				 find-program xargs-program gcmd))
  			((eq grep-find-use-xargs 'exec)
-			 (format "%s <D> <X> -type f <F> -exec %s %s %s%s"
+			 (format "%s -H <D> <X> -type f <F> -exec %s %s %s%s"
  				 find-program gcmd quot-braces null quot-scolon))
  			((eq grep-find-use-xargs 'exec-plus)
-			 (format "%s <D> <X> -type f <F> -exec %s %s%s +"
+			 (format "%s -H <D> <X> -type f <F> -exec %s %s%s +"
  				 find-program gcmd null quot-braces))
  			(t
-			 (format "%s <D> <X> -type f <F> -print | \"%s\" %s"
+			 (format "%s -H <D> <X> -type f <F> -print | \"%s\" %s"
  				 find-program xargs-program gcmd))))))))

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