bug#49978: 28.0.50; grep-highlight-matches auto-detection broken on macOS [PATCH]

["Mattias Engdegård" <mattiase@acm.org>]

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The auto-detection of colourised grep fails on macOS (and presumably BSD in general) because grep --help exits with a nonzero status (while still printing a useful option summary).

We should just ignore the exit status. Anyone against the attached patch?


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diff --git a/lisp/progmodes/grep.el b/lisp/progmodes/grep.el
index 8f0a5acf70..a33a247d9b 100644
--- a/lisp/progmodes/grep.el
+++ b/lisp/progmodes/grep.el
@@ -696,11 +696,11 @@ grep-compute-defaults
     (when (eq grep-highlight-matches 'auto-detect)
       (setq grep-highlight-matches
 	    (with-temp-buffer
-	      (and (grep-probe grep-program '(nil t nil "--help"))
-		   (progn
-		     (goto-char (point-min))
-		     (search-forward "--color" nil t))
-		   ;; Windows and DOS pipes fail `isatty' detection in Grep.
+              ;; The "grep --help" exit status varies; pay no attention to it.
+              (grep-probe grep-program '(nil t nil "--help"))
+	      (goto-char (point-min))
+	      (and (search-forward "--color" nil t)
+	           ;; Windows and DOS pipes fail `isatty' detection in Grep.
 		   (if (memq system-type '(windows-nt ms-dos))
 		       'always 'auto)))))