bug#5928: grep.el: Incorrect processing of host-default settings in grep-compute-defaults

[Christoph]

grep.el, bzr revision 99871, line 515:

(set setting
     (or (cadr (assq setting host-defaults))
         (cadr (assq setting defaults)))))

Value of host-defaults can be nil, e.g. for grep-use-null-device. In 
this case, cadr returns nil and the other branch of the or is executed, 
assigning the value from defaults to the setting and effectively 
discarding the value from host-defaults.

The following patch fixes this issue:

=== modified file 'lisp/progmodes/grep.el'
--- lisp/progmodes/grep.el      2010-01-31 21:47:47 +0000
+++ lisp/progmodes/grep.el      2010-04-08 00:11:28 +0000
@@ -513,8 +513,8 @@
                       grep-find-template grep-find-use-xargs
                       grep-highlight-matches))
       (set setting
-          (or (cadr (assq setting host-defaults))
-              (cadr (assq setting defaults)))))
+          (cadr (or (assq setting host-defaults)
+                    (assq setting defaults)))))

     (unless (or (not grep-use-null-device) (eq grep-use-null-device t))
       (setq grep-use-null-device