(Info-directory-list): Revert change to re-writing

Info-default-directory-list, but put `alternative' first.
(Info-insert-dir): Modify selecting the top dir file as a
consequence.

1 files changed, 11 insertions, 15 deletions

diff --git a/lisp/info.el b/lisp/info.el
index a6acbe512c2..0deffb71bda 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -87,8 +87,8 @@ The Lisp code is executed when the node is selected.")
     (if path
         (split-string path (regexp-quote path-separator))
       (if (and sibling (file-exists-p sibling))
-          (setq alternative sibling)
-        (setq alternative source))
+          (setq alternative sibling)    ; uninstalled, Emacs builddir != srcdir
+        (setq alternative source))      ; uninstalled, builddir != srcdir
       (if (or (member alternative Info-default-directory-list)
               (not (file-exists-p alternative))
               ;; On DOS/NT, we use movable executables always,
@@ -101,16 +101,11 @@ The Lisp code is executed when the node is selected.")
                               (expand-file-name "lib-src/"
                                                 installation-directory)))))
           Info-default-directory-list
-        ;; Substitute the alternative for occurences of the
-        ;; installation directory.  The latter occurs last, but maybe
-        ;; more than once, so that it overrides /usr/info in
-        ;; particular.
-        (let ((instdir (car (last Info-default-directory-list))))
-          (mapcar (lambda (dir)
-                    (if (string= dir instdir)
-                        alternative
-                      dir))
-                  Info-default-directory-list)))))
+        ;; `alternative' contains the Info files that came with this
+        ;; version, so we should look there first.  `Info-insert-dir'
+        ;; currently expects to find `alternative' first on the list.
+        (cons alternative
+              (reverse (cdr (reverse Info-default-directory-list)))))))
   "List of directories to search for Info documentation files.
 nil means not yet initialized.  In this case, Info uses the environment
 variable INFOPATH to initialize it, or `Info-default-directory-list'
@@ -648,9 +643,10 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
           (error "Can't find the Info directory node"))
       ;; Distinguish the dir file that comes with Emacs from all the
       ;; others.  Yes, that is really what this is supposed to do.
-      ;; If it doesn't work, fix it.
-      (setq buffer (car buffers)
-            others (cdr buffers))
+      ;; The definition of `Info-directory-list' puts it first on that
+      ;; list and so last in `buffers' at this point.
+      (setq buffer (car (last buffers))
+            others (delq buffer buffers))
 
       ;; Insert the entire original dir file as a start; note that we've
       ;; already saved its default directory to use as the default