elisp: Add and use 'guix-file-name'

Various Guix (Guile) procedures are sensitive to "non-expanded" file
names and to trailing slashes in directory names, so
'directory-file-name' and 'expand-file-name' are called here and there.
Make a single function to fix it once and for all.

* elisp/guix-utils.el (guix-file-name): New function.
* elisp/guix-hash.el (guix-hash): Use it.
* elisp/guix-profiles.el (guix-profile): Use it.
* elisp/guix-misc.el (guix-apply-manifest): Use it.
* elisp/guix-repl.el (guix-repl-guile-args): Use it.
* elisp/guix-ui.el (guix-ui-buffer-name-short): Use it.
* elisp/guix-ui-profile.el (guix-profiles): Use it.
* elisp/guix-ui-generation.el
(guix-generation-packages-buffer-name-default): Use it.

elisp/guix-hash.el

@@ -48,7 +48,7 @@ See also Info node `(guix) Invoking guix hash'."
    (list (guix-read-file-name-maybe)
          (and current-prefix-arg
               (guix-read-hash-format))))
-  (let* ((file (expand-file-name file))
+  (let* ((file (guix-file-name file))
          (args (list :format (or format guix-default-hash-format)))
          (args (if (file-directory-p file)
                    (append '(:recursive? t) args)
@@ -58,7 +58,7 @@ See also Info node `(guix) Invoking guix hash'."
                        'file-hash file args))))
     (kill-new hash)
     (message "Hash of \"%s\" (%s) has been added to the kill ring."
-             (file-name-nondirectory (directory-file-name file))
+             (file-name-nondirectory file)
              hash)))
 
 (provide 'guix-hash)

elisp/guix-misc.el

@@ -183,8 +183,8 @@ FILE.  With a prefix argument, also prompt for PROFILE."
      (guix-make-guile-expression
       'guix-command
       "package"
-      (concat "--profile="  (expand-file-name profile))
-      (concat "--manifest=" (expand-file-name file)))
+      (concat "--profile="  (guix-file-name profile))
+      (concat "--manifest=" (guix-file-name file)))
      operation-buffer)))
 
 (defcustom guix-search-paths-buffer-name "*Guix Search Paths*"

elisp/guix-profiles.el

@@ -112,7 +112,7 @@ have a trailing slash and it is `guix-default-profile' if PROFILE
 is `guix-user-profile'.  `guix-user-profile' is special because
 it is actually a symlink to a real user profile, and the HOME
 directory does not contain profile generations."
-  (let ((profile (directory-file-name (expand-file-name profile))))
+  (let ((profile (guix-file-name profile)))
     (if (string= profile guix-user-profile)
         guix-default-profile
       profile)))

elisp/guix-repl.el

@@ -225,8 +225,8 @@ See `guix-emacs-activate-after-operation' for details."
                   (lcp (if guix-load-compiled-path
                            (guix-list-maybe guix-load-compiled-path)
                          lp)))
-             (append (--mapcat (list "-L" (expand-file-name it)) lp)
-                     (--mapcat (list "-C" (expand-file-name it)) lcp))))
+             (append (--mapcat (list "-L" (guix-file-name it)) lp)
+                     (--mapcat (list "-C" (guix-file-name it)) lcp))))
     "-L" ,guix-scheme-directory
     ,@(and guix-config-scheme-compiled-directory
            (list "-C" guix-config-scheme-compiled-directory))

elisp/guix-ui-generation.el

@@ -491,7 +491,7 @@ and its store file name."
 (defun guix-generation-packages-buffer-name-default (profile generation)
   "Return name of a buffer for displaying GENERATION's package outputs.
 Use base name of PROFILE file name."
-  (let ((profile-name (file-name-base (directory-file-name profile))))
+  (let ((profile-name (file-name-base (guix-file-name profile))))
     (format "*Guix %s: generation %s*"
             profile-name generation)))
 

elisp/guix-ui-profile.el

@@ -49,7 +49,7 @@
                    guix-system-profile
                    guix-pulled-profile
                    (--when-let (getenv "GUIX_PROFILE")
-                     (expand-file-name it)))))
+                     (guix-file-name it)))))
   "List of profiles displayed by '\\[guix-profiles]' command."
   :type '(repeat file)
   :group 'guix-profile)

elisp/guix-ui.el

@@ -109,7 +109,7 @@ The function is called with 2 arguments: BASE-NAME and PROFILE."
 (defun guix-ui-buffer-name-short (base-name profile)
   "Return buffer name by appending BASE-NAME and PROFILE's base file name."
   (guix-compose-buffer-name base-name
-                            (file-name-base (directory-file-name profile))))
+                            (file-name-base (guix-file-name profile))))
 
 (defun guix-ui-buffer-name-full (base-name profile)
   "Return buffer name by appending BASE-NAME and PROFILE's full name."

elisp/guix-utils.el

@@ -289,6 +289,10 @@ If nil, always prompt for a file name."
   :type 'boolean
   :group 'guix)
 
+(defun guix-file-name (file-name)
+  "Expand FILE-NAME and remove trailing slash if needed."
+  (directory-file-name (expand-file-name file-name)))
+
 (defun guix-read-file-name (&optional prompt dir default-filename
                                       mustmatch initial predicate)
   "Read file name.