[PATCH] Implement XDG Base Directory specification for user-emacs-directory (was: [Emacs-diffs] master d68ed15: Implement and document XDG-style startup files under ~/.config.)

[Amin Bandali <bandali@gnu.org>]

[-- Attachment #1: Type: text/plain, Size: 722 bytes --]

Hello,

Eli Zaretskii <eliz@gnu.org> writes:

[...]

>
> No response in a week.
>
> Would someone like to suggest changes to fix the problems in this
> commit?  If so, please show the proposed changes, and let's discuss
> them.  Failing that, I will revert that commit in a couple of days.
>
>

I’ve attached my first try at this.  At first it was only concerned with
lisp/startup.el—like ESR’s change—but then I thought it would be even
nicer to do it at the user-emacs-directory itself.  It’s not quite there
yet—as it tries to use things in lisp/subr.el before they’re actually
defined/loaded—but it lays out what I have in mind.

Feedback and help appreciated.

Thanks,
amin


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Implement-XDG-Base-Directory-specification-for-user-.patch --]
[-- Type: text/x-patch, Size: 10863 bytes --]

From 4d66998bff5de197e097870c30cc0b533bc134ac Mon Sep 17 00:00:00 2001
From: Amin Bandali <bandali@gnu.org>
Date: Sun, 9 Jun 2019 02:29:52 -0400
Subject: [PATCH] Implement XDG Base Directory specification for
 user-emacs-directory

* lisp/startup.el (command-line): Use user-emacs-directory instead of
  hard-coding "~/.emacs.d".

* lisp/subr.el (user-emacs-directory): Use "$XDG_CONFIG_HOME/emacs/"
  if XDG_CONFIG_HOME is set and has an "emacs/" subdirectory.
  Otherwise, try "~/.config/emacs/" before falling back to
  "~/.emacs.d/".
---
 doc/emacs/custom.texi | 72 +++++++++++++++++++++++--------------------
 etc/NEWS              |  6 ++++
 lisp/startup.el       | 19 +++---------
 lisp/subr.el          |  6 +++-
 4 files changed, 54 insertions(+), 49 deletions(-)

diff --git a/doc/emacs/custom.texi b/doc/emacs/custom.texi
index 982cea1f21..b582601cae 100644
--- a/doc/emacs/custom.texi
+++ b/doc/emacs/custom.texi
@@ -380,7 +380,7 @@ Saving Customizations
 file.  For example:
 
 @example
-(setq custom-file "~/.config/emacs-custom.el")
+(setq custom-file "~/.config/emacs/custom.el")
 (load custom-file)
 @end example
 
@@ -390,14 +390,14 @@ Saving Customizations
 @example
 (cond ((< emacs-major-version 22)
        ;; @r{Emacs 21 customization.}
-       (setq custom-file "~/.config/custom-21.el"))
+       (setq custom-file "~/.config/emacs/custom-21.el"))
       ((and (= emacs-major-version 22)
             (< emacs-minor-version 3))
        ;; @r{Emacs 22 customization, before version 22.3.}
-       (setq custom-file "~/.config/custom-22.el"))
+       (setq custom-file "~/.config/emacs/custom-22.el"))
       (t
        ;; @r{Emacs version 22.3 or later.}
-       (setq custom-file "~/.config/emacs-custom.el")))
+       (setq custom-file "~/.config/emacs/custom.el")))
 
 (load custom-file)
 @end example
@@ -2215,28 +2215,30 @@ Init File
 @cindex init file
 @cindex .emacs file
 @cindex ~/.emacs file
-@cindex ~/.config/emacs file
+@cindex ~/.config/emacs/init.el file
 @cindex Emacs initialization file
 @cindex startup (init file)
 
   When Emacs is started, it normally tries to load a Lisp program from
 an @dfn{initialization file}, or @dfn{init file} for short.  This
 file, if it exists, specifies how to initialize Emacs for you.  Emacs
-looks for your init file using the filenames
-@file{~/.config/emacs},. @file{~/.emacs}, @file{~/.config/emacs.el},
-@file{~/.emacs.el}, @file{~/.config/emacs.d/init.el} or
-@file{~/.emacs.d/init.el}; you can choose to use any one of these
-names (@pxref{Find Init}).  Here, @file{~/} stands for your home
-directory.
+looks for your init file using the filenames @file{~/.emacs} or
+@file{~/.emacs.el}.  Here, @file{~/} stands for your home directory.
+Alternatively, you may wish to group all things Emacs-related in one
+place in the Emacs configuration directory.  Emacs looks for
+@file{$XDG_CONFIG_HOME/emacs/init.el}, using @file{~/.config} for
+@env{XDG_CONFIG_HOME} if it's not set.  If
+@file{$XDG_CONFIG_HOME/emacs/} doesn't exist, Emacs will fall back to
+@file{~/.emacs.d/} and look for @file{~/.emacs.d/init.el} instead
+(@pxref{Find Init}).
 
   While the @file{~/.emacs} and @file{~/.emacs.d/init.el} locations
 are backward-compatible to older Emacs versions, and the rest of this
-chapter will use them to name your initialization file, it is better practice
-to group all of your dotfiles under @file{.config} so that if you have
-to troubleshoot a problem that might be due to a bad init file, or
-archive a collection of them, it can be done by renaming or
-copying that directory.  Note that the @file{.config} versions
-don't have a leading dot on the basename part of the file.
+chapter will use them to name your initialization file, it is better
+practice to group all of your dotfiles under @file{~/.config} so that
+if you have to troubleshoot a problem that might be due to a bad init
+file, or archive a collection of them, it can be done by renaming or
+copying that directory.
 
   You can use the command line switch @samp{-q} to prevent loading
 your init file, and @samp{-u} (or @samp{--user}) to specify a
@@ -2642,13 +2644,14 @@ Terminal Init
 @node Find Init
 @subsection How Emacs Finds Your Init File
 
-  Normally Emacs uses your home directory to find
-@file{~/.config/emacs} or @file{~/.emacs}; that's what @samp{~} means
-in a file name.  @xref{General Variables, HOME}.  If none of
-@file{~/.config/emacs}, @file{~/.emacs}, @file{~/.config/emacs.el} nor
+  Normally Emacs uses your home directory to find @file{~/.emacs}
+(@samp{~} refers to the user's home directory in a file name).
+@xref{General Variables, HOME}.  If neither @file{~/.emacs} nor
 @file{~/.emacs.el} is found, Emacs looks for
-@file{~/.config/emacs.d/init.el} or @file{~/.emacs.d/init.el} (these,
-like @file{~/.emacs.el}, can be byte-compiled).
+@file{$XDG_CONFIG_HOME/emacs/init.el}, substituting @file{~/.config}
+for @env{XDG_CONFIG_HOME} if it's not set.  If neither of these exist,
+Emacs will look for @file{~/.emacs.d/init.el}.  These, like
+@file{~/.emacs.el}, can be byte-compiled.
 
   However, if you run Emacs from a shell started by @code{su}, Emacs
 tries to find your own initialization files, not that of the user you are
@@ -2702,16 +2705,19 @@ Early Init File
 @cindex early init file
 
   Most customizations for Emacs should be put in the normal init file,
-@file{.config/emacs} or @file{~/.config/emacs.d/init.el}.  However, it is sometimes desirable
-to have customizations that take effect during Emacs startup earlier than the
-normal init file is processed.  Such customizations can be put in the early
-init file, @file{~/.config/emacs.d/early-init.el} or @file{~/.emacs.d/early-init.el}.  This file is loaded before the
-package system and GUI is initialized, so in it you can customize variables
-that affect frame appearance as well as the package initialization process,
-such as @code{package-enable-at-startup}, @code{package-load-list}, and
-@code{package-user-dir}.  Note that variables like @code{package-archives}
-which only affect the installation of new packages, and not the process of
-making already-installed packages available, may be customized in the regular
+@file{~/.emacs} or @file{$XDG_CONFIG_HOME/emacs/init.el}.  However, it
+is sometimes desirable to have customizations that take effect during
+Emacs startup earlier than the normal init file is processed.  Such
+customizations can be put in the early init file,
+@file{$XDG_CONFIG_HOME/emacs/early-init.el} or
+@file{~/.emacs.d/early-init.el}.  This file is loaded before the
+package system and GUI is initialized, so in it you can customize
+variables that affect frame appearance as well as the package
+initialization process, such as @code{package-enable-at-startup},
+@code{package-load-list}, and @code{package-user-dir}.  Note that
+variables like @code{package-archives} which only affect the
+installation of new packages, and not the process of making
+already-installed packages available, may be customized in the regular
 init file.  @xref{Package Installation}.
 
   We do not recommend that you move into @file{early-init.el}
diff --git a/etc/NEWS b/etc/NEWS
index f358a211a5..09a5e7a8aa 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -24,6 +24,12 @@ When you add a new item, use the appropriate mark if you are sure it applies,
 \f
 * Installation Changes in Emacs 27.1
 
+** Emacs now supports XDG Base Directory specification
+Emacs now uses "$XDG_CONFIG_HOME/emacs/" for 'user-emacs-directory' if
+it exists, including for the init and early init files.  If
+"$XDG_CONFIG_HOME" is not set, Emacs will use "~/.config/emacs/" if it
+exists, and will otherwise fall back to "~/.emacs.d/".
+
 ** Emacs now uses GMP, the GNU Multiple Precision library.
 By default, if 'configure' does not find a suitable libgmp, it
 arranges for the included mini-gmp library to be built and used.
diff --git a/lisp/startup.el b/lisp/startup.el
index 90046389d1..49b44fbae3 100644
--- a/lisp/startup.el
+++ b/lisp/startup.el
@@ -1,4 +1,4 @@
-;; startup.el --- process Emacs shell arguments  -*- lexical-binding: t -*-
+;;; startup.el --- process Emacs shell arguments  -*- lexical-binding: t -*-
 
 ;; Copyright (C) 1985-1986, 1992, 1994-2019 Free Software Foundation,
 ;; Inc.
@@ -971,15 +971,6 @@ startup--load-user-init-file
     (when debug-on-error-should-be-set
       (setq debug-on-error debug-on-error-from-init-file))))
 
-(defun find-init-path (fn)
-  "Look in ~/.config/FOO or ~/.FOO for the dotfile or dot directory FOO.
-It is expected that the output will undergo ~ expansion.  Implements the
-XDG convention for dotfiles."
-  (let* ((xdg-path (concat "~" init-file-user "/.config/" fn))
-        (oldstyle-path (concat "~" init-file-user "/." fn))
-        (found-path (if (file-exists-p xdg-path) xdg-path oldstyle-path)))
-    found-path))
-
 (defun command-line ()
   "A subroutine of `normal-top-level'.
 Amongst another things, it parses the command-line arguments."
@@ -1180,8 +1171,7 @@ command-line
       ;; with the .el extension, if the file doesn't exist, not just
       ;; "early-init" without an extension, as it does for ".emacs".
       "early-init.el"
-      (file-name-as-directory
-       (find-init-path "emacs.d")))))
+      (file-name-as-directory user-emacs-directory))))
   (setq early-init-file user-init-file)
 
   ;; If any package directory exists, initialize the package system.
@@ -1322,7 +1312,7 @@ command-line
         ((eq system-type 'ms-dos)
          (concat "~" init-file-user "/_emacs"))
         ((not (eq system-type 'windows-nt))
-         (find-init-path "emacs"))
+         (concat "~" init-file-user "/.emacs"))
         ;; Else deal with the Windows situation.
         ((directory-files "~" nil "^\\.emacs\\(\\.elc?\\)?$")
          ;; Prefer .emacs on Windows.
@@ -1339,8 +1329,7 @@ command-line
      (lambda ()
        (expand-file-name
         "init"
-        (file-name-as-directory
-         (find-init-path "emacs.d"))))
+        (file-name-as-directory user-emacs-directory)))
      (not inhibit-default-init))
 
     (when (and deactivate-mark transient-mark-mode)
diff --git a/lisp/subr.el b/lisp/subr.el
index 73031a2a9f..dc2a4d8373 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -2924,7 +2924,11 @@ user-emacs-directory
   (if (eq system-type 'ms-dos)
       ;; MS-DOS cannot have initial dot.
       "~/_emacs.d/"
-    "~/.emacs.d/")
+    (let ((config-dir (or (getenv "XDG_CONFIG_HOME")
+                          (concat "~" init-file-user "/.config"))))
+      (if (file-exists-p config-dir)
+          (concat config-dir "/emacs/")
+        (concat "~" init-file-user "/.emacs.d/"))))
   "Directory beneath which additional per-user Emacs-specific files are placed.
 Various programs in Emacs store information in this directory.
 Note that this should end with a directory separator.
-- 
2.21.0