Merge pull request #9077 from jamessan/xdg-sysinit

startup: Use $XDG_CONFIG_DIRS/nvim/sysinit.vim if it exists

runtime/doc/starting.txt

@@ -436,10 +436,11 @@ accordingly.  Vim proceeds in this order:
 	If Vim was started in Ex mode with the "-s" argument, all following
 	initializations until 4. are skipped.  Only the "-u" option is
 	interpreted.
-							*system-vimrc*
-     a. For Unix, MS-Windows, and Macintosh, the system vimrc file is read for
-	initializations.  The path of this file is shown with the
-	":version" command.  Mostly it's "$VIM/vimrc".
+						*system-vimrc* *sysinit.vim*
+     a. The system vimrc file is read for initializations.  If
+	nvim/sysinit.vim file exists in one of $XDG_CONFIG_DIRS, it will be
+	used.  Otherwise, the system vimrc file is used. The path of this file
+	is shown with the ":version" command.  Mostly it's "$VIM/sysinit.vim".
 
 						*VIMINIT* *EXINIT* *$MYVIMRC*
      b. Four places are searched for initializations.  The first that exists

src/nvim/main.c

@@ -1722,6 +1722,48 @@ static void exe_commands(mparm_T *parmp)
   TIME_MSG("executing command arguments");
 }
 
+/// Source system-wide vimrc if built with one defined
+///
+/// Does one of the following things, stops after whichever succeeds:
+///
+/// 1. Source system vimrc file from $XDG_CONFIG_DIRS/nvim/sysinit.vim
+/// 2. Source system vimrc file from $VIM
+static void do_system_initialization(void)
+{
+  char *const config_dirs = stdpaths_get_xdg_var(kXDGConfigDirs);
+  if (config_dirs != NULL) {
+    const void *iter = NULL;
+    const char path_tail[] = {
+      'n', 'v', 'i', 'm', PATHSEP,
+      's', 'y', 's', 'i', 'n', 'i', 't', '.', 'v', 'i', 'm', NUL
+    };
+    do {
+      const char *dir;
+      size_t dir_len;
+      iter = vim_env_iter(':', config_dirs, iter, &dir, &dir_len);
+      if (dir == NULL || dir_len == 0) {
+        break;
+      }
+      char *vimrc = xmalloc(dir_len + sizeof(path_tail) + 1);
+      memcpy(vimrc, dir, dir_len);
+      vimrc[dir_len] = PATHSEP;
+      memcpy(vimrc + dir_len + 1, path_tail, sizeof(path_tail));
+      if (do_source((char_u  *)vimrc, false, DOSO_NONE) != FAIL) {
+        xfree(vimrc);
+        xfree(config_dirs);
+        return;
+      }
+      xfree(vimrc);
+    } while (iter != NULL);
+    xfree(config_dirs);
+  }
+
+#ifdef SYS_VIMRC_FILE
+  // Get system wide defaults, if the file name is defined.
+  (void)do_source((char_u *)SYS_VIMRC_FILE, false, DOSO_NONE);
+#endif
+}
+
 /// Source vimrc or do other user initialization
 ///
 /// Does one of the following things, stops after whichever succeeds:
@@ -1804,10 +1846,7 @@ static void source_startup_scripts(const mparm_T *const parmp)
       }
     }
   } else if (!silent_mode) {
-#ifdef SYS_VIMRC_FILE
-    // Get system wide defaults, if the file name is defined.
-    (void) do_source((char_u *)SYS_VIMRC_FILE, false, DOSO_NONE);
-#endif
+    do_system_initialization();
 
     if (do_user_initialization()) {
       // Read initialization commands from ".vimrc" or ".exrc" in current

test/functional/core/startup_spec.lua

@@ -7,12 +7,17 @@ local eq = helpers.eq
 local eval = helpers.eval
 local feed = helpers.feed
 local funcs = helpers.funcs
+local mkdir = helpers.mkdir
 local nvim_prog = helpers.nvim_prog
 local nvim_set = helpers.nvim_set
 local read_file = helpers.read_file
 local retry = helpers.retry
+local rmdir = helpers.rmdir
+local set_session = helpers.set_session
 local sleep = helpers.sleep
+local spawn = helpers.spawn
 local iswin = helpers.iswin
+local write_file = helpers.write_file
 
 describe('startup', function()
   before_each(function()
@@ -204,3 +209,57 @@ describe('startup', function()
   end)
 end)
 
+describe('sysinit', function()
+  local xdgdir = 'Xxdg'
+  local vimdir = 'Xvim'
+  local xhome = 'Xhome'
+  local pathsep = helpers.get_pathsep()
+  local argv = {
+    nvim_prog, '--headless', '--embed', '-i', 'NONE', '-n',
+    '--cmd', 'set nomore undodir=. directory=. belloff='
+  }
+
+  before_each(function()
+    rmdir(xdgdir)
+    rmdir(vimdir)
+    rmdir(xhome)
+
+    mkdir(xdgdir)
+    mkdir(xdgdir .. pathsep .. 'nvim')
+    write_file(table.concat({xdgdir, 'nvim', 'sysinit.vim'}, pathsep), [[
+      let g:loaded = get(g:, "loaded", 0) + 1
+      let g:xdg = 1
+    ]])
+
+    mkdir(vimdir)
+    write_file(table.concat({vimdir, 'sysinit.vim'}, pathsep), [[
+      let g:loaded = get(g:, "loaded", 0) + 1
+      let g:vim = 1
+    ]])
+
+    mkdir(xhome)
+  end)
+  after_each(function()
+    rmdir(xdgdir)
+    rmdir(vimdir)
+    rmdir(xhome)
+  end)
+
+  it('prefers XDG_CONFIG_DIRS over VIM', function()
+    set_session(spawn(argv, nil,
+                      { 'HOME='..xhome,
+                        'XDG_CONFIG_DIRS='..xdgdir,
+                        'VIM='..vimdir }))
+    eq('loaded 1 xdg 1 vim 0',
+       eval('printf("loaded %d xdg %d vim %d", g:loaded, get(g:, "xdg", 0), get(g:, "vim", 0))'))
+  end)
+
+  it('uses VIM if XDG_CONFIG_DIRS unset', function()
+    set_session(spawn(argv, nil,
+                      { 'HOME='..xhome,
+                        'XDG_CONFIG_DIRS=',
+                        'VIM='..vimdir }))
+    eq('loaded 1 xdg 0 vim 1',
+       eval('printf("loaded %d xdg %d vim %d", g:loaded, get(g:, "xdg", 0), get(g:, "vim", 0))'))
+  end)
+end)