diff -r 26caf96a5fa9 -r 8cb5f96db235 mercurial/commands.py
--- a/mercurial/commands.py	Mon Oct 21 11:08:23 2019 +0200
+++ b/mercurial/commands.py	Sun Oct 06 11:06:10 2019 -0400
@@ -3310,7 +3310,7 @@
             b'all-files',
             None,
             _(
-                b'include all files in the changeset while grepping (EXPERIMENTAL)'
+                b'include all files in the changeset while grepping (DEPRECATED)'
             ),
         ),
         (b'u', b'user', None, _(b'list the author (long with -v)')),
@@ -3366,14 +3366,12 @@
     """
     opts = pycompat.byteskwargs(opts)
     diff = opts.get(b'all') or opts.get(b'diff')
-    all_files = opts.get(b'all_files')
     if diff and opts.get(b'all_files'):
         raise error.Abort(_(b'--diff and --all-files are mutually exclusive'))
-    # TODO: remove "not opts.get('rev')" if --all-files -rMULTIREV gets working
-    if opts.get(b'all_files') is None and not opts.get(b'rev') and not diff:
-        # experimental config: commands.grep.all-files
-        opts[b'all_files'] = ui.configbool(b'commands', b'grep.all-files')
+    if opts.get(b'all_files') is None and not diff:
+        opts[b'all_files'] = True
     plaingrep = opts.get(b'all_files') and not opts.get(b'rev')
+    all_files = opts.get(b'all_files')
     if plaingrep:
         opts[b'rev'] = [b'wdir()']