diff --git a/hgext/fix.py b/hgext/fix.py
--- a/hgext/fix.py
+++ b/hgext/fix.py
@@ -802,7 +802,11 @@
         # dangerous to let it affect all files. It would be pointless to let it
         # affect no files. There is no reasonable subset of files to use as the
         # default.
-        if pattern is None:
+        if command is None:
+            ui.warn(
+                _(b'fixer tool has no command configuration: %s\n') % (name,)
+            )
+        elif pattern is None:
             ui.warn(
                 _(b'fixer tool has no pattern configuration: %s\n') % (name,)
             )
diff --git a/tests/test-fix.t b/tests/test-fix.t
--- a/tests/test-fix.t
+++ b/tests/test-fix.t
@@ -1338,6 +1338,8 @@
   fixer tool has no pattern configuration: nopattern
   $ cat foo bar
   foobar (no-eol)
+  $ hg fix --debug --working-dir --config "fix.nocommand:pattern=foo.bar"
+  fixer tool has no command configuration: nocommand
 
   $ cd ..