Reject --disable-promotion in dune fmt and dune promotion apply

bin/common.ml

@@ -634,6 +634,7 @@ module Builder = struct
   let default_root_is_cwd t = t.default_root_is_cwd
   let set_default_root_is_cwd t x = { t with default_root_is_cwd = x }
   let disable_log_file t = { t with trace_file = None }
+  let promote t = t.promote
   let set_promote t v = { t with promote = Some v }
   let default_target t = t.default_target
 

bin/common.mli

@@ -45,6 +45,7 @@ module Builder : sig
   val default_root_is_cwd : t -> bool
   val set_default_root_is_cwd : t -> bool -> t
   val disable_log_file : t -> t
+  val promote : t -> Dune_engine.Clflags.Promote.t option
   val set_promote : t -> Dune_engine.Clflags.Promote.t -> t
   val default_target : t -> Arg.Dep.t
   val term : t Cmdliner.Term.t

bin/fmt.ml

@@ -71,6 +71,16 @@ let command =
                   them. This takes precedence over auto-promote as that flag is assumed \
                   for this command."))
     in
+    let () =
+      match Common.Builder.promote builder with
+      | Some Never ->
+        User_error.raise
+          [ Pp.text
+              "The --disable-promotion flag is not applicable to `dune fmt`. Use \
+               --preview to display formatting changes without applying them."
+          ]
+      | _ -> ()
+    in
     let builder =
       Common.Builder.set_promote builder (if preview then Never else Automatically)
     in

bin/promotion.ml

@@ -79,6 +79,15 @@ module Apply = struct
       (* CR-someday Alizter: document this option *)
       Arg.(value & pos_all Arg.path [] & info [] ~docv:"FILE" ~doc:None)
     in
+    let () =
+      match Common.Builder.promote builder with
+      | Some Dune_engine.Clflags.Promote.Never ->
+        User_error.raise
+          [ Pp.text
+              "The --disable-promotion flag is not applicable to `dune promotion apply`."
+          ]
+      | _ -> ()
+    in
     run ~builder ~exact ~files
   ;;
 

test/blackbox-tests/test-cases/promote/disable-promotion.t/run.t

@@ -16,3 +16,15 @@ now we build without the option and see that they are present:
   foo.exe exists
   $ test -f foo.install && echo "foo.install exists"
   foo.install exists
+
+dune fmt rejects --disable-promotion:
+  $ dune fmt --disable-promotion
+  Error: The --disable-promotion flag is not applicable to `dune fmt`. Use
+  --preview to display formatting changes without applying them.
+  [1]
+
+dune promotion apply rejects --disable-promotion:
+  $ dune promotion apply --disable-promotion
+  Error: The --disable-promotion flag is not applicable to `dune promotion
+  apply`.
+  [1]