refactor(rules): remove support for patch back into source tree

It was never allowed in the public rules without a special toggle and
there was never any use for it. It was only added b/c it was available
in the JS fork. No need to keep it around.

Signed-off-by: Rudi Grinberg <[email protected]>

<!-- ps-id: e004ffe8-5e6c-41bd-9e3c-daf693ace63a -->

src/dune_rules/rule_mode_decoder.ml

@@ -64,38 +64,5 @@ let mode_decoders =
   ]
 ;;
 
-module Extended = struct
-  type t =
-    | Normal of Rule.Mode.t
-    | Patch_back_source_tree
-
-  let patch_back_from_source_tree_syntax =
-    Dune_lang.Syntax.create
-      ~experimental:true
-      ~name:"patch-back-source-tree"
-      ~desc:"experimental support for (mode patch-back-source-tree)"
-      [ (0, 1), `Since (3, 0) ]
-  ;;
-
-  let () =
-    Dune_project.Extension.register_simple
-      patch_back_from_source_tree_syntax
-      (Dune_lang.Decoder.return [])
-  ;;
-
-  let decode =
-    sum
-      (( "patch-back-source-tree"
-       , let+ () = Dune_lang.Syntax.since patch_back_from_source_tree_syntax (0, 1) in
-         Patch_back_source_tree )
-       :: List.map mode_decoders ~f:(fun (name, dec) ->
-         ( name
-         , let+ x = dec in
-           Normal x )))
-  ;;
-
-  let field = field "mode" decode ~default:(Normal Standard)
-end
-
 let decode = sum mode_decoders
 let field = field "mode" decode ~default:Rule.Mode.Standard

src/dune_rules/rule_mode_decoder.mli

@@ -5,13 +5,5 @@ module Promote : sig
   val into_decode : Rule.Promote.Into.t Dune_lang.Decoder.t
 end
 
-module Extended : sig
-  type t =
-    | Normal of Rule.Mode.t
-    | Patch_back_source_tree
-
-  val field : t Dune_lang.Decoder.fields_parser
-end
-
 val decode : Rule.Mode.t Dune_lang.Decoder.t
 val field : Rule.Mode.t Dune_lang.Decoder.fields_parser

src/dune_rules/simple_rules.ml

@@ -117,20 +117,7 @@ let user_rule sctx ?extra_bindings ~dir ~expander (rule : Rule_conf.t) =
           ~targets
           ~targets_dir:dir
       in
-      if rule.patch_back_source_tree
-      then
-        Action_builder.With_targets.map action ~f:(fun action ->
-          (* Here we expect that [action.sandbox] is [Sandbox_config.default]
-             because the parsing of [rule] stanzas forbids having both a
-             sandboxing setting in [deps] and a [patch_back_source_tree] field
-             at the same time.
-
-             If we didn't have this restriction and [action.sandbox] was
-             something that didn't permit [Some Patch_back_source_tree], Dune
-             would crash in a way that would be difficult for the user to
-             understand. *)
-          Action.Full.add_sandbox Sandbox_mode.Set.patch_back_source_tree_only action)
-      else action
+      action
     in
     (match rule_kind ~rule ~action with
      | No_alias ->

src/dune_rules/stanzas/rule_conf.ml

@@ -11,7 +11,6 @@ type t =
   ; deps : Dep_conf.t Bindings.t
   ; action : Loc.t * Dune_lang.Action.t
   ; mode : Rule.Mode.t
-  ; patch_back_source_tree : bool
   ; locks : Locks.t
   ; loc : Loc.t
   ; enabled_if : Blang.t
@@ -73,7 +72,6 @@ let short_form =
   ; deps = Bindings.empty
   ; action = loc, action
   ; mode = Standard
-  ; patch_back_source_tree = false
   ; locks = []
   ; loc
   ; enabled_if = Blang.true_
@@ -117,7 +115,7 @@ let long_form =
           to provide a nice error message for people switching from jbuilder
           to dune. *)
        assert (not fallback)
-     and+ mode = Mode.Extended.field
+     and+ mode = Mode.field
      and+ enabled_if = Enabled_if.decode ~allowed_vars:Any ~since:(Some (1, 4)) ()
      and+ package =
        field_o
@@ -136,23 +134,6 @@ let long_form =
            )
          ]
      in
-     let mode, patch_back_source_tree =
-       match mode with
-       | Normal mode -> mode, false
-       | Patch_back_source_tree ->
-         if List.exists (Bindings.to_list deps) ~f:(function
-              | Dep_conf.Sandbox_config _ -> true
-              | _ -> false)
-         then
-           User_error.raise
-             ~loc
-             [ Pp.text
-                 "Rules with (mode patch-back-source-tree) cannot have an explicit \
-                  sandbox configuration because it is implied by (mode \
-                  patch-back-source-tree)."
-             ];
-         Standard, true
-     in
      let action =
        match action_o with
        | Some action -> action
@@ -165,17 +146,7 @@ let long_form =
          in
          field_missing ~hints loc "action"
      in
-     { targets
-     ; deps
-     ; action
-     ; mode
-     ; locks
-     ; loc
-     ; enabled_if
-     ; aliases
-     ; package
-     ; patch_back_source_tree
-     })
+     { targets; deps; action; mode; locks; loc; enabled_if; aliases; package })
 ;;
 
 let decode =
@@ -243,7 +214,6 @@ let ocamllex_to_rule loc { modules; mode; enabled_if } =
                 ; S.virt_pform __POS__ (Var Deps)
                 ] ) )
     ; mode
-    ; patch_back_source_tree = false
     ; locks = []
     ; loc
     ; enabled_if
@@ -273,7 +243,6 @@ let ocamlyacc_to_rule loc { modules; mode; enabled_if } =
                 (S.virt_text __POS__ "ocamlyacc")
                 [ S.virt_pform __POS__ (Var Deps) ] ) )
     ; mode
-    ; patch_back_source_tree = false
     ; locks = []
     ; loc
     ; enabled_if

src/dune_rules/stanzas/rule_conf.mli

@@ -5,7 +5,6 @@ type t =
   ; deps : Dep_conf.t Bindings.t
   ; action : Loc.t * Dune_lang.Action.t
   ; mode : Rule.Mode.t
-  ; patch_back_source_tree : bool
   ; locks : Locks.t
   ; loc : Loc.t
   ; enabled_if : Blang.t

src/dune_rules/test_rules.ml

@@ -102,7 +102,6 @@ let rules (t : Tests.t) ~sctx ~dir ~scope ~expander ~dir_contents =
                 , Action_unexpanded.Redirect_out (Stdout, diff.file2, Normal, run_action)
                 )
             ; mode = Standard
-            ; patch_back_source_tree = false
             ; locks = t.locks
             ; loc
             ; enabled_if = t.enabled_if