fix(pkg): remove dune from lock dir (#10774)

dune can't install dune anyway

Signed-off-by: Rudi Grinberg <me@rgrinberg.com>

src/dune_pkg/dune_dep.ml

@@ -0,0 +1 @@
+let name = Package_name.of_string "dune"

src/dune_pkg/dune_dep.mli

@@ -0,0 +1 @@
+val name : Package_name.t

src/dune_pkg/lock_dir.ml

@@ -334,6 +334,7 @@ let validate_packages packages =
     |> List.concat_map ~f:(fun (dependant_package : Pkg.t) ->
       List.filter_map dependant_package.depends ~f:(fun (loc, dependency) ->
         if Package_name.Map.mem packages dependency
+           || Package_name.equal dependency Dune_dep.name
         then None
         else Some { dependant_package; dependency; loc }))
   in

src/dune_pkg/opam_solver.ml

@@ -247,9 +247,10 @@ module Context_for_dune = struct
 
   let user_restrictions : t -> OpamPackage.Name.t -> OpamFormula.version_constraint option
     =
-    let dune = OpamPackage.Name.of_string "dune" in
     fun t pkg ->
-      if OpamPackage.Name.equal dune pkg then Some (`Eq, t.dune_version) else None
+    if Package_name.equal Dune_dep.name (Package_name.of_opam_package_name pkg)
+    then Some (`Eq, t.dune_version)
+    else None
   ;;
 
   let filter_deps t package filtered_formula =
@@ -786,14 +787,12 @@ let solve_lock_dir
   >>= function
   | Error _ as e -> Fiber.return e
   | Ok solution ->
-    (* don't include local packages in the lock dir *)
+    (* don't include local packages or dune in the lock dir *)
     let opam_packages_to_lock =
-      let is_local_package package =
-        OpamPackage.name package
-        |> Package_name.of_opam_package_name
-        |> Package_name.Map.mem local_packages
-      in
-      List.filter solution ~f:(Fun.negate is_local_package)
+      let is_local_package = Package_name.Map.mem local_packages in
+      List.filter solution ~f:(fun package ->
+        let name = OpamPackage.name package |> Package_name.of_opam_package_name in
+        (not (is_local_package name)) && not (Package_name.equal Dune_dep.name name))
     in
     let* candidates_cache = Fiber_cache.to_table context.candidates_cache in
     let ocaml, pkgs =

test/blackbox-tests/test-cases/pkg/implicit-dune-constraint.t

@@ -27,5 +27,4 @@ constraint.
   [1]
   $ test "4.0.0"
   Solution for dune.lock:
-  - dune.3.11.0
   - foo.0.0.1