refactor(pkg): stop using integers for ordering (ocaml#11313)

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

src/0install-solver/cache.ml

@@ -3,10 +3,14 @@ open Fiber.O
 module Make (CacheEntry : sig
     type t
 
-    val compare : t -> t -> int
+    val compare : t -> t -> Ordering.t
   end) =
 struct
-  module M = Map.Make (CacheEntry)
+  module M = Map.Make (struct
+      include CacheEntry
+
+      let compare x y = Ordering.to_int (CacheEntry.compare x y)
+    end)
 
   type 'a snapshot = 'a M.t
   type 'a t = 'a snapshot ref

src/0install-solver/cache.mli

@@ -1,7 +1,7 @@
 module Make (CacheEntry : sig
     type t
 
-    val compare : t -> t -> int
+    val compare : t -> t -> Ordering.t
   end) : sig
   (** The cache is used in [build_problem], while the clauses are still being added. *)
   type 'a t

src/0install-solver/diagnostics.ml

@@ -171,9 +171,9 @@ module Make (Results : S.SOLVER_RESULT) = struct
         let deps = Model.requires t.role impl in
         List.find_map deps ~f:(fun dep ->
           let { Model.dep_role; _ } = Model.dep_info dep in
-          if Model.Role.compare dep_role t.role <> 0
-          then None
-          else
+          match Model.Role.compare dep_role t.role with
+          | Lt | Gt -> None
+          | Eq ->
             (* It depends on itself. *)
             Model.restrictions dep
             |> List.find_map ~f:(fun r ->
@@ -381,7 +381,8 @@ module Make (Results : S.SOLVER_RESULT) = struct
          | [] -> None
          | cl :: cls ->
            (match Classes.find classes cl with
-            | Some other_role when Model.Role.compare role other_role <> 0 ->
+            | Some other_role
+              when not (Ordering.is_eq (Model.Role.compare role other_role)) ->
               Some (`ClassConflict (other_role, cl))
             | _ -> aux cls)
        in

src/0install-solver/s.ml

@@ -15,7 +15,7 @@ module type CORE_MODEL = sig
     type t
 
     val pp : t -> 'tag Pp.t
-    val compare : t -> t -> int
+    val compare : t -> t -> Ordering.t
   end
 
   (** An [impl] is something that can fill a [Role.t] (e.g. a particular version of

src/0install-solver/solver_core.ml

@@ -312,7 +312,7 @@ module Make (Model : S.SOLVER_INPUT) = struct
         let module Requirements = struct
           type t = Output.requirements
 
-          let equal x y = Int.equal 0 (Output.Role.compare x y)
+          let equal x y = Ordering.is_eq (Output.Role.compare x y)
           let hash = Poly.hash
           let to_dyn = Dyn.opaque
         end

src/dune_pkg/opam_solver.ml

@@ -336,10 +336,10 @@ module Solver = struct
 
       let compare a b =
         match a, b with
-        | Real a, Real b -> OpamPackage.Name.compare a.name b.name
-        | Virtual (a, _), Virtual (b, _) -> Ordering.to_int (Poly.compare a b)
-        | Real _, Virtual _ -> -1
-        | Virtual _, Real _ -> 1
+        | Real a, Real b -> Ordering.of_int (OpamPackage.Name.compare a.name b.name)
+        | Virtual (a, _), Virtual (b, _) -> Poly.compare a b
+        | Real _, Virtual _ -> Lt
+        | Virtual _, Real _ -> Gt
       ;;
     end