code review

Signed-off-by: Jeremie Dimino <jeremie@dimino.org>

src/build_system.ml

@@ -1557,30 +1557,25 @@ let package_deps t pkg files =
         acc
       else begin
         rules_seen := Rule.Id.Set.add !rules_seen ir.id;
-        match Fiber.Once.peek ir.static_deps with
-        | None ->
-          (* We know that at this point of execution, all the relevant
-             ivars have been filled *)
-          assert false
-        | Some static_deps ->
-          let rule_deps = Static_deps.rule_deps static_deps in
-          match Rule_fn.peek (Fdecl.get t.build_rule_def) ir with
-          | None -> assert false
-          | Some (_, deps) ->
-            let dyn_deps = Deps.path_diff deps rule_deps in
-            let action_deps =
-              Static_deps.action_deps static_deps |> Deps.paths
-            in
-            Path.Set.fold (Path.Set.union action_deps dyn_deps)
-              ~init:acc ~f:loop
+        (* We know that at this point of execution, all the relevant
+           ivars have been filled so the following calsl to
+           [X.peek_exn] cannot raise. *)
+        let static_deps = Fiber.Once.peek_exn ir.static_deps in
+        let rule_deps = Static_deps.rule_deps static_deps in
+        let _, deps = Rule_fn.peek_exn (Fdecl.get t.build_rule_def) ir in
+        let dyn_deps = Deps.path_diff deps rule_deps in
+        let action_deps =
+          Static_deps.action_deps static_deps |> Deps.paths
+        in
+        Path.Set.fold (Path.Set.union action_deps dyn_deps)
+          ~init:acc ~f:loop
       end
   in
   let open Build.O in
   Build.paths_for_rule files >>^ fun () ->
   (* We know that at this point of execution, all the relevant ivars
      have been filled *)
-  Path.Set.fold files ~init:Package.Name.Set.empty
-    ~f:(fun f acc -> loop_deps f acc)
+  Path.Set.fold files ~init:Package.Name.Set.empty ~f:loop_deps
 
 (* +-----------------------------------------------------------------+
    | Adding rules to the system                                      |

src/fiber/fiber.ml

@@ -398,6 +398,8 @@ module Once = struct
     match t.state with
     | Running fut -> Future.peek fut
     | _ -> None
+
+  let peek_exn t = Option.value_exn (peek t)
 end
 
 module Mutex = struct

src/fiber/fiber.mli

@@ -135,6 +135,7 @@ module Once : sig
   (** [peek t] returns [Some v] if [get t] has already been called and
       has yielded a value [v]. *)
   val peek : 'a t -> 'a option
+  val peek_exn : 'a t -> 'a
 end with type 'a fiber := 'a t
 
 (** {1 Local storage} *)

src/memo/memo.ml

@@ -324,6 +324,8 @@ module Make(Input : Data) : S with type input := Input.t = struct
         else
           None
 
+  let peek_exn t inp = Option.value_exn (peek t inp)
+
   module Stack_frame = struct
     let input (Dep_node.T dep_node) : Input.t option =
       match dep_node.spec.witness with

src/memo/memo_intf.ml

@@ -36,6 +36,7 @@ module type S = sig
 
   (** Check whether we already have a value for the given call *)
   val peek : 'a t -> input -> 'a option
+  val peek_exn : 'a t -> input -> 'a
 
   (** After running a memoization function with a given name and
       input, it is possibly to query which dependencies that function

test/unit-tests/dag.mlt

@@ -91,16 +91,16 @@ val dag_pp_mynode : node Fmt.t = <fun>
 - : node =
 (1: k=1, i=-6) (root) [(3: k=1, i=-3) (child 1 2) [(4: k=2, i=-9) (child 2 1) [
                                                    (5: k=2, i=-8) (child 3 1) [
-                                                   ]; ]; ];
-                        (2: k=1, i=-2) (child 1 1) []; ]
+                                                   ]]];
+                        (2: k=1, i=-2) (child 1 1) []]
 val node41 : node = (6: k=1, i=-10) (child 4 1) []
 - : unit = ()
 - : node =
 (1: k=1, i=-6) (root) [(3: k=1, i=-3) (child 1 2) [(4: k=2, i=-13) (child 2 1) [
                                                    (5: k=2, i=-12) (child 3 1) [
                                                    (6: k=2, i=-11) (child 4 1) [
-                                                   ]; ]; ]; ];
-                        (2: k=1, i=-2) (child 1 1) []; ]
+                                                   ]]]];
+                        (2: k=1, i=-2) (child 1 1) []]
 - : int = 2
 - : string list option =
 Some
@@ -109,6 +109,6 @@ Some
 (1: k=3, i=-6) (root) [(3: k=3, i=-3) (child 1 2) [(4: k=3, i=-13) (child 2 1) [
                                                    (5: k=3, i=-12) (child 3 1) [
                                                    (6: k=2, i=-11) (child 4 1) [
-                                                   ]; ]; ]; ];
-                        (2: k=1, i=-2) (child 1 1) []; ]
+                                                   ]]]];
+                        (2: k=1, i=-2) (child 1 1) []]
 |}]

test/unit-tests/memoize.mlt

@@ -18,6 +18,7 @@ module String_fn :
       (string -> 'a Fiber.t) -> 'a t
     val exec : 'a t -> string -> 'a Fiber.t
     val peek : 'a t -> string -> 'a option
+    val peek_exn : 'a t -> string -> 'a
     val get_deps : 'a t -> string -> (string * Sexp.t) list option
     module Stack_frame :
       sig
@@ -35,6 +36,7 @@ module Int_fn :
       (int -> 'a Fiber.t) -> 'a t
     val exec : 'a t -> int -> 'a Fiber.t
     val peek : 'a t -> int -> 'a option
+    val peek_exn : 'a t -> int -> 'a
     val get_deps : 'a t -> int -> (string * Sexp.t) list option
     module Stack_frame :
       sig