return option from handler.run

src/base/as_prover0.ml

@@ -60,18 +60,18 @@ module Provider = struct
 
   open Types.Provider
 
-  let run t stack tbl (handler : Request.Handler.t) =
+  let run t tbl (handler : Request.Handler.t) =
     match t with
     | Request rc ->
         let r = run rc tbl in
-        Request.Handler.run handler stack r
+        Request.Handler.run handler r
     | Compute c ->
-        run c tbl
+        Some (run c tbl)
     | Both (rc, c) -> (
         let r = run rc tbl in
-        match Request.Handler.run handler stack r with
-        | exception _ ->
-            run c tbl
+        match Request.Handler.run handler r with
+        | None | (exception _) ->
+            Some (run c tbl)
         | x ->
             x )
 end

src/base/as_prover_intf.ml

@@ -23,10 +23,9 @@ module type Basic = sig
 
     val run :
          ('a, 'f field) t
-      -> string list
       -> ('f field Cvar.t -> 'f field)
       -> Request.Handler.t
-      -> 'a
+      -> 'a option
   end
 
   module Handle : sig

src/base/checked_runner.ml

@@ -256,8 +256,11 @@ struct
           let old = Run_state.as_prover s in
           Run_state.set_as_prover s true ;
           let value =
-            As_prover.Provider.run p (Run_state.stack s) (get_value s)
-              (Run_state.handler s)
+            As_prover.Provider.run p (get_value s) (Run_state.handler s)
+            |> Option.value_exn
+                 ~message:
+                   ( "Unhandled request: "
+                   ^ Core_kernel.String.concat ~sep:"\n" (Run_state.stack s) )
           in
           Run_state.set_as_prover s old ;
           let var =

src/base/request.ml

@@ -24,18 +24,15 @@ module Handler = struct
 
   let fail = []
 
-  let run : t -> string list -> 'a req -> 'a =
-   fun stack0 label_stack req0 ->
+  let run : t -> 'a req -> 'a option =
+   fun stack0 req0 ->
     let rec go req = function
       | [] ->
-          raise
-            (Failure
-               ( "Unhandled request: "
-               ^ Core_kernel.String.concat ~sep:"\n" label_stack ) )
+          None
       | { handle } :: hs -> (
           match handle req with
           | Provide x ->
-              x
+              Some x
           | Delegate req' ->
               go req' hs
           | Unhandled ->

src/base/request.mli

@@ -64,5 +64,5 @@ module Handler : sig
   val push : t -> single -> t
 
   (** Run the handler on a request. Throws an error on failure. *)
-  val run : t -> string list -> 'a req -> 'a
+  val run : t -> 'a req -> 'a option
 end