test: update readme and the mdx test

it's complicated and hard to use in practice, because it's not obvious
if a piece of code is running under another fiber or not, so
`Fiber.spawn` might fail because it has no parent.

So in practice we've been using `Fiber.spawn_top`… which has no
interest over just using `Fut.spawn`.

README.md

@@ -173,49 +173,9 @@ val expected_sum : int = 5050
 We have a `Exn_bt.t` type that comes in handy in many places. It bundles together
 an exception and the backtrace associated with the place the exception was caught.
 
-### Fibers
+### Local storage
 
-On OCaml 5, Moonpool comes with a library `moonpool.fib` (module `Moonpool_fib`)
-which provides _lightweight fibers_
-that can run on any Moonpool runner.
-These fibers are a sort of lightweight thread, dispatched on the runner's
-background thread(s).
-Fibers rely on effects to implement `Fiber.await`, suspending themselves until the `await`-ed fiber
-is done.
-
-```ocaml
-# #require "moonpool.fib";;
-...
-
-# (* convenient alias *)
-  module F = Moonpool_fib;;
-module F = Moonpool_fib
-# F.main (fun _runner ->
-    let f1 = F.spawn (fun () -> fib 10) in
-    let f2 = F.spawn (fun () -> fib 15) in
-    F.await f1 + F.await f2);;
-- : int = 1076
-```
-
-Fibers form a _tree_, where a fiber calling `Fiber.spawn` to start a sub-fiber is
-the sub-fiber's _parent_.
-When a parent fails, all its children are cancelled (forced to fail).
-This is a simple form of [Structured Concurrency](https://en.wikipedia.org/wiki/Structured_concurrency).
-
-Like a future, a fiber eventually _resolves_ into a value (or an `Exn_bt.t`) that it's possible
-to `await`. With `Fiber.res : 'a Fiber.t -> 'a Fut.t` it's possible to access that result
-as a regular future, too.
-However, this resolution is only done after all the children of the fiber have
-resolved — the lifetime of fibers forms a well-nested tree in that sense.
-
-When a fiber is suspended because it `await`s another fiber (or future), the scheduler's
-thread on which it was running becomes available again and can go on process another task.
-When the fiber resumes, it will automatically be re-scheduled on the same runner it started on.
-This means fibers on pool P1 can await fibers from pool P2 and still be resumed on P1.
-
-In addition to all that, fibers provide _fiber local storage_ (like thread-local storage, but per fiber).
-This storage is inherited in `spawn` (as a shallow copy only — it's advisable to only
-put persistent data in storage to avoid confusing aliasing).
+Moonpool, via picos, provides _task local storage_ (like thread-local storage, but per task).
 The storage is convenient for carrying around context for cross-cutting concerns such
 as logging or tracing (e.g. a log tag for the current user or request ID, or a tracing
 scope).

dune

@@ -3,7 +3,7 @@
   (flags :standard -strict-sequence -warn-error -a+8 -w +a-4-40-42-70)))
 
 (mdx
- (libraries moonpool moonpool.forkjoin moonpool.fib threads)
+ (libraries moonpool moonpool.forkjoin threads)
  (package moonpool)
  (enabled_if
   (>= %{ocaml_version} 5.0)))

examples/discuss1.ml

@@ -1,11 +1,12 @@
-(** Example from
-    https://discuss.ocaml.org/t/confused-about-moonpool-cancellation/15381 *)
+(** NOTE: this was an example from
+    https://discuss.ocaml.org/t/confused-about-moonpool-cancellation/15381 but
+    there is no cancelation anymore :) *)
 
 let ( let@ ) = ( @@ )
 
 let () =
   let@ () = Trace_tef.with_setup () in
-  let@ _ = Moonpool_fib.main in
+  let@ _ = Moonpool.main in
 
   (* let@ runner = Moonpool.Ws_pool.with_ () in *)
   let@ runner = Moonpool.Background_thread.with_ () in
@@ -13,15 +14,13 @@ let () =
   (* Pretend this is some long-running read loop *)
   for i = 1 to 10 do
     Printf.printf "MAIN LOOP %d\n%!" i;
-    Moonpool_fib.check_if_cancelled ();
-    let _ : _ Moonpool_fib.t =
-      Moonpool_fib.spawn ~on:runner ~protect:false (fun () ->
+    let _ : _ Moonpool.Fut.t =
+      Moonpool.Fut.spawn ~on:runner (fun () ->
           Printf.printf "RUN FIBER %d\n%!" i;
-          Moonpool_fib.check_if_cancelled ();
           Format.printf "FIBER %d NOT CANCELLED YET@." i;
           failwith "BOOM")
     in
-    Moonpool_fib.yield ();
+    Moonpool.Fut.yield ();
     (* Thread.delay 0.2; *)
     (* Thread.delay 0.0001; *)
     ()

examples/dune

@@ -5,7 +5,6 @@
  ;(package moonpool)
  (libraries
   moonpool
-  moonpool.fib
   trace
   trace-tef
   ;tracy-client.trace

src/core/chan.ml

@@ -21,7 +21,6 @@ let create ~max_size () : _ t =
   }
 
 let try_push (self : _ t) x : bool =
-  let res = ref false in
   if Mutex.try_lock self.mutex then (
     if self.closed then (
       Mutex.unlock self.mutex;
@@ -33,42 +32,46 @@ let try_push (self : _ t) x : bool =
       let to_awake = Queue.create () in
       Queue.push x self.q;
       Queue.transfer self.pop_waiters to_awake;
-      res := true;
       Mutex.unlock self.mutex;
       (* wake up pop triggers if needed. Be careful to do that
          outside the critical section*)
-      Queue.iter Trigger.signal to_awake
+      Queue.iter Trigger.signal to_awake;
+      true
     | n when n < self.max_size ->
       Queue.push x self.q;
-      Mutex.unlock self.mutex
-    | _ -> Mutex.unlock self.mutex
-  );
-  !res
+      Mutex.unlock self.mutex;
+      true
+    | _ ->
+      Mutex.unlock self.mutex;
+      false
+  ) else
+    false
 
 let try_pop (type elt) self : elt option =
-  let res = ref None in
   if Mutex.try_lock self.mutex then (
-    (match Queue.pop self.q with
+    match Queue.pop self.q with
     | exception Queue.Empty ->
-      if self.closed then (
-        Mutex.unlock self.mutex;
+      Mutex.unlock self.mutex;
+      if self.closed then
         raise Closed
-      )
-    | x -> res := Some x);
-    Mutex.unlock self.mutex
-  );
-  !res
+      else
+        None
+    | x ->
+      Mutex.unlock self.mutex;
+      Some x
+  ) else
+    None
 
 let close (self : _ t) : unit =
-  let q = Queue.create () in
+  let triggers_to_signal = Queue.create () in
   Mutex.lock self.mutex;
   if not self.closed then (
     self.closed <- true;
-    Queue.transfer self.pop_waiters q;
-    Queue.transfer self.push_waiters q
+    Queue.transfer self.pop_waiters triggers_to_signal;
+    Queue.transfer self.push_waiters triggers_to_signal
   );
   Mutex.unlock self.mutex;
-  Queue.iter Trigger.signal q
+  Queue.iter Trigger.signal triggers_to_signal
 
 let rec push (self : _ t) x : unit =
   Mutex.lock self.mutex;

src/core/chan.mli

@@ -1,7 +1,8 @@
 (** Channels.
 
-    The channels have bounded size. Push/pop return futures or can use effects
-    to provide an [await]-friendly version.
+    The channels have bounded size. They use effects/await to provide
+    a direct style implementation. Pushing into a full channel,
+    or popping from an empty one, will suspend the current task.
 
     The channels became bounded since @0.7 .
 *)

src/core/fut.ml

@@ -431,12 +431,13 @@ let await (self : 'a t) : 'a =
   | exception C.Running ->
     let trigger = Trigger.create () in
     (* suspend until the future is resolved *)
-    if C.try_attach self trigger then
-      Option.iter Exn_bt.raise @@ Trigger.await trigger;
+    if C.try_attach self trigger then Trigger.await_exn trigger;
 
     (* un-suspended: we should have a result! *)
     get_or_fail_exn self
 
+let yield = Picos.Fiber.yield
+
 module Infix = struct
   let[@inline] ( >|= ) x f = map ~f x
   let[@inline] ( >>= ) x f = bind ~f x

src/core/fut.mli

@@ -8,12 +8,16 @@
     (storing a [Ok x] with [x: 'a]), or fail (storing a [Error (exn, bt)] with
     an exception and the corresponding backtrace).
 
+    Using {!spawn}, it's possible to start a bunch of tasks, obtaining futures,
+    and then use {!await} to get their result in the desired order.
+
     Combinators such as {!map} and {!join_array} can be used to produce futures
     from other futures (in a monadic way). Some combinators take a [on] argument
     to specify a runner on which the intermediate computation takes place; for
     example [map ~on:pool ~f fut] maps the value in [fut] using function [f],
     applicatively; the call to [f] happens on the runner [pool] (once [fut]
-    resolves successfully with a value). *)
+    resolves successfully with a value). Be aware that these combinators do not
+    preserve local storage. *)
 
 type 'a or_error = ('a, Exn_bt.t) result
 
@@ -30,7 +34,8 @@ val make : unit -> 'a t * 'a promise
 
 val make_promise : unit -> 'a promise
 (** Same as {!make} but returns a single promise (which can be upcast to a
-    future). This is useful mostly to preserve memory.
+    future). This is useful mostly to preserve memory, you probably don't need
+    it.
 
     How to upcast to a future in the worst case:
     {[
@@ -40,8 +45,11 @@ val make_promise : unit -> 'a promise
     @since 0.7 *)
 
 val on_result : 'a t -> ('a or_error -> unit) -> unit
-(** [on_result fut f] registers [f] to be called in the future when [fut] is set
-    ; or calls [f] immediately if [fut] is already set. *)
+(** [on_result fut f] registers [f] to be called in the future when [fut] is
+    set; or calls [f] immediately if [fut] is already set.
+
+    {b NOTE:} it's ill advised to do meaningful work inside the callback [f].
+    Instead, try to spawn another task on the runner, or use {!await}. *)
 
 val on_result_ignore : _ t -> (Exn_bt.t option -> unit) -> unit
 (** [on_result_ignore fut f] registers [f] to be called in the future when [fut]
@@ -52,13 +60,14 @@ val on_result_ignore : _ t -> (Exn_bt.t option -> unit) -> unit
 exception Already_fulfilled
 
 val try_cancel : _ promise -> Exn_bt.t -> bool
-(** [try_cancel promise ebt] tries to cancel the promise, returning [true]. It
-    returns [false] if the promise is already resolved.
-    @since NEXT_RELEASE *)
+(** [try_cancel promise ebt] tries to cancel the promise using the given
+    exception, returning [true]. It returns [false] if the promise is already
+    resolved.
+    @since 0.9 *)
 
 val cancel : _ promise -> Exn_bt.t -> unit
 (** Silent version of {!try_cancel}, ignoring the result.
-    @since NEXT_RELEASE *)
+    @since 0.9 *)
 
 val fulfill : 'a promise -> 'a or_error -> unit
 (** Fullfill the promise, setting the future at the same time.
@@ -79,6 +88,7 @@ val fail_exn_bt : Exn_bt.t -> _ t
     @since 0.6 *)
 
 val of_result : 'a or_error -> 'a t
+(** Already resolved future from a result. *)
 
 val is_resolved : _ t -> bool
 (** [is_resolved fut] is [true] iff [fut] is resolved. *)
@@ -136,7 +146,7 @@ val spawn_on_current_runner : (unit -> 'a) -> 'a t
 
 val reify_error : 'a t -> 'a or_error t
 (** [reify_error fut] turns a failing future into a non-failing one that contain
-    [Error (exn, bt)]. A non-failing future returning [x] is turned into [Ok x]
+    [Error (exn, bt)]. A non-failing future returning [x] is turned into [Ok x].
     @since 0.4 *)
 
 val map : ?on:Runner.t -> f:('a -> 'b) -> 'a t -> 'b t
@@ -149,12 +159,18 @@ val bind : ?on:Runner.t -> f:('a -> 'b t) -> 'a t -> 'b t
 (** [bind ?on ~f fut] returns a new future [fut2] that resolves like the future
     [f x] if [fut] resolved with [x]; and fails with [e] if [fut] fails with [e]
     or [f x] raises [e].
+
+    This does not preserve local storage of [fut] inside [f].
+
     @param on if provided, [f] runs on the given runner *)
 
 val bind_reify_error : ?on:Runner.t -> f:('a or_error -> 'b t) -> 'a t -> 'b t
 (** [bind_reify_error ?on ~f fut] returns a new future [fut2] that resolves like
     the future [f (Ok x)] if [fut] resolved with [x]; and resolves like the
     future [f (Error (exn, bt))] if [fut] fails with [exn] and backtrace [bt].
+
+    This does not preserve local storage of [fut] inside [f].
+
     @param on if provided, [f] runs on the given runner
     @since 0.4 *)
 
@@ -182,6 +198,7 @@ val join_array : 'a t array -> 'a array t
 val join_list : 'a t list -> 'a list t
 (** Wait for all the futures in the list. Fails if any future fails. *)
 
+(** Advanced primitives for synchronization *)
 module Advanced : sig
   val barrier_on_abstract_container_of_futures :
     iter:(('a t -> unit) -> 'cont -> unit) ->
@@ -234,7 +251,9 @@ val for_list : on:Runner.t -> 'a list -> ('a -> unit) -> unit t
 
 (** {2 Await}
 
-    {b NOTE} This is only available on OCaml 5. *)
+    This suspends the current task using an OCaml 5 algebraic effect, and makes
+    preparations for the task to be resumed once the future has been resolved.
+*)
 
 val await : 'a t -> 'a
 (** [await fut] suspends the current tasks until [fut] is fulfilled, then
@@ -244,7 +263,11 @@ val await : 'a t -> 'a
     @since 0.3
 
     This must only be run from inside the runner itself. The runner must support
-    {!Suspend_}. {b NOTE}: only on OCaml 5.x *)
+    {!Suspend_}. *)
+
+val yield : unit -> unit
+(** Like {!Moonpool.yield}.
+    @since NEXT_RELEASE *)
 
 (** {2 Blocking} *)
 
@@ -252,7 +275,7 @@ val wait_block : 'a t -> 'a or_error
 (** [wait_block fut] blocks the current thread until [fut] is resolved, and
     returns its value.
 
-    {b NOTE}: A word of warning: this will monopolize the calling thread until
+    {b NOTE:} A word of warning: this will monopolize the calling thread until
     the future resolves. This can also easily cause deadlocks, if enough threads
     in a pool call [wait_block] on futures running on the same pool or a pool
     depending on it.
@@ -265,7 +288,10 @@ val wait_block : 'a t -> 'a or_error
     the deadlock. *)
 
 val wait_block_exn : 'a t -> 'a
-(** Same as {!wait_block} but re-raises the exception if the future failed. *)
+(** Same as {!wait_block} but re-raises the exception if the future failed.
+
+    {b NOTE:} do check the cautionary note in {!wait_block} concerning
+    deadlocks. *)
 
 (** {2 Infix operators}
 
@@ -297,9 +323,10 @@ module Infix_local = Infix
 
 module Private_ : sig
   val unsafe_promise_of_fut : 'a t -> 'a promise
-  (** please do not use *)
+  (** Do not use unless you know exactly what you are doing. *)
 
   val as_computation : 'a t -> 'a Picos.Computation.t
+  (** Picos compat *)
 end
 
 (**/**)

src/core/main.ml

@@ -8,15 +8,15 @@ let main' ?(block_signals = false) () (f : Runner.t -> 'a) : 'a =
   in
   let runner = Fifo_pool.Private_.runner_of_state worker_st in
   try
-    let fiber = Fiber.spawn_top ~on:runner (fun () -> f runner) in
-    Fiber.on_result fiber (fun _ -> Runner.shutdown_without_waiting runner);
+    let fiber = Fut.spawn ~on:runner (fun () -> f runner) in
+    Fut.on_result fiber (fun _ -> Runner.shutdown_without_waiting runner);
 
     (* run the main thread *)
-    Moonpool.Private.Worker_loop_.worker_loop worker_st
+    Worker_loop_.worker_loop worker_st
       ~block_signals (* do not disturb existing thread *)
       ~ops:Fifo_pool.Private_.worker_ops;
 
-    match Fiber.peek fiber with
+    match Fut.peek fiber with
     | Some (Ok x) -> x
     | Some (Error ebt) -> Exn_bt.raise ebt
     | None -> assert false

src/core/main.mli

@@ -13,16 +13,18 @@
     to {!Background_thread} in that there's a single worker to process
     tasks/fibers.
 
-    This handles effects, including the ones in {!Fiber}.
+    This handles the concurency effects used in moonpool, including [await] and
+    [yield].
 
-    @since 0.6 *)
+    This module was migrated from the late [Moonpool_fib].
 
-val main : (Moonpool.Runner.t -> 'a) -> 'a
+    @since NEXT_RELEASE *)
+
+val main : (Runner.t -> 'a) -> 'a
 (** [main f] runs [f()] in a scope that handles effects, including
     {!Fiber.await}.
 
     This scope can run background tasks as well, in a cooperative fashion. *)
 
-val main' : ?block_signals:bool -> unit -> (Moonpool.Runner.t -> 'a) -> 'a
-(** Same as {!main} but with room for optional arguments.
-    @since 0.7 *)
+val main' : ?block_signals:bool -> unit -> (Runner.t -> 'a) -> 'a
+(** Same as {!main} but with room for optional arguments. *)

src/core/moonpool.ml

@@ -23,6 +23,7 @@ module Exn_bt = Exn_bt
 module Fifo_pool = Fifo_pool
 module Fut = Fut
 module Lock = Lock
+module Main = Main
 module Immediate_runner = struct end
 module Runner = Runner
 module Task_local_storage = Task_local_storage
@@ -30,6 +31,9 @@ module Thread_local_storage = Thread_local_storage
 module Trigger = Trigger
 module Ws_pool = Ws_pool
 
+(* re-export main *)
+include Main
+
 module Private = struct
   module Ws_deque_ = Ws_deque_
   module Worker_loop_ = Worker_loop_

src/core/moonpool.mli

@@ -13,6 +13,7 @@ module Fifo_pool = Fifo_pool
 module Background_thread = Background_thread
 module Runner = Runner
 module Trigger = Trigger
+module Main = Main
 
 module Immediate_runner : sig end
 [@@deprecated "use Moonpool_fib.Main"]
@@ -80,7 +81,7 @@ val await : 'a Fut.t -> 'a
 val yield : unit -> unit
 (** Yield from the current task, must be run on a moonpool runner. Only on OCaml
     >= 5.0.
-    @since NEXT_RELEASE *)
+    @since 0.9 *)
 
 module Lock = Lock
 module Fut = Fut
@@ -205,6 +206,10 @@ module Atomic = Atomic
     This is either a shim using [ref], on pre-OCaml 5, or the standard [Atomic]
     module on OCaml 5. *)
 
+include module type of struct
+  include Main
+end
+
 (**/**)
 
 (** Private internals, with no stability guarantees *)

src/fib/dune

@@ -1,6 +0,0 @@
-(library
- (name moonpool_fib)
- (public_name moonpool.fib)
- (synopsis "Fibers and structured concurrency for Moonpool")
- (libraries moonpool picos)
- (flags :standard -open Moonpool_private -open Moonpool))

src/fib/fiber.ml

@@ -1,334 +0,0 @@
-open Moonpool.Private.Types_
-module A = Atomic
-module FM = Handle.Map
-module Int_map = Map.Make (Int)
-module PF = Picos.Fiber
-module FLS = Picos.Fiber.FLS
-
-type 'a callback = 'a Exn_bt.result -> unit
-(** Callbacks that are called when a fiber is done. *)
-
-type cancel_callback = Exn_bt.t -> unit
-
-let prom_of_fut : 'a Fut.t -> 'a Fut.promise =
-  Fut.Private_.unsafe_promise_of_fut
-
-(* TODO: replace with picos structured at some point? *)
-module Private_ = struct
-  type pfiber = PF.t
-
-  type 'a t = {
-    id: Handle.t;  (** unique identifier for this fiber *)
-    state: 'a state A.t;  (** Current state in the lifetime of the fiber *)
-    res: 'a Fut.t;
-    runner: Runner.t;
-    pfiber: pfiber;  (** Associated picos fiber *)
-  }
-
-  and 'a state =
-    | Alive of {
-        children: children;
-        on_cancel: cancel_callback Int_map.t;
-        cancel_id: int;
-      }
-    | Terminating_or_done of 'a Exn_bt.result A.t
-
-  and children = any FM.t
-  and any = Any : _ t -> any [@@unboxed]
-
-  (** Key to access the current moonpool.fiber. *)
-  let k_current_fiber : any FLS.t = FLS.create ()
-
-  exception Not_set = FLS.Not_set
-
-  let[@inline] get_cur_from_exn (pfiber : pfiber) : any =
-    FLS.get_exn pfiber k_current_fiber
-
-  let[@inline] get_cur_exn () : any =
-    get_cur_from_exn @@ get_current_fiber_exn ()
-
-  let[@inline] get_cur_opt () = try Some (get_cur_exn ()) with _ -> None
-
-  let[@inline] is_closed (self : _ t) =
-    match A.get self.state with
-    | Alive _ -> false
-    | Terminating_or_done _ -> true
-end
-
-include Private_
-
-let create_ ~pfiber ~runner ~res () : 'a t =
-  let id = Handle.generate_fresh () in
-  {
-    state =
-      A.make
-      @@ Alive { children = FM.empty; on_cancel = Int_map.empty; cancel_id = 0 };
-    id;
-    res;
-    runner;
-    pfiber;
-  }
-
-let create_done_ ~res () : _ t =
-  let id = Handle.generate_fresh () in
-  {
-    state =
-      A.make
-      @@ Alive { children = FM.empty; on_cancel = Int_map.empty; cancel_id = 0 };
-    id;
-    res;
-    runner = Runner.dummy;
-    pfiber = Moonpool.Private.Types_._dummy_fiber;
-  }
-
-let[@inline] return x = create_done_ ~res:(Fut.return x) ()
-let[@inline] fail ebt = create_done_ ~res:(Fut.fail_exn_bt ebt) ()
-let[@inline] res self = self.res
-let[@inline] peek self = Fut.peek self.res
-let[@inline] is_done self = Fut.is_done self.res
-let[@inline] is_success self = Fut.is_success self.res
-let[@inline] is_cancelled self = Fut.is_failed self.res
-let[@inline] on_result (self : _ t) f = Fut.on_result self.res f
-let[@inline] await self = Fut.await self.res
-let[@inline] wait_block self = Fut.wait_block self.res
-let[@inline] wait_block_exn self = Fut.wait_block_exn self.res
-
-(** Resolve [promise] once [children] are all done *)
-let resolve_once_children_are_done_ ~children ~promise
-    (res : 'a Exn_bt.result A.t) : unit =
-  let n_children = FM.cardinal children in
-  if n_children > 0 then (
-    (* wait for all children to be done *)
-    let n_waiting = A.make (FM.cardinal children) in
-    let on_child_finish (r : _ result) =
-      (* make sure the parent fails if any child fails *)
-      (match r with
-      | Ok _ -> ()
-      | Error ebt -> A.set res (Error ebt));
-
-      (* if we're the last to finish, resolve the parent fiber's [res] *)
-      if A.fetch_and_add n_waiting (-1) = 1 then (
-        let res = A.get res in
-        Fut.fulfill promise res
-      )
-    in
-    FM.iter (fun _ (Any f) -> Fut.on_result f.res on_child_finish) children
-  ) else
-    Fut.fulfill promise @@ A.get res
-
-let rec resolve_as_failed_ : type a. a t -> Exn_bt.t -> unit =
- fun self ebt ->
-  let promise = prom_of_fut self.res in
-  while
-    match A.get self.state with
-    | Alive { children; cancel_id = _; on_cancel } as old ->
-      let new_st = Terminating_or_done (A.make @@ Error ebt) in
-      if A.compare_and_set self.state old new_st then (
-        (* here, unlike in {!resolve_fiber}, we immediately cancel children *)
-        cancel_children_ ~children ebt;
-        Int_map.iter (fun _ cb -> cb ebt) on_cancel;
-        resolve_once_children_are_done_ ~children ~promise (A.make @@ Error ebt);
-        false
-      ) else
-        true
-    | Terminating_or_done _ -> false
-  do
-    ()
-  done
-
-(** Cancel eagerly all children *)
-and cancel_children_ ebt ~children : unit =
-  FM.iter (fun _ (Any f) -> resolve_as_failed_ f ebt) children
-
-type cancel_handle = int
-
-let add_on_cancel (self : _ t) cb : cancel_handle =
-  let h = ref 0 in
-  while
-    match A.get self.state with
-    | Alive { children; cancel_id; on_cancel } as old ->
-      let new_st =
-        Alive
-          {
-            children;
-            cancel_id = cancel_id + 1;
-            on_cancel = Int_map.add cancel_id cb on_cancel;
-          }
-      in
-      if A.compare_and_set self.state old new_st then (
-        h := cancel_id;
-        false
-      ) else
-        true
-    | Terminating_or_done r ->
-      (match A.get r with
-      | Error ebt -> cb ebt
-      | Ok _ -> ());
-      false
-  do
-    ()
-  done;
-  !h
-
-let remove_on_cancel (self : _ t) h =
-  while
-    match A.get self.state with
-    | Alive ({ on_cancel; _ } as alive) as old ->
-      let new_st =
-        Alive { alive with on_cancel = Int_map.remove h on_cancel }
-      in
-      not (A.compare_and_set self.state old new_st)
-    | Terminating_or_done _ -> false
-  do
-    ()
-  done
-
-let with_on_cancel (self : _ t) cb (k : unit -> 'a) : 'a =
-  let h = add_on_cancel self cb in
-  Fun.protect k ~finally:(fun () -> remove_on_cancel self h)
-
-(** Successfully resolve the fiber. This might still fail if some children
-    failed. *)
-let resolve_ok_ (self : 'a t) (r : 'a) : unit =
-  let r = A.make @@ Ok r in
-  let promise = prom_of_fut self.res in
-  while
-    match A.get self.state with
-    | Alive { children; _ } as old ->
-      let new_st = Terminating_or_done r in
-      if A.compare_and_set self.state old new_st then (
-        resolve_once_children_are_done_ ~children ~promise r;
-        false
-      ) else
-        true
-    | Terminating_or_done _ -> false
-  do
-    ()
-  done
-
-let remove_child_ (self : _ t) (child : _ t) =
-  while
-    match A.get self.state with
-    | Alive ({ children; _ } as alive) as old ->
-      let new_st =
-        Alive { alive with children = FM.remove child.id children }
-      in
-      not (A.compare_and_set self.state old new_st)
-    | _ -> false
-  do
-    ()
-  done
-
-(** Add a child to [self].
-    @param protected if true, the child's failure will not affect [self]. *)
-let add_child_ ~protect (self : _ t) (child : _ t) =
-  while
-    match A.get self.state with
-    | Alive ({ children; _ } as alive) as old ->
-      let new_st =
-        Alive { alive with children = FM.add child.id (Any child) children }
-      in
-
-      if A.compare_and_set self.state old new_st then (
-        (* make sure to remove [child] from [self.children] once it's done;
-           fail [self] is [child] failed and [protect=false] *)
-        Fut.on_result child.res (function
-          | Ok _ -> remove_child_ self child
-          | Error ebt ->
-            (* child failed, we must fail too *)
-            remove_child_ self child;
-            if not protect then resolve_as_failed_ self ebt);
-        false
-      ) else
-        true
-    | Terminating_or_done r ->
-      (match A.get r with
-      | Error ebt ->
-        (* cancel child immediately *)
-        resolve_as_failed_ child ebt
-      | Ok _ -> ());
-      false
-  do
-    ()
-  done
-
-let spawn_ ~parent ~runner (f : unit -> 'a) : 'a t =
-  let res, _ = Fut.make () in
-  let pfiber = PF.create ~forbid:false (Fut.Private_.as_computation res) in
-
-  (* copy local hmap from parent, if present *)
-  Option.iter
-    (fun (p : _ t) -> Fls.Private_hmap_ls_.copy_fls p.pfiber pfiber)
-    parent;
-
-  (match parent with
-  | Some p when is_closed p -> failwith "spawn: nursery is closed"
-  | _ -> ());
-  let fib = create_ ~pfiber ~runner ~res () in
-
-  let run () =
-    (* make sure the fiber is accessible from inside itself *)
-    FLS.set pfiber k_current_fiber (Any fib);
-    try
-      let res = f () in
-      resolve_ok_ fib res
-    with exn ->
-      let bt = Printexc.get_raw_backtrace () in
-      let ebt = Exn_bt.make exn bt in
-      resolve_as_failed_ fib ebt
-  in
-
-  Runner.run_async ~fiber:pfiber runner run;
-
-  fib
-
-let spawn_top ~on f : _ t = spawn_ ~runner:on ~parent:None f
-
-let spawn ?on ?(protect = true) f : _ t =
-  (* spawn [f()] with a copy of our local storage *)
-  let (Any p) =
-    try get_cur_exn ()
-    with Not_set ->
-      failwith "Fiber.spawn: must be run from within another fiber."
-  in
-
-  let runner =
-    match on with
-    | Some r -> r
-    | None -> p.runner
-  in
-  let child = spawn_ ~parent:(Some p) ~runner f in
-  add_child_ ~protect p child;
-  child
-
-let[@inline] spawn_ignore ?on ?protect f : unit =
-  ignore (spawn ?on ?protect f : _ t)
-
-let[@inline] spawn_top_ignore ~on f : unit = ignore (spawn_top ~on f : _ t)
-
-let[@inline] self () : any =
-  match get_cur_exn () with
-  | exception Not_set -> failwith "Fiber.self: must be run from inside a fiber."
-  | f -> f
-
-let with_on_self_cancel cb (k : unit -> 'a) : 'a =
-  let (Any self) = self () in
-  let h = add_on_cancel self cb in
-  Fun.protect k ~finally:(fun () -> remove_on_cancel self h)
-
-let[@inline] check_if_cancelled_ (self : _ t) = PF.check self.pfiber
-
-let check_if_cancelled () =
-  match get_cur_exn () with
-  | exception Not_set ->
-    failwith "Fiber.check_if_cancelled: must be run from inside a fiber."
-  | Any self -> check_if_cancelled_ self
-
-let yield () : unit =
-  match get_cur_exn () with
-  | exception Not_set ->
-    failwith "Fiber.yield: must be run from inside a fiber."
-  | Any self ->
-    check_if_cancelled_ self;
-    PF.yield ();
-    check_if_cancelled_ self

src/fib/fiber.mli

@@ -1,150 +0,0 @@
-(** Fibers.
-
-    A fiber is a lightweight computation that runs cooperatively alongside other
-    fibers. In the context of moonpool, fibers have additional properties:
-
-    - they run in a moonpool runner
-    - they form a simple supervision tree, enabling a limited form of structured
-      concurrency *)
-
-type cancel_callback = Exn_bt.t -> unit
-(** A callback used in case of cancellation *)
-
-(**/**)
-
-(** Do not rely on this, it is internal implementation details. *)
-module Private_ : sig
-  type 'a state
-  type pfiber
-
-  type 'a t = private {
-    id: Handle.t;  (** unique identifier for this fiber *)
-    state: 'a state Atomic.t;  (** Current state in the lifetime of the fiber *)
-    res: 'a Fut.t;
-    runner: Runner.t;
-    pfiber: pfiber;
-  }
-  (** Type definition, exposed so that {!any} can be unboxed. Please do not rely
-      on that. *)
-
-  type any = Any : _ t -> any [@@unboxed]
-
-  exception Not_set
-
-  val get_cur_exn : unit -> any
-  (** [get_cur_exn ()] either returns the current fiber, or
-      @raise Not_set if run outside a fiber. *)
-
-  val get_cur_opt : unit -> any option
-end
-
-(**/**)
-
-type 'a t = 'a Private_.t
-(** A fiber returning a value of type ['a]. *)
-
-val res : 'a t -> 'a Fut.t
-(** Future result of the fiber. *)
-
-type 'a callback = 'a Exn_bt.result -> unit
-(** Callbacks that are called when a fiber is done. *)
-
-(** Type erased fiber *)
-type any = Private_.any = Any : _ t -> any [@@unboxed]
-
-val return : 'a -> 'a t
-val fail : Exn_bt.t -> _ t
-
-val self : unit -> any
-(** [self ()] is the current fiber. Must be run from inside a fiber.
-    @raise Failure if not run from inside a fiber. *)
-
-val peek : 'a t -> 'a Fut.or_error option
-(** Peek inside the future result *)
-
-val is_done : _ t -> bool
-(** Has the fiber completed? *)
-
-val is_cancelled : _ t -> bool
-(** Has the fiber completed with a failure? *)
-
-val is_success : _ t -> bool
-(** Has the fiber completed with a value? *)
-
-val await : 'a t -> 'a
-(** [await fib] is like [Fut.await (res fib)] *)
-
-val wait_block_exn : 'a t -> 'a
-(** [wait_block_exn fib] is [Fut.wait_block_exn (res fib)]. {b NOTE}: See
-    {!Fut.wait_block} for warnings about deadlocks. *)
-
-val wait_block : 'a t -> 'a Fut.or_error
-(** [wait_block fib] is [Fut.wait_block (res fib)]. {b NOTE}: See
-    {!Fut.wait_block} for warnings about deadlocks. *)
-
-val check_if_cancelled : unit -> unit
-(** Check if the current fiber is cancelled, in which case this raises. Must be
-    run from inside a fiber.
-    @raise e if the current fiber is cancelled with exception [e]
-    @raise Failure if not run from a fiber. *)
-
-val yield : unit -> unit
-(** Yield control to the scheduler from the current fiber.
-    @raise Failure if not run from inside a fiber. *)
-
-type cancel_handle
-(** An opaque handle for a single cancel callback in a fiber *)
-
-val add_on_cancel : _ t -> cancel_callback -> cancel_handle
-(** [add_on_cancel fib cb] adds [cb] to the list of cancel callbacks for [fib].
-    If [fib] is already cancelled, [cb] is called immediately. *)
-
-val remove_on_cancel : _ t -> cancel_handle -> unit
-(** [remove_on_cancel fib h] removes the cancel callback associated with handle
-    [h]. *)
-
-val with_on_cancel : _ t -> cancel_callback -> (unit -> 'a) -> 'a
-(** [with_on_cancel fib cb (fun () -> <e>)] evaluates [e] in a scope in which,
-    if the fiber [fib] is cancelled, [cb()] is called. If [e] returns without
-    the fiber being cancelled, this callback is removed. *)
-
-val with_on_self_cancel : cancel_callback -> (unit -> 'a) -> 'a
-(** [with_on_self_cancel cb f] calls [f()] in a scope where [cb] is added to the
-    cancel callbacks of the current fiber; and [f()] terminates, [cb] is removed
-    from the list. *)
-
-val on_result : 'a t -> 'a callback -> unit
-(** Wait for fiber to be done and call the callback with the result. If the
-    fiber is done already then the callback is invoked immediately with its
-    result. *)
-
-val spawn_top : on:Runner.t -> (unit -> 'a) -> 'a t
-(** [spawn_top ~on f] spawns a new (toplevel) fiber onto the given runner. This
-    fiber is not the child of any other fiber: its lifetime is only determined
-    by the lifetime of [f()]. *)
-
-val spawn : ?on:Runner.t -> ?protect:bool -> (unit -> 'a) -> 'a t
-(** [spawn ~protect f] spawns a sub-fiber [f_child] from a running fiber
-    [parent]. The sub-fiber [f_child] is attached to the current fiber and fails
-    if the current fiber [parent] fails.
-
-    @param on
-      if provided, start the fiber on the given runner. If not provided, use the
-      parent's runner.
-    @param protect
-      if true, when [f_child] fails, it does not affect [parent]. If false,
-      [f_child] failing also causes [parent] to fail (and therefore all other
-      children of [parent]). Default is [true].
-
-    Must be run from inside a fiber.
-    @raise Failure if not run from inside a fiber. *)
-
-val spawn_ignore : ?on:Runner.t -> ?protect:bool -> (unit -> _) -> unit
-(** [spawn_ignore f] is [ignore (spawn f)]. The fiber will still affect
-    termination of the parent, ie. the parent will exit only after this new
-    fiber exits.
-    @param on the optional runner to use, added since 0.7 *)
-
-val spawn_top_ignore : on:Runner.t -> (unit -> _) -> unit
-(** Like {!spawn_top} but ignores the result.
-    @since 0.7 *)

src/fib/fls.ml

@@ -1 +0,0 @@
-include Task_local_storage

src/fib/fls.mli

@@ -1,17 +0,0 @@
-(** Fiber-local storage.
-
-    This storage is associated to the current fiber, just like thread-local
-    storage is associated with the current thread.
-
-    See {!Moonpool.Task_local_storage} for more general information, as this is
-    based on it.
-
-    {b NOTE}: it's important to note that, while each fiber has its own storage,
-    spawning a sub-fiber [f2] from a fiber [f1] will only do a shallow copy of
-    the storage. Values inside [f1]'s storage will be physically shared with
-    [f2]. It is thus recommended to store only persistent values in the local
-    storage. *)
-
-include module type of struct
-  include Task_local_storage
-end

src/fib/handle.ml

@@ -1,14 +0,0 @@
-module A = Atomic
-
-type t = int
-
-let counter_ = A.make 0
-let equal : t -> t -> bool = ( = )
-let compare : t -> t -> int = Stdlib.compare
-let[@inline] generate_fresh () = A.fetch_and_add counter_ 1
-
-(* TODO: better hash *)
-let[@inline] hash x = x land max_int
-
-module Set = Set.Make (Int)
-module Map = Map.Make (Int)

src/fib/handle.mli

@@ -1,17 +0,0 @@
-(** The unique name of a fiber.
-
-    Each fiber has a unique handle that can be used to refer to it in maps or
-    sets. *)
-
-type t = private int
-(** Unique, opaque identifier for a fiber. *)
-
-val equal : t -> t -> bool
-val compare : t -> t -> int
-val hash : t -> int
-
-val generate_fresh : unit -> t
-(** Generate a fresh, unique identifier *)
-
-module Set : Set.S with type elt = t
-module Map : Map.S with type key = t

src/fib/moonpool_fib.ml

@@ -1,12 +0,0 @@
-(** Fibers for moonpool.
-
-    See {!Fiber} for the most important explanations.
-
-    @since 0.6. *)
-
-module Fiber = Fiber
-module Fls = Fls
-module Handle = Handle
-module Main = Main
-include Fiber
-include Main

src/forkjoin/moonpool_forkjoin.ml

@@ -64,7 +64,7 @@ module State_ = struct
       done;
 
       (* wait for the other computation to be done *)
-      if !must_await then Trigger.await trigger |> Option.iter Exn_bt.raise
+      if !must_await then Trigger.await_exn trigger
     | Right_solved _ | Both_solved _ -> assert false
 end
 
@@ -144,7 +144,7 @@ let for_ ?chunk_size n (f : int -> int -> unit) : unit =
       i := !i + len_range
     done;
 
-    Trigger.await trigger |> Option.iter Exn_bt.raise;
+    Trigger.await_exn trigger;
     Option.iter Exn_bt.raise @@ A.get failure;
     ()
   )

src/lwt/dune

@@ -5,7 +5,6 @@
   (>= %{ocaml_version} 5.0))
  (libraries
   (re_export moonpool)
-  moonpool.fib
   picos
   (re_export lwt)
   lwt.unix))

src/lwt/moonpool_lwt.ml

@@ -289,7 +289,7 @@ let[@inline] is_setup () = Option.is_some @@ Atomic.get Scheduler_state.cur_st
 let spawn_lwt f : _ Lwt.t =
   let st = Main_state.get_st () in
   let lwt_fut, lwt_prom = Lwt.wait () in
-  Moonpool_fib.spawn_top_ignore ~on:st.as_runner (fun () ->
+  M.run_async st.as_runner (fun () ->
       try
         let x = f () in
         Lwt.wakeup lwt_prom x

test/fiber/dune

@@ -6,7 +6,6 @@
  (libraries
   t_fibers
   moonpool
-  moonpool.fib
   trace
   trace-tef
   qcheck-core

test/fiber/lib/dune

@@ -2,4 +2,4 @@
  (name t_fibers)
  (package moonpool)
  (optional)
- (libraries moonpool moonpool.fib trace qcheck-core hmap))
+ (libraries moonpool trace qcheck-core hmap))

test/fiber/lib/fib.ml

@@ -1,6 +1,7 @@
-open! Moonpool
+module Chan = Moonpool.Chan
+module Exn_bt = Moonpool.Exn_bt
 module A = Atomic
-module F = Moonpool_fib.Fiber
+module Fut = Moonpool.Fut
 
 let ( let@ ) = ( @@ )
 
@@ -49,24 +50,23 @@ let logf = Log_.logf
 let run1 ~runner () =
   Printf.printf "============\nstart\n%!";
   let clock = ref TS.init in
-  let fib =
-    F.spawn_top ~on:runner @@ fun () ->
+  let fut =
+    Fut.spawn ~on:runner @@ fun () ->
     let chan_progress = Chan.create ~max_size:4 () in
     let chans = Array.init 5 (fun _ -> Chan.create ~max_size:4 ()) in
 
     let subs =
       List.init 5 (fun i ->
-          F.spawn ~protect:false @@ fun _n ->
+          Fut.spawn ~on:runner @@ fun _n ->
           Thread.delay (float i *. 0.01);
           Chan.pop chans.(i);
           Chan.push chan_progress i;
-          F.check_if_cancelled ();
           i)
     in
 
     logf (TS.tick_get clock) "wait for subs";
 
-    F.spawn_ignore (fun () ->
+    Moonpool.run_async runner (fun () ->
         for i = 0 to 4 do
           Chan.push chans.(i) ();
           let i' = Chan.pop chan_progress in
@@ -78,19 +78,15 @@ let run1 ~runner () =
        (fun i f ->
          let clock = ref (0 :: i :: clock0) in
          logf !clock "await fiber %d" i;
-         logf (TS.tick_get clock) "cur fiber[%d] is some: %b" i
-           (Option.is_some @@ F.Private_.get_cur_opt ());
-         let res = F.await f in
-         logf (TS.tick_get clock) "cur fiber[%d] is some: %b" i
-           (Option.is_some @@ F.Private_.get_cur_opt ());
-         F.yield ();
+         let res = Fut.await f in
+         Fut.yield ();
          logf (TS.tick_get clock) "res %d = %d" i res)
        subs);
 
     logf (TS.tick_get clock) "main fiber done"
   in
 
-  Fut.await @@ F.res fib;
+  Fut.await fut;
   logf (TS.tick_get clock) "main fiber exited";
   Log_.print_and_clear ();
   ()
@@ -99,15 +95,11 @@ let run2 ~runner () =
   (* same but now, cancel one of the sub-fibers *)
   Printf.printf "============\nstart\n";
 
-  let clock = ref TS.init in
-  let fib =
-    F.spawn_top ~on:runner @@ fun () ->
-    let@ () =
-      F.with_on_self_cancel (fun ebt ->
-          logf (TS.tick_get clock) "main fiber cancelled with %s"
-          @@ Exn_bt.show ebt)
-    in
+  let to_await = ref [] in
 
+  let clock = ref TS.init in
+  let fut =
+    Fut.spawn ~on:runner @@ fun () ->
     let chans_unblock = Array.init 10 (fun _i -> Chan.create ~max_size:4 ()) in
     let chan_progress = Chan.create ~max_size:4 () in
 
@@ -116,11 +108,7 @@ let run2 ~runner () =
       let clock0 = !clock in
       List.init 10 (fun i ->
           let clock = ref (0 :: i :: clock0) in
-          F.spawn ~protect:false @@ fun _n ->
-          let@ () =
-            F.with_on_self_cancel (fun _ ->
-                logf (TS.tick_get clock) "sub-fiber %d was cancelled" i)
-          in
+          Fut.spawn ~on:runner @@ fun _n ->
           Thread.delay 0.002;
 
           (* sync for determinism *)
@@ -132,46 +120,51 @@ let run2 ~runner () =
             failwith "oh no!"
           );
 
-          F.check_if_cancelled ();
           i)
     in
 
     let post = TS.tick_get clock in
     List.iteri
       (fun i fib ->
-        F.on_result fib (function
+        Fut.on_result fib (function
           | Ok _ -> logf (i :: post) "fiber %d resolved as ok" i
           | Error _ -> logf (i :: post) "fiber %d resolved as error" i))
       subs;
 
     (* sequentialize the fibers, for determinism *)
-    F.spawn_ignore (fun () ->
-        for j = 0 to 9 do
-          Chan.push chans_unblock.(j) ();
-          let j' = Chan.pop chan_progress in
-          assert (j = j')
-        done);
+    let sender =
+      Fut.spawn ~on:runner (fun () ->
+          for j = 0 to 9 do
+            Chan.push chans_unblock.(j) ();
+            let j' = Chan.pop chan_progress in
+            assert (j = j')
+          done)
+    in
+    to_await := sender :: !to_await;
 
     logf (TS.tick_get clock) "wait for subs";
     List.iteri
       (fun i f ->
         logf (TS.tick_get clock) "await fiber %d" i;
-        let res = F.await f in
+        let res = Fut.await f in
         logf (TS.tick_get clock) "res %d = %d" i res)
       subs;
     logf (TS.tick_get clock) "yield";
-    F.yield ();
+    Fut.yield ();
     logf (TS.tick_get clock) "yielded";
     logf (TS.tick_get clock) "main fiber done"
   in
 
-  F.on_result fib (function
+  Fut.on_result fut (function
     | Ok () -> logf (TS.tick_get clock) "main fiber result: ok"
     | Error ebt ->
       logf (TS.tick_get clock) "main fiber result: error %s" (Exn_bt.show ebt));
 
-  (try Fut.await @@ F.res fib
+  (try Fut.await fut
    with Failure msg -> logf (TS.tick_get clock) "main fib failed with %S" msg);
   logf (TS.tick_get clock) "main fiber exited";
+
+  List.iter Fut.await !to_await;
+
   Log_.print_and_clear ();
   ()

test/fiber/lib/fls.ml

@@ -1,7 +1,7 @@
 open! Moonpool
 module A = Atomic
-module F = Moonpool_fib.Fiber
-module FLS = Moonpool_fib.Fls
+module F = Moonpool.Fut
+module FLS = Moonpool.Task_local_storage
 
 (* ### dummy little tracing system with local storage *)
 
@@ -122,7 +122,7 @@ let run ~pool ~pool_name () =
 
     let subs =
       List.init 2 (fun idx_sub_sub ->
-          F.spawn ~protect:true (fun () ->
+          F.spawn ~on:pool (fun () ->
               sub_sub_child ~idx ~idx_child ~idx_sub ~idx_sub_sub ()))
     in
     List.iter F.await subs
@@ -133,8 +133,7 @@ let run ~pool ~pool_name () =
 
     let subs =
       List.init 2 (fun k ->
-          F.spawn ~protect:true @@ fun () ->
-          sub_child ~idx ~idx_child ~idx_sub:k ())
+          F.spawn ~on:pool @@ fun () -> sub_child ~idx ~idx_child ~idx_sub:k ())
     in
 
     let@ () =
@@ -149,16 +148,14 @@ let run ~pool ~pool_name () =
 
     let subs =
       List.init 5 (fun j ->
-          F.spawn ~protect:true @@ fun () -> top_child ~idx ~idx_child:j ())
+          F.spawn ~on:pool @@ fun () -> top_child ~idx ~idx_child:j ())
     in
 
     List.iter F.await subs
   in
 
   Printf.printf "run test on pool = %s\n" pool_name;
-  let fibs =
-    List.init 8 (fun idx -> F.spawn_top ~on:pool (fun () -> top idx))
-  in
+  let fibs = List.init 8 (fun idx -> F.spawn ~on:pool (fun () -> top idx)) in
   List.iter F.await fibs;
 
   Printf.printf "tracing complete\n";

test/fiber/t_fib1.expected

@@ -2,33 +2,21 @@
 start
 1: wait for subs
 1.0.0: await fiber 0
-1.0.1: cur fiber[0] is some: true
-1.0.2: cur fiber[0] is some: true
-1.0.3: res 0 = 0
+1.0.1: res 0 = 0
 1.1.0: await fiber 1
-1.1.1: cur fiber[1] is some: true
-1.1.2: cur fiber[1] is some: true
-1.1.3: res 1 = 1
+1.1.1: res 1 = 1
 1.2.0: await fiber 2
-1.2.1: cur fiber[2] is some: true
-1.2.2: cur fiber[2] is some: true
-1.2.3: res 2 = 2
+1.2.1: res 2 = 2
 1.3.0: await fiber 3
-1.3.1: cur fiber[3] is some: true
-1.3.2: cur fiber[3] is some: true
-1.3.3: res 3 = 3
+1.3.1: res 3 = 3
 1.4.0: await fiber 4
-1.4.1: cur fiber[4] is some: true
-1.4.2: cur fiber[4] is some: true
-1.4.3: res 4 = 4
+1.4.1: res 4 = 4
 2: main fiber done
 3: main fiber exited
 ============
 start
 1: start fibers
 1.7.1: I'm fiber 7 and I'm about to fail…
-1.8.1: sub-fiber 8 was cancelled
-1.9.1: sub-fiber 9 was cancelled
 2.0: fiber 0 resolved as ok
 2.1: fiber 1 resolved as ok
 2.2: fiber 2 resolved as ok
@@ -37,8 +25,8 @@ start
 2.5: fiber 5 resolved as ok
 2.6: fiber 6 resolved as ok
 2.7: fiber 7 resolved as error
-2.8: fiber 8 resolved as error
-2.9: fiber 9 resolved as error
+2.8: fiber 8 resolved as ok
+2.9: fiber 9 resolved as ok
 3: wait for subs
 4: await fiber 0
 5: res 0 = 0
@@ -55,7 +43,6 @@ start
 16: await fiber 6
 17: res 6 = 6
 18: await fiber 7
-19: main fiber cancelled with Failure("oh no!")
-20: main fiber result: error Failure("oh no!")
-21: main fib failed with "oh no!"
-22: main fiber exited
+19: main fiber result: error Failure("oh no!")
+20: main fib failed with "oh no!"
+21: main fiber exited

test/fiber/t_fib1.ml

@@ -1,6 +1,6 @@
 let ( let@ ) = ( @@ )
 
 let () =
-  let@ runner = Moonpool_fib.main in
+  let@ runner = Moonpool.main in
   T_fibers.Fib.run1 ~runner ();
   T_fibers.Fib.run2 ~runner ()

test/fiber/t_fls.ml

@@ -3,7 +3,7 @@ open! Moonpool
 let ( let@ ) = ( @@ )
 
 let () =
-  let@ _ = Moonpool_fib.main in
+  let@ _ = Moonpool.main in
   (let@ pool = Ws_pool.with_ () in
    T_fibers.Fls.run ~pool ~pool_name:"ws_pool" ());
 

test/fiber/t_main.ml

@@ -1,14 +1,14 @@
 open Moonpool
-module F = Moonpool_fib
+module F = Moonpool.Fut
 
 let ( let@ ) = ( @@ )
 
 let () =
   let r =
-    F.main @@ fun runner ->
-    let f1 = F.spawn (fun () -> 1) in
-    let f2 = F.spawn_top ~on:runner (fun () -> 2) in
-    let f3 = F.spawn (fun () -> F.await f1 + 10) in
+    Moonpool.main @@ fun runner ->
+    let f1 = F.spawn ~on:runner (fun () -> 1) in
+    let f2 = F.spawn ~on:runner (fun () -> 2) in
+    let f3 = F.spawn ~on:runner (fun () -> F.await f1 + 10) in
     let r = F.await f2 + F.await f3 in
     assert (r = 13);
     r
@@ -19,10 +19,10 @@ let () =
   (* run fibers in the background, await them in the main thread *)
   let@ bg = Fifo_pool.with_ ~num_threads:4 () in
   let r =
-    F.main @@ fun runner ->
-    let f1 = F.spawn_top ~on:bg (fun () -> 1) in
-    let f2 = F.spawn_top ~on:runner (fun () -> 2) in
-    let f3 = F.spawn_top ~on:bg (fun () -> F.await f1 + 10) in
+    Moonpool.main @@ fun runner ->
+    let f1 = F.spawn ~on:bg (fun () -> 1) in
+    let f2 = F.spawn ~on:runner (fun () -> 2) in
+    let f3 = F.spawn ~on:bg (fun () -> F.await f1 + 10) in
     let r = F.await f2 + F.await f3 in
     assert (r = 13);
     r
@@ -32,8 +32,8 @@ let () =
 let () =
   try
     let _r =
-      F.main @@ fun _r ->
-      let fib = F.spawn (fun () -> failwith "oops") in
+      Moonpool.main @@ fun runner ->
+      let fib = F.spawn ~on:runner (fun () -> failwith "oops") in
       F.await fib
     in
 

test/lwt/fibers/dune

@@ -6,7 +6,6 @@
  (libraries
   t_fibers
   moonpool
-  moonpool.fib
   moonpool-lwt
   hmap
   trace

test/lwt/fibers/t_fib1.expected

@@ -2,33 +2,21 @@
 start
 1: wait for subs
 1.0.0: await fiber 0
-1.0.1: cur fiber[0] is some: true
-1.0.2: cur fiber[0] is some: true
-1.0.3: res 0 = 0
+1.0.1: res 0 = 0
 1.1.0: await fiber 1
-1.1.1: cur fiber[1] is some: true
-1.1.2: cur fiber[1] is some: true
-1.1.3: res 1 = 1
+1.1.1: res 1 = 1
 1.2.0: await fiber 2
-1.2.1: cur fiber[2] is some: true
-1.2.2: cur fiber[2] is some: true
-1.2.3: res 2 = 2
+1.2.1: res 2 = 2
 1.3.0: await fiber 3
-1.3.1: cur fiber[3] is some: true
-1.3.2: cur fiber[3] is some: true
-1.3.3: res 3 = 3
+1.3.1: res 3 = 3
 1.4.0: await fiber 4
-1.4.1: cur fiber[4] is some: true
-1.4.2: cur fiber[4] is some: true
-1.4.3: res 4 = 4
+1.4.1: res 4 = 4
 2: main fiber done
 3: main fiber exited
 ============
 start
 1: start fibers
 1.7.1: I'm fiber 7 and I'm about to fail…
-1.8.1: sub-fiber 8 was cancelled
-1.9.1: sub-fiber 9 was cancelled
 2.0: fiber 0 resolved as ok
 2.1: fiber 1 resolved as ok
 2.2: fiber 2 resolved as ok
@@ -37,8 +25,8 @@ start
 2.5: fiber 5 resolved as ok
 2.6: fiber 6 resolved as ok
 2.7: fiber 7 resolved as error
-2.8: fiber 8 resolved as error
-2.9: fiber 9 resolved as error
+2.8: fiber 8 resolved as ok
+2.9: fiber 9 resolved as ok
 3: wait for subs
 4: await fiber 0
 5: res 0 = 0
@@ -55,7 +43,6 @@ start
 16: await fiber 6
 17: res 6 = 6
 18: await fiber 7
-19: main fiber cancelled with Failure("oh no!")
-20: main fiber result: error Failure("oh no!")
-21: main fib failed with "oh no!"
-22: main fiber exited
+19: main fiber result: error Failure("oh no!")
+20: main fib failed with "oh no!"
+21: main fiber exited

test/lwt/fibers/t_main.ml

@@ -1,6 +1,6 @@
 open Moonpool
 module M_lwt = Moonpool_lwt
-module F = Moonpool_fib
+module F = Moonpool.Fut
 
 let ( let@ ) = ( @@ )
 
@@ -9,9 +9,9 @@ let () =
   let@ bg = Fifo_pool.with_ ~num_threads:4 () in
   let r =
     M_lwt.lwt_main @@ fun runner ->
-    let f1 = F.spawn_top ~on:bg (fun () -> 1) in
-    let f2 = F.spawn_top ~on:runner (fun () -> 2) in
-    let f3 = F.spawn_top ~on:runner (fun () -> F.await f1 + 10) in
+    let f1 = F.spawn ~on:bg (fun () -> 1) in
+    let f2 = F.spawn ~on:runner (fun () -> 2) in
+    let f3 = F.spawn ~on:runner (fun () -> F.await f1 + 10) in
     let r = F.await f2 + F.await f3 in
     assert (r = 13);
     r
@@ -24,7 +24,7 @@ let () =
     try
       let _r =
         M_lwt.lwt_main @@ fun runner ->
-        let fib = F.spawn_top ~on:runner (fun () -> failwith "oops") in
+        let fib = F.spawn ~on:runner (fun () -> failwith "oops") in
         F.await fib
       in