Bug: formatting did not stabilize after 10 iterations

[hannesm]

Describe the bug

I've no clue how to describe it, but:

val register : 'a Cmdliner.Term.t -> (unit -> 'a)
[@@ocamlformat "disable"]
(* the return value is (unit -> 'a), let's keep the parens although they're
   superfluous. *)
[@@ocaml.deprecated "Use Mirage_runtime.register_arg instead."]

Leads to

ocamlformat: Cannot process "lib_runtime/mirage_runtime.mli".
  Please report this bug at https://github.com/ocaml-ppx/ocamlformat/issues.
  BUG: formatting did not stabilize after 10 iterations.

How to Reproduce

See above, ocamlformat configuration:

version = 0.26.2
profile = conventional
break-infix = fit-or-vertical
parse-docstrings = true

[Julow]

I fail to reproduce the bug with 0.26.2. Can you share the entire code file ?

[hannesm]

sure:

(*
 * Copyright (c) 2014 David Sheets <sheets@alum.mit.edu>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *)

open Cmdliner

(** Mirage runtime utilities.

    {e Release %%VERSION%%} *)

(** {2 Log thresholds} *)

type log_threshold = [ `All | `Src of string ] * Logs.level option
(** The type for log threshold. A log level of [None] disables logging. *)

val set_level : default:Logs.level option -> log_threshold list -> unit
(** [set_level ~default l] set the log levels needed to have all of the log
    sources appearing in [l] be used. *)

val logs : log_threshold list Term.t
(** [logs] is a command-liner term for setting the log_threshold. *)

(** {2 Command-line converters} *)
module Conv : sig
  val log_threshold : log_threshold Cmdliner.Arg.conv
  (** [log_threshold] converts log reporter threshold. *)
end

(** {2 Manpage sections} *)
val s_net : string
(** [s_net] is used for network options. *)

val s_disk : string
(** [s_disk] is used for disk options. *)

val s_log : string
(** [s_log] is used for logging and monitoring options. *)

(** {3 Blocks} *)

val disk : string Term.t
val analyze : bool Term.t

(** {3 Startup delay} *)

val delay : int Term.t
(** The initial delay, specified in seconds, before a unikernel starting up.
    Defaults to 0. Useful for tenders and environments that take some time to
    bring devices up. *)

(** {2 Registering scheduler hooks} *)

val at_exit : (unit -> unit Lwt.t) -> unit
(** [at_exit hook] registers [hook], which will be executed before the unikernel
    exits. The first hook registered will be executed last. *)

val at_enter_iter : (unit -> unit) -> unit
(** [at_enter_iter hook] registers [hook] to be executed at the beginning of
    each event loop iteration. The first hook registered will be executed last.

    If [hook] calls {!at_enter_iter} recursively, the new hook will run only on
    the next event loop iteration. *)

val at_leave_iter : (unit -> unit) -> unit
(** [at_leave_iter hook] registers [hook] to be executed at the end of each
    event loop iteration. See {!at_enter_iter} for details. *)

(** {2 Running hooks} *)

(** This is mainly for for developers implementing new targets. *)

val run_exit_hooks : unit -> unit Lwt.t
(** [run_exit_hooks ()] calls the sequence of hooks registered with {!at_exit}
    in sequence. *)

val run_enter_iter_hooks : unit -> unit
(** [run_enter_iter_hooks ()] calls the sequence of hooks registered with
    {!at_enter_iter} in sequence. *)

val run_leave_iter_hooks : unit -> unit
(** [run_leave_iter_hooks ()] call the sequence of hooks registered with
    {!at_leave_iter} in sequence. *)

(** {2 Exit Codes} *)

val argument_error : int
(** [argument_error] is the exit code used for argument parsing errors: 64. *)

val help_version : int
(** [help_version] is the exit code used when help/version is used: 63. *)

val register_arg : 'a Cmdliner.Term.t -> (unit -> 'a)
[@@ocamlformat "disable"]
(* the return value is (unit -> 'a), let's keep the parens although they're
   superfluous. *)
(** [register_arg term] registers term to be evaluated at boot time. An example
    is: [let hello = register_arg <myterm>] (at the toplevel of the unikernel),
    and in the unikernel code
    [Logs.info (fun m -> m "hello argument is: %s" (hello ()))]. *)

(** / *)

val with_argv : unit Cmdliner.Term.t list -> string -> string array -> unit
val runtime_args : unit -> unit Cmdliner.Term.t list

val register : 'a Cmdliner.Term.t -> (unit -> 'a)
[@@ocamlformat "disable"]
(* the return value is (unit -> 'a), let's keep the parens although they're
   superfluous. *)
[@@ocaml.deprecated "Use Mirage_runtime.register_arg instead."]

As a workaround, I put the comment before the [@@ocamlformat "disable"] attribute.

[Julow]

Thanks! The issue is on

val register_arg : 'a Cmdliner.Term.t -> (unit -> 'a)
[@@ocamlformat "disable"]
(* the return value is (unit -> 'a), let's keep the parens although they're
   superfluous. *)
(** [register_arg term] registers term to be evaluated at boot time. An example
    is: [let hello = register_arg <myterm>] (at the toplevel of the unikernel),
    and in the unikernel code
    [Logs.info (fun m -> m "hello argument is: %s" (hello ()))]. *)

It also happens in structures:

let x _ = ()
[@@ocamlformat "disable"]
(* the return value is (unit -> 'a), let's keep the parens although they're
   superfluous. *)
(** [register_arg term] registers term to be evaluated at boot time. An example
   is: [let hello = register_arg <myterm>] (at the toplevel of the unikernel),
   and in the unikernel code
   [Logs.info (fun m -> m "hello argument is: %s" (hello ()))]. *)