From bff51607cfdda137d7bc55d802895d7f794d5768 Mon Sep 17 00:00:00 2001
From: Pierre-Marie Pédrot
Date: Wed, 3 Dec 2014 20:34:09 +0100
Subject: Getting rid of Exninfo hacks.

Instead of modifying exceptions to wear additional information, we instead use
a dedicated type now. All exception-using functions were modified to support
this new type, in particular Future's fix_exn-s and the tactic monad.

To solve the problem of enriching exceptions at raise time and recover this
data in the try-with handler, we use a global datastructure recording the
given piece of data imperatively that we retrieve in the try-with handler.
We ensure that such instrumented try-with destroy the data so that there
may not be confusion with another exception. To further harden the correction
of this structure, we also check for pointer equality with the last raised
exception.

The global data structure is not thread-safe for now, which is incorrect as
the STM uses threads and enriched exceptions. Yet, we splitted the patch in
two parts, so that we do not introduce dependencies to the Thread library
immediatly. This will allow to revert only the second patch if ever we
switch to OCaml-coded lightweight threads.
---
 lib/future.mli | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'lib/future.mli')

diff --git a/lib/future.mli b/lib/future.mli
index bae4fa7514..d97b46382f 100644
--- a/lib/future.mli
+++ b/lib/future.mli
@@ -66,8 +66,8 @@ module UUIDSet : Set.S with type elt = UUID.t
 exception NotReady
 
 type 'a computation
-type 'a value = [ `Val of 'a | `Exn of exn ]
-type fix_exn = exn -> exn
+type 'a value = [ `Val of 'a | `Exn of Exninfo.iexn ]
+type fix_exn = Exninfo.iexn -> Exninfo.iexn
 
 (* Build a computation, no snapshot of the global state is taken.  If you need
    to grab a copy of the state start with from_here () and then chain.
@@ -98,7 +98,7 @@ val fix_exn_of : 'a computation -> fix_exn
 (* Run remotely, returns the function to assign.
    If not blocking (the default) it raises NotReady if forced before the
    delage assigns it. *)
-type 'a assignement = [ `Val of 'a | `Exn of exn | `Comp of 'a computation]
+type 'a assignement = [ `Val of 'a | `Exn of Exninfo.iexn | `Comp of 'a computation]
 val create_delegate :
   ?blocking:bool -> fix_exn -> 'a computation * ('a assignement -> unit)
 
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