recdef: restore old semantics (pre STM)

The Stm commit switched from an home made handling of failures to
a with_state_protection.  This was wrong, since in case of success
the global state has to be left altered.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16746 85f007b7-540e-0410-9357-904b9bb8a0f7

6 files changed, 18 insertions, 3 deletions

diff --git a/lib/future.ml b/lib/future.ml
index 1e9cada51..d8f7b3a94 100644
--- a/lib/future.ml
+++ b/lib/future.ml
@@ -111,6 +111,11 @@ let purify f x =
     v
   with e -> let e = Errors.push e in !unfreeze state; raise e
 
+let transactify f x =
+  let state = !freeze () in
+  try f x
+  with e -> let e = Errors.push e in !unfreeze state; raise e
+
 let purify_future f x =
   match !x with
   | Val _ | Exn _ | Delegated | Dropped -> f x
diff --git a/lib/future.mli b/lib/future.mli
index 39be0c180..f07d325e0 100644
--- a/lib/future.mli
+++ b/lib/future.mli
@@ -59,4 +59,6 @@ val set_freeze : (unit -> Dyn.t) -> (Dyn.t -> unit) -> unit
 
 (* Once set_freeze is called we can purify a computation *)
 val purify : ('a -> 'b) -> 'a -> 'b
+(* And also let a function alter the state but backtrack if it raises exn *)
+val transactify : ('a -> 'b) -> 'a -> 'b
 
diff --git a/library/states.ml b/library/states.ml
index a06e7ce80..ea4e7d43c 100644
--- a/library/states.ml
+++ b/library/states.ml
@@ -39,4 +39,4 @@ let with_state_protection f x =
   with reraise ->
     (unfreeze st; raise reraise)
 
-
+let with_state_protection_on_exception = Future.transactify
diff --git a/library/states.mli b/library/states.mli
index 0babae6af..fae1bfc02 100644
--- a/library/states.mli
+++ b/library/states.mli
@@ -27,3 +27,10 @@ val unfreeze : state -> unit
 
 val with_state_protection : ('a -> 'b) -> 'a -> 'b
 
+(** [with_state_protection_on_exception f x] applies [f] to [x] and restores the
+  state of the whole system as it was before applying [f] only if an
+  exception is raised.  Unlike [with_state_protection] it also takes into
+  account the proof state *)
+
+val with_state_protection_on_exception : ('a -> 'b) -> 'a -> 'b
+
diff --git a/plugins/funind/invfun.ml b/plugins/funind/invfun.ml
index bac3ad45f..00a44888f 100644
--- a/plugins/funind/invfun.ml
+++ b/plugins/funind/invfun.ml
@@ -1015,7 +1015,7 @@ let do_save () = Lemmas.save_named false
 let derive_correctness make_scheme functional_induction (funs: constant list) (graphs:inductive list) =
   let funs = Array.of_list funs and graphs = Array.of_list graphs in
   let funs_constr = Array.map mkConst funs  in
-  States.with_state_protection (fun () ->
+  States.with_state_protection_on_exception (fun () ->
     let graphs_constr = Array.map mkInd graphs in
     let lemmas_types_infos =
       Util.Array.map2_i
diff --git a/plugins/funind/recdef.ml b/plugins/funind/recdef.ml
index 7fbc1b981..831fab633 100644
--- a/plugins/funind/recdef.ml
+++ b/plugins/funind/recdef.ml
@@ -1262,6 +1262,7 @@ let open_new_goal (build_proof:tactic -> tactic -> unit) using_lemmas ref_ goal_
     ref_ := Some lemma ;
     let lid = ref [] in
     let h_num = ref (-1) in
+    Proof_global.discard_all ();
     build_proof
       (  fun gls ->
 	   let hid = next_ident_away_in_goal h_id (pf_ids_of_hyps gls) in
@@ -1512,7 +1513,7 @@ let recursive_definition is_mes function_name rec_impls type_of_f r rec_arg_num
 			   spc () ++ str"is defined" )
       )
   in
-  States.with_state_protection (fun () ->
+  States.with_state_protection_on_exception (fun () ->
     com_terminate
       tcc_lemma_name
       tcc_lemma_constr