Remove Stream Proofs (#2275)

* Remove Stream Proofs They are hard to maintain and nobdy use those anymore. * Update CHANGES
mirage · Oct 2, 2023 · 2e7a6a2 · 2e7a6a2
1 parent e24b729
commit 2e7a6a2
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diff --git a/CHANGES.md b/CHANGES.md
@@ -21,6 +21,10 @@
 - **irmin-http**
   - Removed `irmin-http` since it is not compatible with generic keys.
     `irmin-grapqhl` or `irmin-server` should be used instead. (#1902, @zshipko)
+- **irmin**
+  - Removed stream proofs. We now only have Merkle tree proofs. This simplifies
+    the maintenance of that part of the code, as ensuring the correct order of
+    cached IO operations was tricky for stream proofs (#2275, @samoht)
 
 ## 3.8.0 (2023-07-06)
 
@@ -30,7 +34,7 @@
   - Change behavior of `Irmin.Conf.key` to disallow duplicate key names by
     default. Add `allow_duplicate` optional argument to override. (#2252,
     @metanivek)
-    
+
 - **irmin-pack**
   - Add maximum memory as an alternative configuration option, `lru_max_memory`,
     for setting LRU capacity. (@metanivek, #2254)
@@ -51,7 +55,7 @@
 - **irmin-cli**
   - Changed `--store irf` to `--store fs` to align the CLI with what is
     published on the Irmin website (#2243, @wyn)
-    
+
 ## 3.7.2 (2023-06-16)
 
 ### Fixed

diff --git a/examples/merkle_proofs.md b/examples/merkle_proofs.md
@@ -134,8 +134,8 @@ Here is the signature of `produce_proof`:
 val produce_proof :
   Store.repo ->
   Store.Tree.kinded_key ->
-  (Store.tree -> (Store.tree * 'a) Lwt.t) ->
-  (Store.Tree.Proof.tree Store.Tree.Proof.t * 'a) Lwt.t = <fun>
+  (Store.tree -> (Store.tree * 'a) Lwt.t) -> (Store.Tree.Proof.t * 'a) Lwt.t =
+  <fun>
 ```
 
 `produce_proof repo key_before f` is `(proof = { state; hash_before; hash_after }, f_res)`. `f` is invoked once per call to `produce_proof` and `f tree_before` is `(tree_after, f_res)`.

diff --git a/src/irmin-test/store.ml b/src/irmin-test/store.ml
@@ -1454,8 +1454,7 @@ module Make (S : Generic_key) = struct
     in
     run x test
 
-  let pp_proof = Irmin.Type.pp (S.Tree.Proof.t S.Tree.Proof.tree_t)
-  let pp_stream = Irmin.Type.pp (S.Tree.Proof.t S.Tree.Proof.stream_t)
+  let pp_proof = Irmin.Type.pp S.Tree.Proof.t
 
   let test_proofs x () =
     let test repo =
@@ -1656,19 +1655,6 @@ module Make (S : Generic_key) = struct
       in
       let* () = Lwt_list.iter_s check_proof [ f0; f1 ] in
 
-      let check_stream f =
-        let* p, () = S.Tree.produce_stream repo key f in
-        [%log.debug "Verifying stream %a" pp_stream p];
-        let+ r = S.Tree.verify_stream p f in
-        match r with
-        | Ok (_, ()) -> ()
-        | Error e ->
-            Alcotest.failf "check_stream: %a"
-              (Irmin.Type.pp S.Tree.verifier_error_t)
-              e
-      in
-      let* () = Lwt_list.iter_s check_stream [ f0; f1 ] in
-
       (* check env sharing *)
       let tree () =
         S.Tree.of_concrete
@@ -1764,47 +1750,6 @@ module Make (S : Generic_key) = struct
           (fun c -> check_bad_proof (proof ~state:c ()))
           some_contents
       in
-
-      (* test negative streams *)
-      let check_bad_stream p =
-        let+ r = S.Tree.verify_stream p f0 in
-        match r with
-        | Ok _ ->
-            Alcotest.failf "verify_stream should have failed %a" pp_stream p
-        | Error _ -> ()
-      in
-
-      let* p0, () = S.Tree.produce_stream repo key f0 in
-      let proof ?(before = S.Tree.Proof.before p0)
-          ?(after = S.Tree.Proof.after p0) ?(contents = S.Tree.Proof.state p0)
-          () =
-        S.Tree.Proof.v ~before ~after contents
-      in
-      let wrong_hash = B.Contents.Hash.hash "not the right hash!" in
-      let wrong_kinded_hash = `Node wrong_hash in
-      let* () = check_bad_stream (proof ~before:wrong_kinded_hash ()) in
-      let* () = check_bad_stream (proof ~after:wrong_kinded_hash ()) in
-      let* _ = S.Tree.verify_stream (proof ()) f0 in
-      let some_contents : S.Tree.Proof.stream list =
-        let s : S.Tree.Proof.elt list -> S.Tree.Proof.stream = List.to_seq in
-        let ok = List.of_seq (S.Tree.Proof.state p0) in
-        [
-          s [];
-          s [ Node [] ];
-          s [ Inode { length = 1024; proofs = [] } ];
-          s [ Contents "yo" ];
-          s (ok @ [ Node [] ]);
-        ]
-      in
-      let* () =
-        let x = ref 1 in
-        Lwt_list.iter_s
-          (fun c ->
-            incr x;
-            check_bad_stream (proof ~contents:c ()))
-          some_contents
-      in
-
       B.Repo.close repo
     in
     run x test