From 29a1ca67b1cd4228812c3180ea15e96aed2a42af Mon Sep 17 00:00:00 2001
From: Dibassi Brahima <brahima.dibassi@lambda-coins.com>
Date: Wed, 14 May 2025 15:26:48 +0200
Subject: [PATCH] Tezlink : Add dummy simulate operation service to Tezlink

---
 .../lib_dev/tezlink/tezos_services.ml         | 53 +++++++++++++++++++
 .../Alpha- Test the -describe endpoint.out    | 16 ++++++
 2 files changed, 69 insertions(+)

diff --git a/etherlink/bin_node/lib_dev/tezlink/tezos_services.ml b/etherlink/bin_node/lib_dev/tezlink/tezos_services.ml
index cdd4d226e648..44074a22f8b8 100644
--- a/etherlink/bin_node/lib_dev/tezlink/tezos_services.ml
+++ b/etherlink/bin_node/lib_dev/tezlink/tezos_services.ml
@@ -50,6 +50,33 @@ module Mock = struct
 
   let protocol_data : Imported_protocol.Block_header_repr.protocol_data =
     {contents; signature}
+
+  let receipts =
+    Imported_protocol.Apply_results.Operation_metadata
+      {
+        contents =
+          Single_result
+            (Manager_operation_result
+               {
+                 balance_updates = [];
+                 operation_result =
+                   Applied
+                     (Transaction_result
+                        (Transaction_to_contract_result
+                           {
+                             storage = None;
+                             lazy_storage_diff = None;
+                             balance_updates = [];
+                             ticket_receipt = [];
+                             originated_contracts = [];
+                             consumed_gas = Alpha_context.Gas.Arith.zero;
+                             storage_size = Z.zero;
+                             paid_storage_size_diff = Z.zero;
+                             allocated_destination_contract = true;
+                           }));
+                 internal_operation_results = [];
+               });
+      }
 end
 
 (* Module importing, amending, and converting, protocol types. Those types
@@ -373,6 +400,20 @@ module Imported_services = struct
       Constants_services.RPC_service.t =
     import_service Tezos_shell_services.Monitor_services.S.bootstrapped
 
+  (* TODO: https://gitlab.com/tezos/tezos/-/issues/7965 *)
+  (* We need a proper implementation *)
+  let simulate_operation :
+      ( [`POST],
+        tezlink_rpc_context,
+        tezlink_rpc_context,
+        < successor_level : bool
+        ; version : Imported_protocol_plugin.RPC.version option >,
+        int32 option * Alpha_context.packed_operation * Chain_id.t * int,
+        Alpha_context.packed_protocol_data * Imported_protocol.operation_receipt
+      )
+      Constants_services.RPC_service.t =
+    import_service Imported_protocol_plugin.RPC.Scripts.S.simulate_operation
+
   let monitor_heads :
       ( [`GET],
         unit,
@@ -505,6 +546,18 @@ let register_block_services ~l2_chain_id
            let*? block = check_block block in
            Backend.block_hash chain block)
          ~convert_output:Protocol_types.ethereum_to_tezos_block_hash
+    |> register
+       (* TODO: https://gitlab.com/tezos/tezos/-/issues/7965 *)
+       (* We need a proper implementation *)
+         ~service:Imported_services.simulate_operation
+         ~impl:(fun
+             {block = _; chain = _}
+             _param
+             ( _blocks_before_activation,
+               operation,
+               _chain_id,
+               _operation_inclusion_latency )
+           -> return (operation.protocol_data, Mock.receipts))
   in
   Tezos_rpc.Directory.prefix
     block_directory_path
diff --git a/etherlink/tezt/tests/expected/evm_sequencer.ml/Alpha- Test the -describe endpoint.out b/etherlink/tezt/tests/expected/evm_sequencer.ml/Alpha- Test the -describe endpoint.out
index f72c787eb643..23b6ef1854cf 100644
--- a/etherlink/tezt/tests/expected/evm_sequencer.ml/Alpha- Test the -describe endpoint.out	
+++ b/etherlink/tezt/tests/expected/evm_sequencer.ml/Alpha- Test the -describe endpoint.out	
@@ -48,6 +48,14 @@ Available services:
             block located `offset` blocks after it in the chain. For
             instance, the next block if `offset` is 1. The offset cannot be
             negative. 
+        - POST /tezlink/chains/<chain_id>/blocks/<block_id>/helpers/scripts/simulate_operation
+            Simulate running an operation at some future moment (based on the
+            number of blocks given in the `latency` argument), and return the
+            operation application result. The result is the same as
+            run_operation except for the consumed gas, which depends on the
+            contents of the cache at that future moment. This RPC estimates
+            future gas consumption by trying to predict the state of the
+            cache using some heuristics. 
         - GET /tezlink/chains/<chain_id>/blocks/<block_id>/protocols
             Current and next protocol. 
       - GET /tezlink/chains/<chain_id>/chain_id
@@ -123,6 +131,14 @@ Available services:
           Returns the level of the interrogated block, or the one of a block
           located `offset` blocks after it in the chain. For instance, the
           next block if `offset` is 1. The offset cannot be negative. 
+      - POST /chains/<chain_id>/blocks/<block_id>/helpers/scripts/simulate_operation
+          Simulate running an operation at some future moment (based on the
+          number of blocks given in the `latency` argument), and return the
+          operation application result. The result is the same as
+          run_operation except for the consumed gas, which depends on the
+          contents of the cache at that future moment. This RPC estimates
+          future gas consumption by trying to predict the state of the cache
+          using some heuristics. 
       - GET /chains/<chain_id>/blocks/<block_id>/protocols
           Current and next protocol. 
     - GET /chains/<chain_id>/chain_id
-- 
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