From df1ed68d9811ea7e66cef7cf7a5a6f86d06cdc6d Mon Sep 17 00:00:00 2001
From: Anna Shaleva <shaleva.ann@nspcc.ru>
Date: Fri, 17 May 2024 14:47:19 +0300
Subject: [PATCH] native: support native method/event removal

Port a part of https://github.com/neo-project/neo/issues/3210.
A part of #3440.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
---
 pkg/core/interop/context.go     | 14 ++++++++++++--
 pkg/core/native/native_nep17.go | 25 +++++++++++++++++++------
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/pkg/core/interop/context.go b/pkg/core/interop/context.go
index bf1d8be96..7404efa66 100644
--- a/pkg/core/interop/context.go
+++ b/pkg/core/interop/context.go
@@ -144,6 +144,7 @@ type Method = func(ic *Context, args []stackitem.Item) stackitem.Item
 type MethodAndPrice struct {
 	HFSpecificMethodAndPrice
 	ActiveFrom *config.Hardfork
+	ActiveTill *config.Hardfork
 }
 
 // HFSpecificMethodAndPrice is a hardfork-specific native contract method descriptor.
@@ -160,6 +161,7 @@ type HFSpecificMethodAndPrice struct {
 type Event struct {
 	HFSpecificEvent
 	ActiveFrom *config.Hardfork
+	ActiveTill *config.Hardfork
 }
 
 // HFSpecificEvent is a hardfork-specific native contract event descriptor.
@@ -289,7 +291,8 @@ func (c *ContractMD) buildHFSpecificMD(hf config.Hardfork) {
 	w := io.NewBufBinWriter()
 	for i := range c.methods {
 		m := c.methods[i]
-		if !(m.ActiveFrom == nil || (hf != config.HFDefault && (*m.ActiveFrom).Cmp(hf) >= 0)) {
+		if !(m.ActiveFrom == nil || (hf != config.HFDefault && (*m.ActiveFrom).Cmp(hf) >= 0)) ||
+			(m.ActiveTill != nil && (*m.ActiveTill).Cmp(hf) <= 0) {
 			continue
 		}
 
@@ -311,7 +314,8 @@ func (c *ContractMD) buildHFSpecificMD(hf config.Hardfork) {
 	}
 	for i := range c.events {
 		e := c.events[i]
-		if !(e.ActiveFrom == nil || (hf != config.HFDefault && (*e.ActiveFrom).Cmp(hf) >= 0)) {
+		if !(e.ActiveFrom == nil || (hf != config.HFDefault && (*e.ActiveFrom).Cmp(hf) >= 0)) ||
+			(e.ActiveTill != nil && (*e.ActiveTill).Cmp(hf) <= 0) {
 			continue
 		}
 
@@ -369,6 +373,9 @@ func (c *ContractMD) AddMethod(md *MethodAndPrice, desc *manifest.Method) {
 	if md.ActiveFrom != nil {
 		c.ActiveHFs[*md.ActiveFrom] = struct{}{}
 	}
+	if md.ActiveTill != nil {
+		c.ActiveHFs[*md.ActiveTill] = struct{}{}
+	}
 }
 
 // GetMethodByOffset returns method with the provided offset.
@@ -410,6 +417,9 @@ func (c *ContractMD) AddEvent(md Event) {
 	if md.ActiveFrom != nil {
 		c.ActiveHFs[*md.ActiveFrom] = struct{}{}
 	}
+	if md.ActiveTill != nil {
+		c.ActiveHFs[*md.ActiveTill] = struct{}{}
+	}
 }
 
 // Sort sorts interop functions by id.
diff --git a/pkg/core/native/native_nep17.go b/pkg/core/native/native_nep17.go
index 8c876abbc..c179fb568 100644
--- a/pkg/core/native/native_nep17.go
+++ b/pkg/core/native/native_nep17.go
@@ -323,7 +323,10 @@ func newDescriptor(name string, ret smartcontract.ParamType, ps ...manifest.Para
 	}
 }
 
-func newMethodAndPrice(f interop.Method, cpuFee int64, flags callflag.CallFlag, activeFrom ...config.Hardfork) *interop.MethodAndPrice {
+// newMethodAndPrice builds method with the provided descriptor and ActiveFrom/ActiveTill hardfork
+// values consequently specified via activations. [config.HFDefault] specfied as ActiveFrom is treated
+// as active starting from the genesis block.
+func newMethodAndPrice(f interop.Method, cpuFee int64, flags callflag.CallFlag, activations ...config.Hardfork) *interop.MethodAndPrice {
 	md := &interop.MethodAndPrice{
 		HFSpecificMethodAndPrice: interop.HFSpecificMethodAndPrice{
 			Func:          f,
@@ -331,8 +334,13 @@ func newMethodAndPrice(f interop.Method, cpuFee int64, flags callflag.CallFlag,
 			RequiredFlags: flags,
 		},
 	}
-	if len(activeFrom) != 0 {
-		md.ActiveFrom = &activeFrom[0]
+	if len(activations) > 0 {
+		if activations[0] != config.HFDefault {
+			md.ActiveFrom = &activations[0]
+		}
+	}
+	if len(activations) > 1 {
+		md.ActiveTill = &activations[1]
 	}
 	return md
 }
@@ -347,14 +355,19 @@ func newEventDescriptor(name string, ps ...manifest.Parameter) *manifest.Event {
 	}
 }
 
-func newEvent(desc *manifest.Event, activeFrom ...config.Hardfork) interop.Event {
+// newEvent builds event with the provided descriptor and ActiveFrom/ActiveTill hardfork
+// values consequently specified via activations.
+func newEvent(desc *manifest.Event, activations ...config.Hardfork) interop.Event {
 	md := interop.Event{
 		HFSpecificEvent: interop.HFSpecificEvent{
 			MD: desc,
 		},
 	}
-	if len(activeFrom) != 0 {
-		md.ActiveFrom = &activeFrom[0]
+	if len(activations) > 0 {
+		md.ActiveFrom = &activations[0]
+	}
+	if len(activations) > 1 {
+		md.ActiveTill = &activations[1]
 	}
 	return md
 }