DebugHandle Weak pointer to TxContext

chain/vm/src/host/context/tx_context_ref.rs

@@ -1,4 +1,7 @@
-use std::{ops::Deref, sync::Arc};
+use std::{
+    ops::Deref,
+    sync::{Arc, Weak},
+};
 
 use crate::host::context::{TxContext, TxResult};
 
@@ -65,4 +68,9 @@ impl TxContextRef {
     pub fn into_ref(self) -> Arc<TxContext> {
         self.0
     }
+
+    /// Creates a new [`Weak`] pointer to the [`TxContext`].
+    pub fn downgrade(&self) -> Weak<TxContext> {
+        Arc::downgrade(&self.0)
+    }
 }

framework/scenario/src/api/impl_vh/debug_api.rs

@@ -1,6 +1,5 @@
 use multiversx_chain_vm::{
     executor::{VMHooks, VMHooksEarlyExit},
-    host::context::TxContextRef,
     host::vm_hooks::{TxVMHooksContext, VMHooksDispatcher},
 };
 use multiversx_sc::{chain_core::types::ReturnCode, err_msg};
@@ -32,7 +31,7 @@ impl VMHooksApiBackend for DebugApiBackend {
     where
         F: FnOnce(&mut dyn VMHooks) -> Result<R, VMHooksEarlyExit>,
     {
-        let tx_context_ref = TxContextRef(handle.context.clone());
+        let tx_context_ref = handle.to_tx_context_ref();
         let vh_context = TxVMHooksContext::new(tx_context_ref, ContractDebugInstanceState);
         let mut dispatcher = VMHooksDispatcher::new(vh_context);
         f(&mut dispatcher).unwrap_or_else(|err| ContractDebugInstanceState::early_exit_panic(err))

framework/scenario/src/api/impl_vh/debug_handle_vh.rs

@@ -1,6 +1,6 @@
-use std::sync::Arc;
+use std::sync::Weak;
 
-use multiversx_chain_vm::host::context::TxContext;
+use multiversx_chain_vm::host::context::{TxContext, TxContextRef};
 use multiversx_sc::{
     api::{HandleConstraints, RawHandle},
     codec::TryStaticCast,
@@ -10,22 +10,22 @@ use crate::executor::debug::ContractDebugStack;
 
 #[derive(Clone)]
 pub struct DebugHandle {
-    /// TODO: would be nice to be an actual TxContextRef,
-    /// but that requires changing the debugger scripts
-    pub(crate) context: Arc<TxContext>,
+    /// Only keep a weak reference to the context, to avoid stray handles keeping the context from being released.
+    /// Using the pointer after the context is released will panic.
+    pub(crate) context: Weak<TxContext>,
     raw_handle: RawHandle,
 }
 
 impl DebugHandle {
     pub fn is_on_current_context(&self) -> bool {
-        Arc::ptr_eq(
+        Weak::ptr_eq(
             &self.context,
-            &ContractDebugStack::static_peek().tx_context_ref.into_ref(),
+            &ContractDebugStack::static_peek().tx_context_ref.downgrade(),
         )
     }
 
     pub fn is_on_same_context(&self, other: &DebugHandle) -> bool {
-        Arc::ptr_eq(&self.context, &other.context)
+        Weak::ptr_eq(&self.context, &other.context)
     }
 
     pub fn assert_current_context(&self) {
@@ -34,6 +34,16 @@ impl DebugHandle {
             "Managed value not used in original context"
         );
     }
+
+    pub fn to_tx_context_ref(&self) -> TxContextRef {
+        let tx_context_arc = self.context.upgrade().unwrap_or_else(|| {
+            panic!(
+                "TxContext is no longer valid for handle {}",
+                self.raw_handle
+            )
+        });
+        TxContextRef::new(tx_context_arc)
+    }
 }
 
 impl core::fmt::Debug for DebugHandle {
@@ -45,7 +55,7 @@ impl core::fmt::Debug for DebugHandle {
 impl HandleConstraints for DebugHandle {
     fn new(handle: multiversx_sc::api::RawHandle) -> Self {
         Self {
-            context: ContractDebugStack::static_peek().tx_context_ref.into_ref(),
+            context: ContractDebugStack::static_peek().tx_context_ref.downgrade(),
             raw_handle: handle,
         }
     }
@@ -73,7 +83,7 @@ impl PartialEq<RawHandle> for DebugHandle {
 
 impl PartialEq<DebugHandle> for DebugHandle {
     fn eq(&self, other: &DebugHandle) -> bool {
-        Arc::ptr_eq(&self.context, &other.context) && self.raw_handle == other.raw_handle
+        Weak::ptr_eq(&self.context, &other.context) && self.raw_handle == other.raw_handle
     }
 }