fix(vm): self referencing closures were crashing the VM

Author: SuperFola

CHANGELOG.md

@@ -12,6 +12,7 @@
     - sys:version, has the version of the ArkScript VM
 
 ### Changed
+- fix a bug related to recursive closures: once a closure was referenced in its own scope, we couldn't convert it to string or compare it against another closure/itself
 
 ### Removed
 

include/Ark/VM/Value/Value.hpp

@@ -202,6 +202,7 @@ namespace Ark
         friend ARK_API bool operator!(const Value& A) noexcept;
 
         friend class Ark::VM;
+        friend class Ark::internal::Closure;
         friend class Ark::BytecodeReader;
         friend struct std::hash<Ark::Value>;
 

lib/std

@@ -29,11 +29,15 @@ namespace Ark::internal
         std::string out = "(";
         for (std::size_t i = 0, end = m_scope->m_data.size(); i < end; ++i)
         {
+            const auto& [id, value] = m_scope->m_data[i];
             if (i != 0)
                 out += ' ';
 
-            out += '.' + vm.m_state.m_symbols[m_scope->m_data[i].first] + '=';
-            out += m_scope->m_data[i].second.toString(vm);
+            out += '.' + vm.m_state.m_symbols[id] + '=';
+            if (value.valueType() == ValueType::Closure && value.closure().scopePtr() == scopePtr())
+                out += "Ref(self)";
+            else
+                out += value.toString(vm);
         }
         return out + ")";
     }
@@ -43,6 +47,9 @@ namespace Ark::internal
         // they do not come from the same closure builder
         if (A.m_page_addr != B.m_page_addr)
             return false;
+        // pointers are identical, we are dealing with the same object
+        if (A.m_scope.get() == B.m_scope.get())
+            return true;
 
         return *A.m_scope == *B.m_scope;
     }

src/arkreactor/VM/Value/Closure.cpp

@@ -118,4 +118,16 @@
       (if (> n 1)
         ((let F (fun (m) (if m m 1))) n))
       (set n (+ n 1)) })
-    (test:eq n 10) }) })
+    (test:eq n 10) })
+
+  (test:case "recursive structure" {
+    (let make (fun ((mut x)) {
+      (let _set (fun (y) (set x y)))
+      (fun (&x &_set) ()) }))
+    (let closure (make 1))
+    (closure._set closure)
+    (test:eq closure closure.x)
+    (test:eq closure closure.x.x)
+    (test:eq closure.x closure.x.x)
+    (test:eq closure closure.x.x.x.x.x)
+    (test:eq (toString closure) (+ "(.x=Ref(self) ._set=" (toString closure._set) ")")) }) })