Fix stack overflow bug.

CHANGELOG.md

@@ -13,6 +13,7 @@ Bug fixes
 * The `sync` feature now works properly in `no-std` builds (thanks [`@misssonder`](https://github.com/misssonder) [874](https://github.com/rhaiscript/rhai/pull/874)).
 * More data-race conditions are caught and returned as errors instead of panicking.
 * Missing `min` and `max` functions where both operands are floats or `Decimal` are added.
+* Fixed stack overflow when calling closures recursively (thanks [`@MageWeiG`](https://github.com/MageWeiG) [880](https://github.com/rhaiscript/rhai/issues/880)).
 
 New features
 ------------

src/func/call.rs

@@ -754,6 +754,8 @@ impl Engine {
                         let scope = &mut Scope::new();
                         let environ = fn_ptr.environ.as_ref().map(<_>::as_ref);
 
+                        defer! { let orig_level = global.level; global.level += 1 }
+
                         self.call_script_fn(
                             global, caches, scope, None, environ, fn_def, args, true, pos,
                         )
@@ -832,6 +834,8 @@ impl Engine {
                         let this_ptr = Some(target.as_mut());
                         let environ = environ.as_deref();
 
+                        defer! { let orig_level = global.level; global.level += 1 }
+
                         self.call_script_fn(
                             global, caches, scope, this_ptr, environ, &fn_def, args, true, pos,
                         )
@@ -973,6 +977,8 @@ impl Engine {
                         let this_ptr = Some(target.as_mut());
                         let args = &mut call_args.iter_mut().collect::<FnArgsVec<_>>();
 
+                        defer! { let orig_level = global.level; global.level += 1 }
+
                         self.call_script_fn(
                             global, caches, scope, this_ptr, environ, &fn_def, args, true, pos,
                         )
@@ -1083,6 +1089,8 @@ impl Engine {
                         let scope = &mut Scope::new();
                         let environ = environ.as_deref();
 
+                        defer! { let orig_level = global.level; global.level += 1 }
+
                         return self.call_script_fn(
                             global, caches, scope, None, environ, &fn_def, args, true, pos,
                         );

tests/stack.rs

@@ -1,5 +1,5 @@
 #![cfg(not(feature = "unchecked"))]
 use rhai::{Dynamic, Engine, EvalAltResult, ParseErrorType, INT};
 
 #[test]
 #[cfg(not(feature = "no_function"))]
@@ -32,6 +32,23 @@
             .unwrap_err(),
         EvalAltResult::ErrorStackOverflow(..)
     ));
+
+    #[cfg(not(feature = "no_function"))]
+    #[cfg(not(feature = "no_object"))]
+    assert!(matches!(
+        *engine
+            .run(
+                "
+                    let obj1 = #{
+                        action: || this.action(),	
+                        update: |x| this.action()
+                    };
+                    obj1.update(1)
+                "
+            )
+            .unwrap_err(),
+        EvalAltResult::ErrorStackOverflow(..)
+    ));
 }
 
 #[test]