Assign return value on Variant operator failure

Variant operators for String formatting and "in" could result in errors, which would return from validated_evaluate without assigning r_ret.  This would cause scripts using the return value from these operators to get results from previously run code.  Updated to return the original String value in the String formatting case, and false for "in" when an error occurs.

Author: aaronp64

core/variant/variant_op.h

@@ -923,7 +923,10 @@ class OperatorEvaluatorStringFormat<S, void> {
 	static inline void validated_evaluate(const Variant *left, const Variant *right, Variant *r_ret) {
 		bool valid = true;
 		String result = do_mod(*VariantGetInternalPtr<S>::get_ptr(left), &valid);
-		ERR_FAIL_COND_MSG(!valid, result);
+		if (unlikely(!valid)) {
+			*VariantGetInternalPtr<String>::get_ptr(r_ret) = *VariantGetInternalPtr<S>::get_ptr(left);
+			ERR_FAIL_MSG(vformat("String formatting error: %s.", result));
+		}
 		*VariantGetInternalPtr<String>::get_ptr(r_ret) = result;
 	}
 	static void ptr_evaluate(const void *left, const void *right, void *r_ret) {
@@ -948,7 +951,10 @@ class OperatorEvaluatorStringFormat<S, Array> {
 	static inline void validated_evaluate(const Variant *left, const Variant *right, Variant *r_ret) {
 		bool valid = true;
 		String result = do_mod(*VariantGetInternalPtr<S>::get_ptr(left), *VariantGetInternalPtr<Array>::get_ptr(right), &valid);
-		ERR_FAIL_COND_MSG(!valid, result);
+		if (unlikely(!valid)) {
+			*VariantGetInternalPtr<String>::get_ptr(r_ret) = *VariantGetInternalPtr<S>::get_ptr(left);
+			ERR_FAIL_MSG(vformat("String formatting error: %s.", result));
+		}
 		*VariantGetInternalPtr<String>::get_ptr(r_ret) = result;
 	}
 	static void ptr_evaluate(const void *left, const void *right, void *r_ret) {
@@ -976,7 +982,10 @@ class OperatorEvaluatorStringFormat<S, Object> {
 	static inline void validated_evaluate(const Variant *left, const Variant *right, Variant *r_ret) {
 		bool valid = true;
 		String result = do_mod(*VariantGetInternalPtr<S>::get_ptr(left), right->get_validated_object(), &valid);
-		ERR_FAIL_COND_MSG(!valid, result);
+		if (unlikely(!valid)) {
+			*VariantGetInternalPtr<String>::get_ptr(r_ret) = *VariantGetInternalPtr<S>::get_ptr(left);
+			ERR_FAIL_MSG(vformat("String formatting error: %s.", result));
+		}
 		*VariantGetInternalPtr<String>::get_ptr(r_ret) = result;
 	}
 	static void ptr_evaluate(const void *left, const void *right, void *r_ret) {
@@ -1003,7 +1012,10 @@ class OperatorEvaluatorStringFormat {
 	static inline void validated_evaluate(const Variant *left, const Variant *right, Variant *r_ret) {
 		bool valid = true;
 		String result = do_mod(*VariantGetInternalPtr<S>::get_ptr(left), *VariantGetInternalPtr<T>::get_ptr(right), &valid);
-		ERR_FAIL_COND_MSG(!valid, result);
+		if (unlikely(!valid)) {
+			*VariantGetInternalPtr<String>::get_ptr(r_ret) = *VariantGetInternalPtr<S>::get_ptr(left);
+			ERR_FAIL_MSG(vformat("String formatting error: %s.", result));
+		}
 		*VariantGetInternalPtr<String>::get_ptr(r_ret) = result;
 	}
 	static void ptr_evaluate(const void *left, const void *right, void *r_ret) {
@@ -1492,7 +1504,10 @@ class OperatorEvaluatorObjectHasPropertyString {
 	}
 	static inline void validated_evaluate(const Variant *left, const Variant *right, Variant *r_ret) {
 		Object *l = right->get_validated_object();
-		ERR_FAIL_NULL(l);
+		if (unlikely(!l)) {
+			*VariantGetInternalPtr<bool>::get_ptr(r_ret) = false;
+			ERR_FAIL_MSG("Invalid base object for 'in'.");
+		}
 		const String &a = *VariantGetInternalPtr<String>::get_ptr(left);
 
 		bool valid;
@@ -1526,7 +1541,10 @@ class OperatorEvaluatorObjectHasPropertyStringName {
 	}
 	static inline void validated_evaluate(const Variant *left, const Variant *right, Variant *r_ret) {
 		Object *l = right->get_validated_object();
-		ERR_FAIL_NULL(l);
+		if (unlikely(!l)) {
+			*VariantGetInternalPtr<bool>::get_ptr(r_ret) = false;
+			ERR_FAIL_MSG("Invalid base object for 'in'.");
+		}
 		const StringName &a = *VariantGetInternalPtr<StringName>::get_ptr(left);
 
 		bool valid;