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Fix dangling and reassigned Variants

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This commit addresses multiple issues with `Variant`s that point to an `Object`
which is later released, when it's tried to be accessed again.

Formerly, **while running on the debugger the system would check if the instance id was
still valid** to print warnings or return special values. Some cases weren't being
warned about whatsoever.

Also, a newly allocated `Object` could happen to be allocated at the same memory
address of an old one, making cases of use hard to find and having **`Variant`s pointing
to the old one magically reassigned to the new**.

This commit makes the engine realize all these situations **under debugging**
so you can detect and fix them. Running without a debugger attached will still
behave as it always did.

Also the warning messages have been extended and made clearer.

All that said, in the name of performance there's still one possible case of undefined
behavior: in multithreaded scripts there would be a race condition between a thread freeing
an `Object` and another one trying to operate on it. The latter may not realize the
`Object` has been freed soon enough. But that's a case of bad scripting that was never
supported anyway.
This commit is contained in:
Pedro J. Estébanez 2020-04-23 12:40:06 +02:00
parent 07c4dc1b30
commit d904d05e65
8 changed files with 378 additions and 166 deletions
Download patch file Download diff file Expand all files Collapse all files

197
core/variant_op.cpp
View file

@ -32,6 +32,7 @@
#include "core/core_string_names.h"
#include "core/object.h"
#include "core/object_rc.h"
#include "core/script_language.h"
#define CASE_TYPE_ALL(PREFIX, OP) \
@ -399,7 +400,7 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_EQUAL, NIL) {
if (p_b.type == NIL) _RETURN(true);
if (p_b.type == OBJECT)
_RETURN(p_b._get_obj().obj == NULL);
_RETURN(_OBJ_PTR(p_b) == NULL);
_RETURN(false);
}
@ -416,9 +417,9 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_EQUAL, OBJECT) {
if (p_b.type == OBJECT)
_RETURN((p_a._get_obj().obj == p_b._get_obj().obj));
_RETURN(_OBJ_PTR(p_a) == _OBJ_PTR(p_b));
if (p_b.type == NIL)
_RETURN(p_a._get_obj().obj == NULL);
_RETURN(_OBJ_PTR(p_a) == NULL);
_RETURN_FAIL;
}
@ -486,7 +487,7 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_NOT_EQUAL, NIL) {
if (p_b.type == NIL) _RETURN(false);
if (p_b.type == OBJECT)
_RETURN(p_b._get_obj().obj != NULL);
_RETURN(_OBJ_PTR(p_b) != NULL);
_RETURN(true);
}
@ -504,9 +505,9 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_NOT_EQUAL, OBJECT) {
if (p_b.type == OBJECT)
_RETURN((p_a._get_obj().obj != p_b._get_obj().obj));
_RETURN((_OBJ_PTR(p_a) != _OBJ_PTR(p_b)));
if (p_b.type == NIL)
_RETURN(p_a._get_obj().obj != NULL);
_RETURN(_OBJ_PTR(p_a) != NULL);
_RETURN_FAIL;
}
@ -589,7 +590,7 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_LESS, OBJECT) {
if (p_b.type != OBJECT)
_RETURN_FAIL;
_RETURN((p_a._get_obj().obj < p_b._get_obj().obj));
_RETURN(_OBJ_PTR(p_a) < _OBJ_PTR(p_b));
}
CASE_TYPE(math, OP_LESS, ARRAY) {
@ -643,7 +644,7 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_LESS_EQUAL, OBJECT) {
if (p_b.type != OBJECT)
_RETURN_FAIL;
_RETURN((p_a._get_obj().obj <= p_b._get_obj().obj));
_RETURN(_OBJ_PTR(p_a) <= _OBJ_PTR(p_b));
}
DEFAULT_OP_NUM(math, OP_LESS_EQUAL, INT, <=, _int);
@ -693,7 +694,7 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_GREATER, OBJECT) {
if (p_b.type != OBJECT)
_RETURN_FAIL;
_RETURN((p_a._get_obj().obj > p_b._get_obj().obj));
_RETURN(_OBJ_PTR(p_a) > _OBJ_PTR(p_b));
}
CASE_TYPE(math, OP_GREATER, ARRAY) {
@ -747,7 +748,7 @@ void Variant::evaluate(const Operator &p_op, const Variant &p_a,
CASE_TYPE(math, OP_GREATER_EQUAL, OBJECT) {
if (p_b.type != OBJECT)
_RETURN_FAIL;
_RETURN((p_a._get_obj().obj >= p_b._get_obj().obj));
_RETURN(_OBJ_PTR(p_a) >= _OBJ_PTR(p_b));
}
DEFAULT_OP_NUM(math, OP_GREATER_EQUAL, INT, >=, _int);
@ -1512,15 +1513,16 @@ void Variant::set_named(const StringName &p_index, const Variant &p_value, bool
} break;
case OBJECT: {
Object *obj = _OBJ_PTR(*this);
#ifdef DEBUG_ENABLED
if (!_get_obj().obj) {
break;
} else if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null() && !ObjectDB::instance_validate(_get_obj().obj)) {
if (unlikely(!obj)) {
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted set on a deleted object.");
}
break;
}
#endif
_get_obj().obj->set(p_index, p_value, &valid);
obj->set(p_index, p_value, &valid);
} break;
default: {
@ -1677,23 +1679,19 @@ Variant Variant::get_named(const StringName &p_index, bool *r_valid) const {
} break;
case OBJECT: {
Object *obj = _OBJ_PTR(*this);
#ifdef DEBUG_ENABLED
if (!_get_obj().obj) {
if (unlikely(!obj)) {
if (r_valid)
*r_valid = false;
return "Instance base is null.";
} else {
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null() && !ObjectDB::instance_validate(_get_obj().obj)) {
if (r_valid)
*r_valid = false;
return "Attempted use of stray pointer object.";
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted get on a deleted object.");
}
return Variant();
}
#endif
return _get_obj().obj->get(p_index, r_valid);
return obj->get(p_index, r_valid);
} break;
default: {
@ -2167,29 +2165,24 @@ void Variant::set(const Variant &p_index, const Variant &p_value, bool *r_valid)
} break;
case OBJECT: {
Object *obj = _get_obj().obj;
//only if debugging!
if (obj) {
Object *obj = _OBJ_PTR(*this);
if (unlikely(!obj)) {
#ifdef DEBUG_ENABLED
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null()) {
if (!ObjectDB::instance_validate(obj)) {
WARN_PRINT("Attempted use of stray pointer object.");
valid = false;
return;
}
valid = false;
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted set on a deleted object.");
}
#endif
if (p_index.get_type() != Variant::STRING) {
obj->setvar(p_index, p_value, r_valid);
return;
}
obj->set(p_index, p_value, r_valid);
return;
}
if (p_index.get_type() != Variant::STRING) {
obj->setvar(p_index, p_value, r_valid);
return;
}
obj->set(p_index, p_value, r_valid);
return;
} break;
case DICTIONARY: {
@ -2542,23 +2535,20 @@ Variant Variant::get(const Variant &p_index, bool *r_valid) const {
case _RID: {
} break;
case OBJECT: {
Object *obj = _get_obj().obj;
if (obj) {
Object *obj = _OBJ_PTR(*this);
if (unlikely(!obj)) {
#ifdef DEBUG_ENABLED
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null()) {
//only if debugging!
if (!ObjectDB::instance_validate(obj)) {
valid = false;
return "Attempted get on stray pointer.";
}
valid = false;
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted get on a deleted object.");
}
#endif
return Variant();
}
if (p_index.get_type() != Variant::STRING) {
return obj->getvar(p_index, r_valid);
}
if (p_index.get_type() != Variant::STRING) {
return obj->getvar(p_index, r_valid);
} else {
return obj->get(p_index, r_valid);
}
@ -2606,34 +2596,26 @@ bool Variant::in(const Variant &p_index, bool *r_valid) const {
} break;
case OBJECT: {
Object *obj = _get_obj().obj;
if (obj) {
bool valid = false;
Object *obj = _OBJ_PTR(*this);
if (unlikely(!obj)) {
#ifdef DEBUG_ENABLED
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null()) {
//only if debugging!
if (!ObjectDB::instance_validate(obj)) {
if (r_valid) {
*r_valid = false;
}
return true; // Attempted get on stray pointer.
}
if (r_valid) {
*r_valid = false;
}
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted 'in' on a deleted object.");
}
#endif
if (p_index.get_type() != Variant::STRING) {
obj->getvar(p_index, &valid);
} else {
obj->get(p_index, &valid);
}
return valid;
} else {
if (r_valid)
*r_valid = false;
return false;
}
return false;
bool result;
if (p_index.get_type() != Variant::STRING) {
obj->getvar(p_index, &result);
} else {
obj->get(p_index, &result);
}
return result;
} break;
case DICTIONARY: {
@ -2880,21 +2862,17 @@ void Variant::get_property_list(List<PropertyInfo> *p_list) const {
} break;
case OBJECT: {
Object *obj = _get_obj().obj;
if (obj) {
Object *obj = _OBJ_PTR(*this);
if (unlikely(!obj)) {
#ifdef DEBUG_ENABLED
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null()) {
//only if debugging!
if (!ObjectDB::instance_validate(obj)) {
WARN_PRINT("Attempted get_property list on stray pointer.");
return;
}
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted get property list on a deleted object.");
}
#endif
obj->get_property_list(p_list);
return;
}
obj->get_property_list(p_list);
} break;
case DICTIONARY: {
@ -2961,14 +2939,13 @@ bool Variant::iter_init(Variant &r_iter, bool &valid) const {
} break;
case OBJECT: {
Object *obj = _OBJ_PTR(*this);
#ifdef DEBUG_ENABLED
if (!_get_obj().obj) {
valid = false;
return false;
}
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null() && !ObjectDB::instance_validate(_get_obj().obj)) {
if (unlikely(!obj)) {
valid = false;
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted iteration start on a deleted object.");
}
return false;
}
#endif
@ -2978,7 +2955,7 @@ bool Variant::iter_init(Variant &r_iter, bool &valid) const {
ref.push_back(r_iter);
Variant vref = ref;
const Variant *refp[] = { &vref };
Variant ret = _get_obj().obj->call(CoreStringNames::get_singleton()->_iter_init, refp, 1, ce);
Variant ret = obj->call(CoreStringNames::get_singleton()->_iter_init, refp, 1, ce);
if (ref.size() != 1 || ce.error != Variant::CallError::CALL_OK) {
valid = false;
@ -3129,14 +3106,13 @@ bool Variant::iter_next(Variant &r_iter, bool &valid) const {
} break;
case OBJECT: {
Object *obj = _OBJ_PTR(*this);
#ifdef DEBUG_ENABLED
if (!_get_obj().obj) {
valid = false;
return false;
}
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null() && !ObjectDB::instance_validate(_get_obj().obj)) {
if (unlikely(!obj)) {
valid = false;
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted iteration check next on a deleted object.");
}
return false;
}
#endif
@ -3146,7 +3122,7 @@ bool Variant::iter_next(Variant &r_iter, bool &valid) const {
ref.push_back(r_iter);
Variant vref = ref;
const Variant *refp[] = { &vref };
Variant ret = _get_obj().obj->call(CoreStringNames::get_singleton()->_iter_next, refp, 1, ce);
Variant ret = obj->call(CoreStringNames::get_singleton()->_iter_next, refp, 1, ce);
if (ref.size() != 1 || ce.error != Variant::CallError::CALL_OK) {
valid = false;
@ -3288,21 +3264,20 @@ Variant Variant::iter_get(const Variant &r_iter, bool &r_valid) const {
} break;
case OBJECT: {
Object *obj = _OBJ_PTR(*this);
#ifdef DEBUG_ENABLED
if (!_get_obj().obj) {
r_valid = false;
return Variant();
}
if (ScriptDebugger::get_singleton() && _get_obj().ref.is_null() && !ObjectDB::instance_validate(_get_obj().obj)) {
if (unlikely(!obj)) {
r_valid = false;
if (ScriptDebugger::get_singleton() && _get_obj().instance_id != 0 && !ObjectDB::get_instance(_get_obj().instance_id)) {
WARN_PRINT("Attempted iteration get next on a deleted object.");
}
return Variant();
}
#endif
Variant::CallError ce;
ce.error = Variant::CallError::CALL_OK;
const Variant *refp[] = { &r_iter };
Variant ret = _get_obj().obj->call(CoreStringNames::get_singleton()->_iter_get, refp, 1, ce);
Variant ret = obj->call(CoreStringNames::get_singleton()->_iter_get, refp, 1, ce);
if (ce.error != Variant::CallError::CALL_OK) {
r_valid = false;