[3.x] Fix crash on get_joy_button_index_from_string and get_joy_axis_index_from_string for non-existing key

[Snowapril]

This revision fixes issue #59175.

int InputDefault::get_joy_button_index_from_string(String p_button) {
	for (int i = 0; i < JOY_BUTTON_MAX; i++) {
		if (p_button == _buttons[i]) {
			return i;
		}
	}
	ERR_FAIL_V(-1);
}

int InputDefault::get_joy_axis_index_from_string(String p_axis) {
	for (int i = 0; i < JOY_AXIS_MAX; i++) {
		if (p_axis == _axes[i]) {
			return i;
		}
	}
	ERR_FAIL_V(-1);
}

As _buttons and _axes have both valid string and nullptr.
When iterating over them, if a given key exists it will work correctly.

But if given key does not exist, it will end up with String::operator=(nullptr).
As String constructor from nullptr exists, I use it.

JOY_BUTTON_MAX have value 128 and only used parts of array have max length only 23.
When iterating over them, adding check for nullptr and early-quit is also considerable.

Bugsquad edit:

• Fixes Passing nonexisting button name to Input.get_joy_button_index_from_string crashes Godot 3.4.3 #59175

[akien-mga]

When iterating over them, adding check for nullptr and early-quit is also considerable.

I would add this too to be safe. Someone might think in the future that the String() constructor is redundant and remove it, reintroducing the crash. So guarding against the actual unnecessary comparison is safer.

[akien-mga]

I think the bug may also exist in the master branch, see this code in core/input/input.cpp:

JoyButton Input::_get_output_button(String output) {
        for (int i = 0; i < (int)JoyButton::SDL_MAX; i++) {
                if (output == _joy_buttons[i]) {
                        return JoyButton(i);
                }
        }
        return JoyButton::INVALID;
}

JoyAxis Input::_get_output_axis(String output) {
        for (int i = 0; i < (int)JoyAxis::SDL_MAX; i++) {
                if (output == _joy_axes[i]) {
                        return JoyAxis(i);
                }
        }
        return JoyAxis::INVALID;
}

[Snowapril]

@akien-mga It seems that _joy_buttons and _joy_axes limited its length with their max enum value.

static const char *_joy_buttons[(size_t)JoyButton::SDL_MAX] = {
	"a",
	"b",
	"x",
	"y",
	"back",
	"guide",
	"start",
	"leftstick",
	"rightstick",
	"leftshoulder",
	"rightshoulder",
	"dpup",
	"dpdown",
	"dpleft",
	"dpright",
	"misc1",
	"paddle1",
	"paddle2",
	"paddle3",
	"paddle4",
	"touchpad",
};
static const char *_joy_axes[(size_t)JoyAxis::SDL_MAX] = {
	"leftx",
	"lefty",
	"rightx",
	"righty",
	"lefttrigger",
	"righttrigger",
};

JoyButton::SDL_MAX and JoyAxis::SDL_MAX are exactly matched with the length of each array.
Do we also need to add an additional nullptr check for them?

[akien-mga]

JoyButton::SDL_MAX and JoyAxis::SDL_MAX are exactly matched with the length of each array.
Do we also need to add an additional nullptr check for them?

Ah that's correct, then it seems fine as is.

[akien-mga]

We don't translate error messages so this shouldn't use RTR(). (my suggestion was using C++ R-strings to avoid having to escape ", but it's fine with the escape too)

[Snowapril]

Ah,, I misunderstood your suggestion. Ok I applied it.

[akien-mga]

*an axis index

[Snowapril]

Oh I missed it. Sorry 😂

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.4.4.