M5Stack LED doesn't initialize GPIO leading to errors

[jacobguilbeau]

Library/API/IoT binding

M5StickCPlus

Visual Studio version

VS2019 (16.11.16)

.NET nanoFramework extension version

2019.11.0.23

Target name(s)

M5StickCPlus.led.Toggle()

Firmware version

1.8.0.458

Device capabilities

No response

Description

Trying to run a simple one line statement to toggle the LED fails with CLR_E_NULL_REFERENCE

Code trying to run:
M5StickCPlus.Led.Toggle();

Produces this output:
The thread '<No Name>' (0x2) has exited with code 0 (0x0). ++++ Exception System.NullReferenceException - CLR_E_NULL_REFERENCE (1) ++++ ++++ Message: ++++ nanoFramework.M5Stack.M5StickCPlus::get_Led [IP: 000e] ++++ ++++ NFApp2.Program::Main [IP: 0004] ++++ Exception thrown: 'System.NullReferenceException' in nanoFramework.M5StickCPlus.dll An unhandled exception of type 'System.NullReferenceException' occurred in nanoFramework.M5StickCPlus.dll

This is due to the led object depending on a gpio internal object that has not been created. Getting the GPIOController forces the internal object to be created leading to the led object now working correctly.

How to reproduce

1. Start new nanoframework project
2. Try and do anything with M5StickCPlus.Led

Expected behaviour

I expect the led to toggle without exception

Screenshots

No response

Sample project or code

No response

Aditional information

Problem is here:
https://github.com/nanoframework/nanoFramework.M5Stack/blob/31c8cf98ba5b458485d41235fe7f0ce50681b955/nanoFramework.M5StickCommon/M5StickCBase.cs#L28

led get just returns _gpio. and doesn't check for null or create a new gpio.

[josesimoes]

This is using a lazy load pattern. It's been fixed in several other M5stack devices.
Can you take a look and submit a PR with a fix? 😁 That would be great!

[jacobguilbeau]

Yes! I'll look at what the other devices are doing here and duplicate.

[jacobguilbeau]

Looks like I can replace the usage of _gpio in the leds and buttons with GPIOController and this will instantiate it if needed - does that sound ok?

[josesimoes]

Better keep the existing organization, there are shared classes (for example) and other code using the gpio controller and pins.
Check nanoframework/nanoFramework.M5Stack#193 for insipiration.

[jacobguilbeau]

Yes, I see what you are doing there. I'm saying that replacing:

with

seems to be the proper way to go, no? That way it uses the loader properly. There are some files, like M5Stack.Fire.cs where _gpio = new(). Should I redo that like #193 to support the lazy loading model being used everywhere else? I can create a new issue for that.