Add Unofficial.Microsoft.Unity.Analyzers nuget package

[DaEgi01]

edited by @aubergine10

Unity breaks how null works...

Specifically:

// UnityEngine.Object
public static bool operator ==(Object x, Object y)
{
	return CompareBaseObjects(x, y);
}

// UnityEngine.Object
public static implicit operator bool(Object exists)
{
	return !CompareBaseObjects(exists, null);
}

// UnityEngine.Object
public static bool operator !=(Object x, Object y)
{
	return !CompareBaseObjects(x, y);
}

// UnityEngine.Object
private static bool CompareBaseObjects(Object lhs, Object rhs)
{
	bool flag = (object)lhs == null;
	bool flag2 = (object)rhs == null;
	if (flag2 && flag)
	{
		return true;
	}
	if (flag2)
	{
		return !IsNativeObjectAlive(lhs);
	}
	if (flag)
	{
		return !IsNativeObjectAlive(rhs);
	}
	return lhs.m_InstanceID == rhs.m_InstanceID;
}

This means that != null, ?. and ?? no longer mean what we think they mean when used on anything based on UnityEngine.Object.

The Microsoft.Unity.Analyzers package (specifically UNT0007 and UNT0008) warns when ?. and ?? are used on something derived from UnityEngine.Object.

Note, however, it does not currently warn about != null issues.

When testing a UE.Object replace:

if (something != null) ...

With:

if (!something) ...

More reliable/comprehensible alternatives might be:

(object)obj == null

// or...

Object.ReferenceEquals(myGameObj, null)

[originalfoo]

^ Updated OP with detailed info of the specific things we are hoping to tackle with the analyzer, and also clarify one case the analyzer doesn't currently detect (but is being considered - see: microsoft/Microsoft.Unity.Analyzers#79 )

[krzychu124]

👍
JB Rider has built-in similar feature (just an example, ModUI is MonoBehaviour)

[DaEgi01]

what about
x is null, I would go for that option if possible since its "normal" c#.

[originalfoo]

if x is null check works, then yes that would be my preferred option.

[originalfoo]

LGTM 👍