feat: Auto Instrumentation for Awake

[bitsandfoxes]

The idea is to start and finish spans automatically for every Awake method in all MonoBehaviour within the project.
Noticeable pitfall: Not every MonoBehaviour implements Awake.

The plan:

• Hook up to the compilation pipeline to get the Assembly-CSharp.dll
• Add options flag to enable/disable feature and put it on the window
• Insert Start Span as the very first instruction
• Insert Finish Span before every return
• Enable Trace Sample Rate for smoke testing
• Enable Performance Auto Instrumentation for smoke testing
• Smoke test looking for a app.start transaction
• Smoke test looking for awake span

How it works right now:

We look for any Awake in any class within Assembly-CSharp.dll that inherits from MonoBehaviour.
I.e.

public class MyMonoBehaviour : MonoBehaviour
{
    private void Awake()
    {
        Debug.Log("This is an Awake call!");
    }
}

and we modify it to look like

public class MyMonoBehaviour : MonoBehaviour
{
    private void Awake()
   {
       SentrySdk.GetSpan()?.StartChild("awake", $"MyMonoBehaviour on {gameObject.name}");
 
       Debug.Log("This is an Awake call!");
 
       SentrySdk.GetSpan()?.Finish(SpanStatus.Ok);
   }
}

The IL code for the original

.method private hidebysig
    instance void Awake () cil managed
{
    // Method begins at RVA 0x2120
    // Header size: 1
    // Code size: 11 (0xb)
    .maxstack 8
 
    // Debug.Log("This is an Awake call!");
    IL_0000: ldstr "This is an Awake call!"
    IL_0005: call void [UnityEngine.CoreModule]UnityEngine.Debug::Log(object)
    // }
    IL_000a: ret
} // end of method MyMonoBehaviour::Awake

And the modified IL code

.method private hidebysig
 
    instance void Awake () cil managed
{
    // Method begins at RVA 0x22b7
    // Header size: 1
    // Code size: 32 (0x20)
    .maxstack 8
 
    // SentryMonoBehaviour.Instance.StartAwakeSpan(this);
    IL_0000: call class [Sentry.Unity]Sentry.Unity.SentryMonoBehaviour [Sentry.Unity]Sentry.Unity.SentryMonoBehaviour::get_Instance()
    IL_0005: ldarg.0
    IL_0006: callvirt instance void [Sentry.Unity]Sentry.Unity.SentryMonoBehaviour::StartAwakeSpan(class [UnityEngine]UnityEngine.MonoBehaviour)
    // Debug.Log("This is an Awake call!");
    IL_000b: ldstr "This is an Awake call!"
    IL_0010: call void [UnityEngine.CoreModule]UnityEngine.Debug::Log(object)
    // SentryMonoBehaviour.Instance.FinishAwakeSpan();
    IL_0015: call class [Sentry.Unity]Sentry.Unity.SentryMonoBehaviour [Sentry.Unity]Sentry.Unity.SentryMonoBehaviour::get_Instance()
    IL_001a: call instance void [Sentry.Unity]Sentry.Unity.SentryMonoBehaviour::FinishAwakeSpan()
    // }
    IL_001f: ret
} // end of method MyMonoBehaviour::Awake

[github-actions]

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against 6b08bf1

[mattjohnsonpint]

This feels strange. The comments talk about skipping sessions, but really you're skipping everything until you get a transaction. As long a there are less than 10 of them... 🤔

[mattjohnsonpint]

Generally looks good. Commented with some minor nits.

Didn't test it out though - I'd need more context.