UnityCoroutineBugTest.cs

using UnityEngine;
using System.Collections;

public class CoroutineBugTest
    : MonoBehaviour
{
    public IEnumerator OuterReturnIEnumerator(string s)
    {
        Debug.LogFormat("Outer: enter: {0}", s);
        yield return Inner(s);
    }

    public IEnumerator OuterManualIteration(string s)
    {
        Debug.LogFormat("Outer: enter: {0}", s);
        var e = Inner(s);
        while (e.MoveNext())
        {
            yield return e.Current;
        }
    }

    public IEnumerator Inner(string s)
    {
        Debug.LogFormat("Inner: enter: {0}", s);
        while (true)
        {
            Debug.LogFormat("Inner: loop: {0}", s);
            yield return new WaitForSeconds(1.0f);
        }
    }

    void Start()
    {
        StartCoroutine(Test());
    }

    public IEnumerator Test()
    {
        var outerA = OuterReturnIEnumerator("A");
        var outerB = OuterManualIteration("B");
        var inner = Inner("C");

        StartCoroutine(outerA);
        StartCoroutine(outerB);
        StartCoroutine(inner);

        Debug.Log("CoroutineBugTest.Test(): starting...");

        yield return new WaitForSeconds(2.5f);

        // wont stop
        Debug.Log("CoroutineBugTest.Test(): stopping A");
        StopCoroutine(outerA);
        yield return new WaitForSeconds(0.1f);

        // will stop
        Debug.Log("CoroutineBugTest.Test(): stopping B");
        StopCoroutine(outerB);
        yield return new WaitForSeconds(0.1f);

        // will stop
        Debug.Log("CoroutineBugTest.Test(): stopping C");
        StopCoroutine(inner);
        yield return new WaitForSeconds(0.1f);
    }
}