From 6ec231db9d419a760a92dbdd347778237f583a58 Mon Sep 17 00:00:00 2001
From: Wang Yu <wangyu@makeblock.cc>
Date: Fri, 12 May 2017 14:01:37 +0800
Subject: [PATCH] Fix the next thread is skipped after clone deleted

Problem:
When a clone is deleted, its thread is removed from the thread
list; but the index "i" in the execution for-loop will still +1,
making the next thread skipped.

Changes:
Added a flag "isKilled" on a thread;
Set the flag when a thread is removed from the thread list;
reduce the "i" counter if the thread of the current loop is removed.
---
 src/engine/runtime.js   | 1 +
 src/engine/sequencer.js | 3 +++
 src/engine/thread.js    | 6 ++++++
 3 files changed, 10 insertions(+)

diff --git a/src/engine/runtime.js b/src/engine/runtime.js
index 34c008a1..7f75f952 100644
--- a/src/engine/runtime.js
+++ b/src/engine/runtime.js
@@ -590,6 +590,7 @@ class Runtime extends EventEmitter {
                 continue;
             }
             if (this.threads[i].target === target) {
+                this.threads[i].isKilled = true;
                 this._removeThread(this.threads[i]);
             }
         }
diff --git a/src/engine/sequencer.js b/src/engine/sequencer.js
index c8051c87..d5c79eae 100644
--- a/src/engine/sequencer.js
+++ b/src/engine/sequencer.js
@@ -69,6 +69,9 @@ class Sequencer {
                     // Normal-mode thread: step.
                     this.stepThread(activeThread);
                     activeThread.warpTimer = null;
+                    if (activeThread.isKilled) {
+                        i--;    // if the thread is removed from the list (killed), do not increase index
+                    }
                 }
                 if (activeThread.status === Thread.STATUS_RUNNING) {
                     numActiveThreads++;
diff --git a/src/engine/thread.js b/src/engine/thread.js
index 208ff1e9..3b8ce32b 100644
--- a/src/engine/thread.js
+++ b/src/engine/thread.js
@@ -30,6 +30,12 @@ class Thread {
          */
         this.status = 0; /* Thread.STATUS_RUNNING */
 
+        /**
+         * Whether the thread is killed in the middle of execution.
+         * @type {boolean}
+         */
+        this.isKilled = false;
+
         /**
          * Target of this thread.
          * @type {?Target}