臭虫System.Random构造？ [英] Bug in System.Random constructor?

问题描述

的 System.Threading.ConcurrentQueue.TryDequeue 方法抛出异常，那天我花了完全措手不及。这里的堆栈跟踪：

The System.Threading.ConcurrentQueue.TryDequeue method threw an exception the other day that took me totally by surprise. Here's the stack trace:

System.OverflowException: Negating the minimum value of a twos complement number is invalid.
   at System.Math.AbsHelper(Int32 value)
   at System.Random..ctor(Int32 Seed)
   at System.Threading.Collections.ConcurrentQueue`1.TryDequeueCore(T& result)
   at System.Threading.Collections.ConcurrentQueue`1.TryDequeue(T& result)
   at MyProgram.ThreadProc() in c:\MyProgram\Main.cs:line 118
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

起初我以为，问题是， TryDequeueCore 名为随机构造函数一个坏的值。但进一步调查发现， TryDequeueCore 调用默认的构造函数。它看起来对我来说，错误是在随机构造器：

At first I thought the problem was that TryDequeueCore called the Random constructor with a bad value. But further investigation reveals that TryDequeueCore calls the default constructor. It looks to me like the error is in the Random constructor:

.method public hidebysig specialname rtspecialname 
        instance void  .ctor() cil managed
{
  // Code size       12 (0xc)
  .maxstack  8
  IL_0000:  ldarg.0
  IL_0001:  call       int32 System.Environment::get_TickCount()
  IL_0006:  call       instance void System.Random::.ctor(int32)
  IL_000b:  ret
} // end of method Random::.ctor

对于系统的文档。 Environment.TickCount 属性说：

此属性的价值是衍生
从系统计时器并存储为
A 32位有符号整数。因此，如果系统持续运行，

计时单位计数将从零增加至
的Int32 .. ::。MaxValue的约
24.9天，然后跳转到的Int32 .. :: .MinValue，这是一个
负数，则在接下来的24.9天递增背面
键零

The value of this property is derived from the system timer and is stored as a 32-bit signed integer. Consequently, if the system runs continuously, TickCount will increment from zero to Int32..::.MaxValue for approximately 24.9 days, then jump to Int32..::.MinValue, which is a negative number, then increment back to zero during the next 24.9 days.

所以，如果你打电话期间1毫秒周期随机构造函数（该系统已经运行了之后 int.MaxValue 毫秒），这将抛出此异常。

So, if you call the Random constructor during that one-millisecond period (after the system has been up for int.MaxValue milliseconds), it's going to throw this exception.

有谁有解决方法吗？对于我自己的代码，我可以做一个 CreateRandom 方法获取计时单位计数值，并检查它 int.MinValue 。但是，该怎么做，我无法控制的代码？

Does anybody have a workaround? For my own code, I can make a CreateRandom method that gets the TickCount value and checks it for int.MinValue. But what to do about code that I have no control over?

我希望RTL队修复了这个在.NET 4.0中。

I hope the RTL team fixes this in .NET 4.0.

更新2009/07/22：首创置业团队回应了错误，并表示，它已经解决了下一个版本

Update 2009/07/22: The BCL Team responded to the bug and said that it has been resolved for the next release.

推荐答案

尝试 / 抓，然后重试毫秒后，似乎只是你可以做，直到唯一这个bug确实拿不动。

try/catch and retry a millisecond later seems just about the only thing you can do until this bug does get fixed.

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