为什么在 ipython 中定义 python 类方法中的信号处理程序不再有效？

Question

我有一大类数据采集方法和设置，我们通常从 ipython 终端使用它们。该类还定义了一个信号处理程序方法 cleanup，该方法应该在用户使用 KeyboardInterrupt 中断数据采集后收集所有待处理的传入数据流并干净地关闭文件（或发生其他一些不可预见的中断）。我通过 signal.signal(signal.SIG*, self.cleanup) 将此信号处理程序方法分配给相应的 signal.SIG* 信号，作为类的一部分 __init__ 方法。这在过去的大约一年中完美地发挥了作用。 5 年了，但自从几个月前全新安装 conda 环境以来似乎就被破坏了。同时，我在一些运行良好的数字或 conda 环境中复制了此内容，在更新后，此内容停止工作。

下面是一个简化的代码示例（在 interrupt_signal_handler_test.py 中定义）：

import signal
import time


class InterruptTest(object):

    def __init__(self):
        print("initializing...")

        # print the current SIGINT signal handler
        print (signal.getsignal(signal.SIGINT))

        # assign the cleanup method to the SIGINT signal handler
        signal.signal(signal.SIGINT, self.cleanup)

        # print the current SIGINT signal handler
        print (signal.getsignal(signal.SIGINT))

    def cleanup(self, sigNum, frame):
        print("cleanup was called")
        print(sigNum)
        print(frame)
        raise InterruptedError("Code was interrupted by the user")

    def run(self):
        # print the current SIGINT signal handler
        print (signal.getsignal(signal.SIGINT))
        print("Press Ctrl+C to interrupt the counting.")
        i = 1
        while(True):
            time.sleep(1.0)
            print(i)
            i += 1

首先，当直接通过 python 运行脚本时，它在两种环境中都按预期工作：

$ python interrupt_signal_handler_test.py 
<built-in function default_int_handler>
initializing...
<bound method InterruptTest.cleanup of <__main__.InterruptTest object at 0x1083a1fd0>>
<bound method InterruptTest.cleanup of <__main__.InterruptTest object at 0x1083a1fd0>>
Press Ctrl+C to interrupt the counting.
1
2
3
^Ccleanup was called
2
<frame at 0x1083aac10, file 'interrupt_signal_handler_test.py', line 25, code run>
Traceback (most recent call last):
  File "interrupt_signal_handler_test.py", line 32, in <module>
    t.run()
  File "interrupt_signal_handler_test.py", line 25, in run
    time.sleep(1.0)
  File "interrupt_signal_handler_test.py", line 18, in cleanup
    raise InterruptedError("Code was interrupted by the user")
InterruptedError: Code was interrupted by the user

现在，当运行 (run -i Interrupt_signal_handler_test.py）在“旧”环境中的 ipython 中手动执行相同的代码，我得到以下（期望的）行为：

$ print(signal.getsignal(signal.SIGINT))
<built-in function default_int_handler>

$ t = InterruptTest()
initializing...
<built-in function default_int_handler>
<bound method InterruptTest.cleanup of <__main__.InterruptTest object at 0x10e9c9df0>>

$ t.run()
<bound method InterruptTest.cleanup of <__main__.InterruptTest object at 0x10e9c9df0>>
Press Ctrl+C to interrupt the counting.
1
2
3
^Ccleanup was called
2
<frame at 0x10e9c0640, file '<ipython-input-1-d5369e70ce7e>', line 31, code run>
---------------------------------------------------------------------------
InterruptedError                          Traceback (most recent call last)
....
InterruptedError: Code was interrupted by the user

$ t.run()
<bound method InterruptTest.cleanup of <__main__.InterruptTest object at 0x10e9c9df0>>
Press Ctrl+C to interrupt the counting.
1
2
3
4
^Ccleanup was called
2
<frame at 0x7f8c6d83a000, file '<ipython-input-1-d5369e70ce7e>', line 31, code run>
---------------------------------------------------------------------------
InterruptedError                          Traceback (most recent call last)
....
InterruptedError: Code was interrupted by the user

每次我调用清理方法run() 我的实验。然而，在更新的 python 安装中，我现在得到以下信息：

$ print (signal.getsignal(signal.SIGINT))
<built-in function default_int_handler>

$ t = InterruptTest()
initializing...
<built-in function default_int_handler>
<bound method InterruptTest.cleanup of <__main__.InterruptTest object at 0x1029a04c0>>
# So far so good...

$ t.run()
<built-in function default_int_handler>
Press Ctrl+C to interrupt the counting.
1
2
^C---------------------------------------------------------------------------
KeyboardInterrupt                         Traceback (most recent call last)
Input In [5], in <cell line: 1>()
----> 1 t.run()

Input In [1], in InterruptTest.run(self)
     29 i = 1
     30 while(True):
---> 31     time.sleep(1.0)
     32     print(i)
     33     i += 1

KeyboardInterrupt: 

# Not good: The signal handler was somehow reset to the built-in one

很明显，行为发生了变化 - 无论是否是有意设计的，我无法弄清楚。这是一个已知问题吗？这是故意改变的吗？如果是的话，现在如何将自定义信号处理程序编写为类方法以与交互式使用 ipython 兼容？

另请注意，这与操作系统无关，它发生在 RHELS7 和 OSX 托管的 conda 环境中。

以下是 python 和 ipython 版本：

"old":
  - ipython=7.23.1
  - ipykernel=5.5.5
  - python=3.8.10

"new":
  - ipython=8.1.1
  - ipykernel=6.9.1
  - python=3.8.12