[issue25612] nested try..excepts don't work correctly for generators

[Serhiy Storchaka]

Serhiy Storchaka <storchaka+cpython at gmail.com> added the comment:

I tried the following code:

def g():
    yield 1
    raise
    yield 2

i = g()
try:
    1/0
except:
    next(i)
    next(i)

Currently it raises:

Traceback (most recent call last):
  File "<stdin>", line 5, in <module>
  File "<stdin>", line 2, in <module>
ZeroDivisionError: division by zero

With PR 1773 applied it raises:

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
ZeroDivisionError: division by zero

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 5, in <module>
  File "<stdin>", line 3, in g
RuntimeError: No active exception to reraise

And this looks more correct.

But if replace raise with print(sys.exc_info()) the patched and unpatched interpreters both print:

(<class 'ZeroDivisionError'>, ZeroDivisionError('division by zero',), <traceback object at 0x7f61d9ed1448>)

Is it correct that sys.exc_info() return an exception while raise can't reraise it?

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versions: +Python 3.7 -Python 3.4, Python 3.5

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<https://bugs.python.org/issue25612>
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