Alternative #2 to gh-733, fixing spurious warnings. #742
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…by a misunderstanding of how __new__ works
In those patches, I declared classes that were roughly
```python
class SomeClass:
def __new__(cls, arg):
try:
return existing[arg]
except KeyError:
return super(SomeClass, cls).__new__(cls, arg)
def __init__(self, arg):
self.arg = arg
self.state = 0
```
This approach has a fatal flaw (cocotbgh-729), with function calls shown in the following code:
```python
A = SomeClass(1)
# SomeClass.__new__(SomeClass, 1) -> A
# A.__init__(1)
B = SomeClass(1)
# SomeClass.__new__(SomeClass, 1) -> A # reusing the existing instance
# A.__init__(1) # uh oh, we reset A.state
```
For the sake of simplicity, this commit undoes the merger between the factory functions and the classes themselves, while keeping the weakref behavior.
In future, it would be good to explore the more complex approach taken in cocotbgh-733, which ensures that `isinstance(Join(), Join)`, which this patch does not.
Since this property was not true before cocotbgh-723 and cocotbgh-727 anyway, we can afford to revert that improvement in order to get a release out the door.
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We took #733 now, thanks for your fantastic work @eric-wieser! It's really rare to see so much dedication at work; be sure to ask for a $PREFERRED_DRINK if we ever meet at a conference or elsewhere. |
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For the sake of simplicity, this commit undoes the merger between the factory functions and the classes themselves, while keeping the weakref behavior.
In future, it would be good to explore the more complex approach taken in gh-733, which ensures that
isinstance(Join(), Join), which this patch does not.Since this property was not true before gh-723 and gh-727 anyway, we can afford to revert that improvement in order to get a release out the door.