Gabriel C <gabri...@mit.edu> added the comment:
Some further investigation suggests this may have nothing to do with pickle at
all.
Consider the following short example:
```
def CreateDynamicClass(basetype):
class DynamicClassImpl(basetype):
def __init__(self):
super(DynamicClassImpl, self).__init__()
return DynamicClassImpl()
# Comment out any of the following three lines and the test passes
dynamic_memerror = CreateDynamicClass(MemoryError)
memory_error = MemoryError("Test")
dynamic_memerror = CreateDynamicClass(MemoryError)
print(MemoryError("Test2"))
```
This reliably produces the following stack trace:
```
Traceback (most recent call last):
File "test_min2.py", line 13, in <module>
print(MemoryError("Test2"))
TypeError: __init__() takes 1 positional argument but 2 were given
```
In addition it causes a bus error (signal 10) around 30% of the time when run
on python 3.7.4 (macOS high sierra) and a segmentation fault around 10% of the
time when run on python 3.5 (Ubuntu 16.04).
Now modify the short example as follows, inserting a dummy argument into the
constructor of the dynamic exception type:
```
def CreateDynamicClass(basetype):
class DynamicClassImpl(basetype):
def __init__(self, dummy_arg):
if dummy_arg is not None:
raise AssertionError("Dynamic exception constructor called.")
super(DynamicClassImpl, self).__init__()
return DynamicClassImpl(None)
# Comment out any of the following three lines and the test passes
dynamic_memerror = CreateDynamicClass(MemoryError)
memory_error = MemoryError("Test")
dynamic_memerror = CreateDynamicClass(MemoryError)
print(MemoryError("Test2"))
```
This produces the following stack trace:
```
Traceback (most recent call last):
File "test_min2.py", line 15, in <module>
print(MemoryError("Test2"))
File "test_min2.py", line 5, in __init__
raise AssertionError("Dynamic exception constructor called.")
AssertionError: Dynamic exception constructor called.
```
showing that the user-defined type constructor is actually called when the
MemoryError object is created.
----------
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Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue37997>
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