[New-bugs-announce] [issue34536] Enum._missing_ doesn't raise TypeError when a non-Enum object is a returned

[Paul Pinterits]

New submission from Paul Pinterits <rawing7 at gmail.com>:

In a conversation with Ethan Furman (the author of the enum module) I've been informed that Enum automatically checks whether the _missing_ method has returned an instance of the correct class, and raises a TypeError if not. (Link: https://stackoverflow.com/a/52064774/1222951)

However, this simply does not happen.

```
import enum

class MyEnum(enum.Enum):
    FOO = "foo"

    @classmethod
    def _missing_(cls, value):
        return 5

print(MyEnum('bar'))  # output: 5
```

----------
components: Library (Lib)
messages: 324282
nosy: Paul Pinterits
priority: normal
severity: normal
status: open
title: Enum._missing_ doesn't raise TypeError when a non-Enum object is a returned
type: behavior
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue34536>
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