Attrs: option for disable strips the underscores

[sky-code]

Add an option to disable strips the underscores
http://www.attrs.org/en/stable/init.html#private-attributes

I need to create class with _id attribute and this is not possible with attrs at this moment

[hynek]

You can have an _id attribute just fine; it’s just the __init__ signature is going to be __init__(_id):

In [1]: import attr

In [2]: @attr.s
   ...: class C:
   ...:     _id = attr.ib()
   ...:

In [3]: C(1)
Out[3]: C(_id=1)

[sky-code]

Problem is in __init__ method

In [1]: import attr

In [2]: @attr.s
   ...: class C:
   ...:     _id = attr.ib()
   ...:

In [3]: C(**{'_id': 1})
Traceback (most recent call last):
  File "<input>", line 1, in <module>
TypeError: __init__() got an unexpected keyword argument '_id'

How to add _id as is without stripping into __init__ kwargs ?

[decentral1se]

_ stripping should be optional IMHO. I am blocked on adding a _thing to my class which also has a thing attribute (don't ask, I'm doing a source port). Even if you are right about private attributes "not existing", this choice encoded into the software seems contrary to the stated goals of not "slowing down your code".

[decentral1se]

Furthermore, the documentation states that "There really isn’t a right or wrong, it’s a matter of taste." but one way is not allowed in the software so there is clearly a wrong way to do it according to attrs. This is misleading.

[energizah]

This issue has come up in some generated code before, for example like this.

@attr.s
class A:
    _ = attr.ib()

File "<attrs generated init __main__.A>", line 2
    self._ =
             ^
SyntaxError: invalid syntax

[Jasperscheper]

Any updates on this topic?

[Tinche]

A side note, you can use cattrs to structure classes with underscore attributes:

import attr
import cattr

@attr.s
class C:
  _id = attr.ib()

cattr.structure({'_id': 1}, C)