Thanks for the contribution.

Here are a few concerns about this patch (and the issue too).

• It seems it is not defined in document. https://docs.python.org/3/library/sys.html Please share if you know any use case of this attribute.
• It seems it is expected to refer actual python framework (which is linked?). My pyenv python build in macos have just empty string. Probably this must be just empty string because RustPython is never built as Python.framework.

➜  ~ python
Python 3.7.0 (default, Aug 24 2018, 13:00:59)
[Clang 9.1.0 (clang-902.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.framework
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'sys' has no attribute 'framework'
>>> sys._framework
''

• Writing a test code is recommended
• This patch defines the attribute for all platforms. It seems it is not defined out of macOS. Check #[cfg(target_os = "macos")] and extend_class! for optional attribute.

➜  ~ python
Python 3.6.3 (default, Oct 12 2017, 21:12:06)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
p>>> import sys
>>> sys._framework
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'sys' has no attribute '_framework'
>>>

@youknowone

Thank you for comment.

Currently this code only affects the site module. Where to use:

CPython also uses the sysconfig module. This is the same code as _getuserbase() in the site module.

    if sys.platform == "darwin" and sys._framework:
        return joinuser("~", "Library", sys._framework,
                        "%d.%d" % sys.version_info[:2])

site.getuserbase() returns the user base directory.

This function works as follows on my system:

$ python3     # is system python
[Clang 10.0.1 (clang-1001.0.46.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import site
>>> site.getuserbase()
'/Users/vazrupe/Library/Python/3.7'
>>> import sys
>>> sys._framework
'Python'

$ pyenv shell 3.7.0
$ python
Python 3.7.0 (default, Sep  7 2019, 14:41:54)
[Clang 10.0.1 (clang-1001.0.46.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import site
>>> site.getuserbase()
'/Users/vazrupe/.local'
>>> import sys
>>> sys._framework
''

As you commented, this value seems to be an empty string. In such a case, the following value will always be returned.

And this attribute is defined on all platforms. However, it is only implemented in 3.7+ and up, so it cannot be used in lower versions.

For example, in my windows(anaconda 3.7.3) environment it would run:

PS> python
Python 3.7.3 (default, Apr 24 2019, 15:29:51) [MSC v.1915 64 bit (AMD64)] :: Anaconda, Inc. on win32

Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys._framework
''

In a Mac(use pyenv 3.6.6) environment, it runs like this:

$ pyenv shell 3.6.6
$ python
Python 3.6.6 (default, Sep  7 2019, 14:35:29)
[GCC 4.2.1 Compatible Apple LLVM 10.0.1 (clang-1001.0.46.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys._framework
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'sys' has no attribute '_framework'

Thanks for reading!

Thanks for detailed explanation. I am sorry to confuse it.

It seems CI fails because RustPython CI now tests only with CPython 3.6.
Instead of testing private attributes, how about testing site.py feature which uses _framework attribute?

I apologize for writing the wrong test case first. For RustPython developers using mac, this test may fail even with Python 3.7+. Actually this test fails on my Mac.

This is because the system python on Mac is built with Python.framework. So test code should look like this:

assert sys._framework == "" or sys._framework == "Python"

I thought about testing in the site module, but I didn't think of a good way. 😢 Also, the method does not seem to be suitable for solving this problem.

There are a few things to think about for this test.

• We expect RustPython's sys._framework to be built with an empty string.
• If running on system python on Mac, sys._framework can be 'Python'.
• Since this attribute is implemented in python 3.7+, an earlier version will throw an AttributeError.

The best code I can think of is this:

try:
    assert sys._framework == ""
except AttributeError:
    assert "%d.%d" % sys.version_info[:2] < "3.7"
except AssertionError:
    assert sys.platform == "darwin" and sys._framework == "Python"

What do you think about this solution?

now, actually, the code itself looks totally fine. but not sure the test code is fit for the goal of snippet tests.
@coolreader18 how do you think about the test code?