add_real_directory does not work after chdir

[abbec]

If I do an os.chdir() call before calling add_real_directory with an absolute path, os.listdir() on that directory returns nothing since target path is set to the combination of the current directory and the specified path to add_real_directory.

Example

os.chdir("/Users/abbe/test")
fs.add_real_directory("/Users/abbe/real")
os.listdir("/Users/abbe/real")

the call to os.listdir() returns nothing in this case since the file gets added as /Users/abbe/test/Users/abbe/real instead of /Users/abbe/real.

[mrbean-bremen]

Thanks for the report - I will have a look!

[mrbean-bremen]

So, to understand this: this is inside a unit test, or after setting up Patcher? E.g. os here is the faked version?
In this case, you already have a directory "/Users/abbe/test" in your fake file system - did you add that also using add_real_directory()?

[mrbean-bremen]

I'm trying to reproduce this, but until now it works correctly for me - so I'm obviously doing something different. I need a bit more context to be able to reproduce this...

[abbec]

Yes, this is inside a unit test/after patcher is set up (os is the faked version) and /Users/abbe/test was added to the fake filesystem with create_dir() prior to the above lines.

[abbec]

This code

import os

def test_something(fs):
    fs.create_dir("/Users/acervin/somethingfake")
    os.chdir("/Users/acervin/somethingfake")
    fs.add_real_directory("/Users/acervin/test")

    print(os.listdir("/Users/acervin/test"))
    print(os.listdir("/Users/acervin/somethingfake/Users/acervin/test"))

    assert os.listdir("/Users/acervin/test")

gives this output

and the folder /Users/acervin/test contains one file called test.txt.

[abbec]

And if I remove the call to os.chdir in the above code (effectively leaving cwd at /) it works.

[mrbean-bremen]

Ok, thanks! I will have another look in the evening.

[mrbean-bremen]

Unfortunately I couldn't reproduce this under Windows, so I think it is Unix-specific. My Ubuntu got trashed with the latest Windows 10 reinstall, and I couldn't get the grub menu to show up even after an Ubuntu reinstall, grub-update and the like, so I'm giving up for today. Got to love Windows 10...
I may have another go at the weekend.

[abbec]

Yeah, it is specific to *NIX and I think it caused by the code here: https://github.com/jmcgeheeiv/pyfakefs/blob/master/pyfakefs/fake_filesystem.py#L394. When it is normalizing it ignores the leading slash (that denotes the root) since it says names[1:]. The function absnormpath will then hit this code:

elif not self._starts_with_root_path(path):
    # Prefix relative paths with cwd, if cwd is not root.
    ...

[mrbean-bremen]

Thanks - that helped! So the real bug is in FakeDirectory.path, I just added a fix for this. Please check if this fixes your problem.

[mrbean-bremen]

I could reproduce the problem under Linux (got it running again) before the fix, it is gone now - closing.

[abbec]

Awesome thanks!