Library with custom `__dir__` and attributes implemented via `__getattr__` causes crash

[JanDubcak]

Hello folks,
If I use faker library (python version) with RF7 and higher. There is an error during runtime, while importing the library.
However the library is imported successfully if RF6 is used.
Since the time to upgrade to latest and greatest has come, I have tried and found myself stuck on this issue.

RF & Python version: Robot Framework 7.2.2 (Python 3.13.2 on win32)
OS: Windows 11 Enterprise, Version: 23H2, OS build: 22631.4890, Installed on: 10. ‎7. ‎2024

Steps to reproduce:

• Install robotframework
  pip install robotframework==7.2.2
pip install faker
• Create test a case that uses faker

*** Settings ***
Library         faker.Faker    sk-SK

*** Test Cases ***
Do nothing
    Sleep    1s

• Run the test case

$ robot robot-faker.robot
[ ERROR ] Unexpected error: AttributeError: aba
Traceback (most recent call last):
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\utils\application.py", line 81, in _execute
    rc = self.main(arguments, **options)
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\run.py", line 475, in main
    result = suite.run(settings)
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\model.py", line 802, in run
    self.visit(runner)
    ~~~~~~~~~~^^^^^^^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\model\testsuite.py", line 421, in visit
    visitor.visit_suite(self)
    ~~~~~~~~~~~~~~~~~~~^^^^^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\model\visitor.py", line 128, in visit_suite
    if self.start_suite(suite) is not False:
       ~~~~~~~~~~~~~~~~^^^^^^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\suiterunner.py", line 81, in start_suite
    ns.handle_imports()
    ~~~~~~~~~~~~~~~~~^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\namespace.py", line 57, in handle_imports
    self._handle_imports(self._imports)
    ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\namespace.py", line 68, in _handle_imports
    self._import(item)
    ~~~~~~~~~~~~^^^^^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\namespace.py", line 76, in _import
    action(import_setting)
    ~~~~~~^^^^^^^^^^^^^^^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\namespace.py", line 124, in _import_library
    lib = IMPORTER.import_library(name, import_setting.args,
                                  import_setting.alias, self.variables)
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\importer.py", line 54, in import_library
    lib.create_keywords()
    ~~~~~~~~~~~~~~~~~~~^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\testlibraries.py", line 326, in create_keywords
    StaticKeywordCreator(self, avoid_properties=True).create_keywords()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\testlibraries.py", line 373, in create_keywords
    kw = self._create_keyword(instance, name)
  File "C:\Users\jan.dubcak\robot-faker\robot-faker\Lib\site-packages\robot\running\testlibraries.py", line 460, in _create_keyword
    candidate = inspect.getattr_static(instance, name)
  File "C:\Users\jan.dubcak\AppData\Local\Programs\Python\Python313\Lib\inspect.py", line 1863, in getattr_static
    raise AttributeError(attr)
AttributeError: aba

• Downgrade to RF 6.1.1
  pip install robotframework==6.1.1
• Run the test case again

$ robot robot-faker.robot
==============================================================================
Robot-Faker
==============================================================================
Do nothing                                                            | PASS |
------------------------------------------------------------------------------
Robot-Faker                                                           | PASS |
1 test, 1 passed, 0 failed
==============================================================================
Output:  C:\Users\jan.dubcak\robot-faker\output.xml
Log:     C:\Users\jan.dubcak\robot-faker\log.html
Report:  C:\Users\jan.dubcak\robot-faker\report.html

Kind thanks for anyone looking at this,
Jan.

[pekkaklarck]

I can reproduce the problem. It's caused by commit 523d9db that fixed #4915 (and caused regression #4941). The exception happens when the code looking for keywords does inspect.getattr_static(library, name) where name has earlier been got by using dir(library). My guess is that Faker has a custom __dir__ that returns items that it doesn't actually has as its attributes. That would be rather odd, but nevertheless should handle the situation.

Fixing the problem is easy, but the fix needs to wait for RF 7.3. If we end up creating another RF 7.2.x release, the fix can be backported there as well. Until that you can use the FakerLibrary, a dedicated Robot Framework library using Faker, that shouldn't have this problem.

[JanDubcak]

Thanks for the reply, I will try look into swapping faker for robotframework-faker and if it is simple replace I will do that till 7.3 milestone.

[pekkaklarck]

It actually seems Faker implements attributes somehow dynamically so that inspect.getattr_static() doesn't find them:

>>> fake = faker.Faker()
>>> fake.aba()
'084461966'
>>> getattr(fake, 'aba')
<bound method Provider.aba of <faker.providers.bank.en_GB.Provider object at 0x7f778f0d6e90>>
>>> inspect.getattr_static(fake, 'aba')
Traceback (most recent call last):
  File "<python-input-23>", line 1, in <module>
    inspect.getattr_static(fake, 'aba')
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/usr/lib/python3.13/inspect.py", line 1863, in getattr_static
    raise AttributeError(attr)
AttributeError: aba

This means that just catching AttributeError and ignoring these names isn't a proper fix. Need to investigate this more when I have time,

[pekkaklarck]

The problem is caused by Faker having a custom __dir__ and some of its attributes being implemented using __getattr__. The latter makes these attributes dynamic and thus getattr_static doesn't find them. We use it in two places and this situation needs to be taken into account in both.

Because this causes a hard crash, the issue is rather severe. It's pretty close to be severe enough to warrant RF 7.2.3 release, but because the bug appeared in RF 7.0 that was released over a year ago and nobody reported it earlier, I don't think it causes problems too often. In this particular case using FakerLibrary is also an acceptable workaround. Anyway, if we need RF 7.2.3 for other reasons, this fix definitely needs to be backported to it.