cache_time handling in operations.apt module broken in pyinfra v1.4

Describe the bug

Using the ‘cache_time’ argument in apt.update() or apt.packages() causes deploy to fail with an unexpected exception.

This started after updating to pyinfra v1.4. Before that the same code ran without error.

To Reproduce

Steps to reproduce the behavior (include code & usage example):

Sample code (in file cache_time_test.py)

from pyinfra.operations import apt
SUDO = True
apt.update(name='This will succeed')
apt.update(name='This will fail', cache_time=3600)

Result

Running above code with only the first apt.update statement present (second statement commented out), apt is updated normally on host.

Running the code with ‘apt.update(cache_time=3600)’ gives the output below.

Output excerpt (personal details replaced with […]):

--> Preparing operations...
    Loading: cache_time_test.py
--> An unexpected exception occurred in: cache_time_test.py:

  File "[...]/site-packages/pyinfra_cli/util.py", line 55, in exec_file
    exec(PYTHON_CODES[filename], data)
  File "cache_time_test.py", line 8, in <module>
    apt.update(name='This will fail', cache_time=3600)
  File "[...]/site-packages/pyinfra/api/operation.py", line 365, in decorated_func
    commands = unroll_generators(func(*actual_args, **actual_kwargs))
  File "[...]/site-packages/pyinfra/api/util.py", line 192, in unroll_generators
    for item in generator:
  File "[...]/site-packages/pyinfra/operations/apt.py", line 313, in update
    cache_info['mtime'] = datetime.utcnow()
TypeError: 'NoneType' object does not support item assignment

Expected behavior

Code should run to completion, updating the apt cache once, then giving ‘apt is already up to date’ result.

Meta

• Include output of pyinfra --support.

  System: Linux Platform: Linux-5.8.0-50-generic-x86_64-with-glibc2.31 Release: 5.8.0-50-generic Machine: x86_64 pyinfra: v1.4 Executable: /path/to/venv/bin/pyinfra Python: 3.9.2 (CPython, GCC 9.3.0)

• How was pyinfra installed (source/pip)?

  pyinfra installed via pip into a venv

• Include pyinfra-debug.log (if one was created)

  No debug log created

• Consider including output with -vv and --debug.

  I didn’t think this added much except that the exception occurred right after “Loaded fact date”. After that the output is the same as above.

[Pimmelton]

Cool! Can’t wait to give it a try. Thanks!

[Pimmelton]

Thank you for spotting this @Pimmelton! Going to test / fix this ASAP!

My pleasure. Glad to contribute to this great project.