Python 3: file() function is no more

[josephsl]

Hi,

Continuing research on road blocks to Python 3 transition (see #7105 for rationale).

Is your feature request related to a problem? Please describe.

Problem: in Python 3, file() function is no more.

Steps to reproduce:

1. Run Python 2 and 3 interpreters.
2. Try the following code path:

something = file(somefilename)

python 2: works as advertised.
Python 3: name error is thrown.

This is because in python 2, file() function is really a constructor for file objects (or a stream object treated as a file). The general recommendation from various sources is to use open() function to create a file object, and close it once finished. Another way is through a context manager (with statement).

Describe the solution you'd like

The ideal solution is use of context manager syntax of the form:

with open(somefile, mode) as someMeaningfulName:
dosomething …

Note: spaces are used for indentation.

Describe alternatives you've considered

Another alternative is using the form:

something = open(somefile, mode)
code …
something.close()

Although applying this solution everywhere may sound consistent, there are cases (such as when opening and closing pickle files) where context manager syntax makes more sense.

Additional context

The solutions proposed above are both Python 2 and 3 compliant, which should assist with #7105. So far, tests with a Python 3 version of NVDA indicate that open()/code/close() will work for the most part, but some code paths may benefit from use of context manager (I would say most would).

Thanks.

[josephsl]

Hi,

The affected files are:

• source/addonHandler/init.py
• source/buildVersion.py
• source/config/init.py
• source/gui/logViewer.py
• source/logHandler.py
• source/NVDAHelper.py
• source/updateCheck.py
• source/watchdog.py
• Any module (NVDA Core or add-ons) that deals with file I/O and uses file() function

Thanks.

[feerrenrut]

Closed with #9663