The `exit()` [1] function is not necessarily present in every Python
environment, as it's added by the `site` module. Also, this function is
"[...] useful for the interactive interpreter shell and should not be
used in programs"
For this reason, we replace all such occurrences with `sys.exit()` [2],
which is the canonical function to exit Python programs.
[1]: https://docs.python.org/3/library/constants.html#exit
[2]: https://docs.python.org/3/library/sys.html#sys.exit
Due to a bump in our Python dependencies, we now install Mypy 1.1.1
instead of 0.982. This change triggered the following errors:
* Incompatible default for argument <a> (default has type
None, argument has type <t>):
Mypy further explains here that PEP 484 prohibits implicit Optional,
so we need to make these types explicit Optional.
* Unused "type: ignore" comment, use narrower [method-assign] instead of
[assignment]:
Mypy has specialized some of its lints, meaning that we should switch
to the newer variants.
Also, it detected several other small inconsistencies. We fix all of
these errors in this commit.
Wildcard arguments like `*` can lead to security vulnerabilities
if files are maliciously named as would-be parameters. In the following
scenario if a file in the current directory was named '--help', running
the following command would show the help.
$ dangerzone-cli *
By checking if parameters also happen to be files, we mitigate this
risk and have a chance to warn the user.
Make the Document class always resolve relative input/output file paths,
which are usually passed as arguments by users.
Previously, resolving relative filepaths was a job left to the
instantiators of the Document class. This was error-prone since this
conversion must happen in all the places where we instantiated the
Document class.
Implement Click's callback interface and create validators for the
input/output filenames, using the logic from the Document class. This
way, we can catch user errors as early as possible.
