refactor: add type hints in version_scanner.py

[rhythmrx9]

part of #1539

[Molkree]

Untyped:

cve-bin-tool/cve_bin_tool/version_scanner.py

Line 358 in 3c716e5

results = [dict()]

I don't understand why it has different values in two if branches...

[Molkree]

Why is it type[Checker] and not just Checker? 🤔

[rhythmrx9]

Because its the Checker subclass itself (uninstantiated) of type CheckerMetaClass.

cve-bin-tool/cve_bin_tool/version_scanner.py

Lines 353 to 354 in 3c716e5

	for (dummy_checker_name, checker) in self.checkers.items():
	checker = checker()

[rhythmrx9]

Untyped:

cve-bin-tool/cve_bin_tool/version_scanner.py

Line 358 in 3c716e5

results = [dict()]

I don't understand why it has different values in two if branches...

I am confused there as well, I don't think we need the for loop under as well.

Do we need this part?

cve-bin-tool/cve_bin_tool/version_scanner.py

Lines 348 to 354 in ab07fb9

	if "is_or_contains" in result:
	results = [dict()]
	results[0] = result
	else:
	results = result
	for result in results:

Tried to remove it, long tests for kerberos checker failed.
Some checkers override get_version method and return list of dictionaries(e.g. kerberos), we do need above part.
That is why results has different values.

[terriko]

This is not very self explanatory. It needs documentation, or perhaps we need some appropriately named custom types to make this clearer.

[rhythmrx9]

I will make it a custom type like ProductInfo, hope that makes it clearer.

[terriko]

I think we might want to do some additional refinement with custom types, but this looks good enough to merge now. Thank you!