Add check for an empty issue file before trying to read the line for NOLINT.

To see how this fixes an issue run the new unit tests against the main branch. Here are the steps I used.

git checkout exceptions-nolint-empty-log
git checkout main
git checkout -b x
git checkout exceptions-nolint-empty-log -- tests/exceptions/test_exceptions.py tests/exceptions/config/rsc/empty.log
python3 -m pytest tests/exceptions/test_exceptions.py

That should give you errors like the following.

collected 19 items                                                                                                                   

tests/exceptions/test_exceptions.py ................F..                                                                        [100%]

============================================================== FAILURES ==============================================================
________________________________________________ test_filter_issues_nolint_empty_log _________________________________________________

    def test_filter_issues_nolint_empty_log():
        """
        Test that NOLINT excpetions to issues do not fail with an empty issue log file.

        Expected result: same number of original issues in filtered issues
        """
        exceptions = Exceptions(
            os.path.join(os.path.dirname(__file__), "valid_exceptions.yaml")
        )

        filename = os.path.join(os.path.dirname(__file__), "config") + "/rsc" + "/empty.log"
        line_number = "0"
        tool = "dummy_tool"
        issue_type = "dummy_issue_type"
        severity = "0"
        message = "dummy_message"
        tool_issue = Issue(filename, line_number, tool, issue_type, severity, message, None)
        issues = {}
        issues["dummy_tool"] = [tool_issue]

>       filtered_issues = exceptions.filter_nolint(issues)

tests/exceptions/test_exceptions.py:362: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <statick_tool.exceptions.Exceptions object at 0x7fd5e9056df0>
issues = {'dummy_tool': [Issue(filename='/home/thomas/src/statick/statick/tests/exceptions/config/rsc/empty.log', line_number='0', tool='dummy_tool', issue_type='dummy_issue_type', severity='0', message='dummy_message', cert_reference=None)]}

    def filter_nolint(self, issues: Dict[str, List[Issue]]) -> Dict[str, List[Issue]]:
        """Filter out lines that have an explicit NOLINT on them.

        Sometimes the tools themselves don't properly filter these out if there is a
        complex macro or something.
        """
        for tool, tool_issues in list(issues.items()):
            warning_printed: bool = False
            to_remove: List[Issue] = []
            for issue in tool_issues:
                if not os.path.isabs(issue.filename):
                    if not warning_printed:
                        self.print_exception_warning(tool)
                        warning_printed = True
                    continue
                with open(issue.filename, encoding="utf-8") as fid:
                    lines = fid.readlines()
                line_number = int(issue.line_number) - 1
>               if line_number < len(lines) and "NOLINT" in lines[line_number]:
E               IndexError: list index out of range

statick_tool/exceptions.py:201: IndexError

At the end of this local test you can stash the changes and delete the temporary x branch.

sscpac / statick

Add check for an empty issue file before trying to read the line for NOLINT. #467

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