def prune_staging_area()

in detection_rules/devtools.py [0:0]

• 27 lines of code
• 12 McCabe index (conditional complexity)

def prune_staging_area(target_stack_version: str, dry_run: bool, exception_list: str):
    """Prune the git staging area to remove changes to incompatible rules."""
    exceptions = {
        "detection_rules/etc/packages.yaml",
    }
    exceptions.update(exception_list.split(","))

    target_stack_version = Version.parse(target_stack_version, optional_minor_and_patch=True)

    # load a structured summary of the diff from git
    git_output = subprocess.check_output(["git", "diff", "--name-status", "HEAD"])
    changes = [GitChangeEntry.from_line(line) for line in git_output.decode("utf-8").splitlines()]

    # track which changes need to be reverted because of incompatibilities
    reversions: List[GitChangeEntry] = []

    for change in changes:
        if str(change.path) in exceptions:
            # Don't backport any changes to files matching the list of exceptions
            reversions.append(change)
            continue

        # it's a change to a rule file, load it and check the version
        for rules_dir in RULES_CONFIG.rule_dirs:
            if str(change.path.absolute()).startswith(str(rules_dir)) and change.path.suffix == ".toml":
                # bypass TOML validation in case there were schema changes
                dict_contents = RuleCollection.deserialize_toml_string(change.read())
                min_stack_version: Optional[str] = dict_contents.get("metadata", {}).get("min_stack_version")

                if min_stack_version is not None and \
                        (target_stack_version < Version.parse(min_stack_version, optional_minor_and_patch=True)):
                    # rule is incompatible, add to the list of reversions to make later
                    reversions.append(change)
                break

    if len(reversions) == 0:
        click.echo("No files restored from staging area")
        return

    click.echo(f"Restoring {len(reversions)} changes from the staging area...")
    for change in reversions:
        change.revert(dry_run=dry_run)