Potential issue with multi volume pre-processing

[nflexfo]

Describe the problem:

Commit fb0a7d4 changed the error handling of preprocessor to only raise an exception when none of the sources were successfully pre-processed. However, the current implementation will actually raise an exception when the last source preprocessing failed:

https://github.com/joachimmetz/plaso/blob/ebe2f69b4903ca8a3da23ac9ad9b233664425d3e/plaso/preprocessors/interface.py#L65

    last_exception = None

    for source in artifact_definition.sources:
      if source.type_indicator not in (
          artifact_definitions.TYPE_INDICATOR_FILE,
          artifact_definitions.TYPE_INDICATOR_PATH):
        continue

      for path in source.paths:
        find_spec = file_system_searcher.FindSpec(
            case_sensitive=False, location_glob=path,
            location_separator=source.separator)

        for path_specification in searcher.Find(find_specs=[find_spec]):
          try:
            self._ParsePathSpecification(
                mediator, searcher, file_system, path_specification,
                source.separator)

            last_exception = None
          except errors.PreProcessFail as exception:
            last_exception = exception

    if last_exception:
      # Only raise an exception if none of the sources were successfully
      # pre-processed.
      raise last_exception

If I'm not mistaken, the fix would be add another variable succeed set to False and mark it True instead of last_exception = None, and then check the success value at the end of the function while raising the last_exception exception.

To Reproduce:

Pre-process two sources where the first source succeed and the second fails.

Affected Version

Any version >= Plaso-20230717.

Expected behavior:

According to commit message, the method should only raise exception if all sources have failed.

Debug output/tracebacks:

N/A

Additional context

N/A

[joachimmetz]

thanks for flagging I'll have a look when time permits, there is more work to be done on multi volume pre-processing also see #2286