Empty filename fallback inconsistency (processors.py:79, processors.py:134, documents.py:126)

All three callers use the same pattern:
candidate_filenames = get_filename_aliases(filename) or [filename]

When filename="", get_filename_aliases("") returns [], so the or kicks in and produces [""] — a search/delete for an empty-string filename. The function's [] return for empty input was meant as an early-exit guard, but the callers undo it.

Suggested fix — remove the early-exit in file_utils.py:110-112 and instead handle it at the function level by always including the original:

  def get_filename_aliases(filename: str) -> list[str]:                                                                                                                                                                                          
      normalized = (filename or "").strip()                                  
      if not normalized:                                                                                                                                                                                                                         
          return [filename] if filename else []  # caller gets original back, not []
                                                                                                                                                                                                                                                 
      aliases = [normalized]                                                 
      ...                 

Or, simpler — document that callers should never pass an empty filename and add an assert in dev mode.

Good catch. I addressed the empty filename issue, but at the call sites rather than by changing get filename aliases return semantics.

get filename aliases still returns [] for empty or whitespace input (guard remains).
The problematic behavior came from callers doing get filename aliases(filename) or [filename], which could turn empty input into [""].

I removed that fallback in the affected paths and now handle empty alias lists explicitly:

TaskProcessor.check filename exists() returns False when aliases are empty.
TaskProcessor.delete document by filename() no ops (with log) when aliases are empty.
api/documents.check filename exists() returns { "exists": false } early when aliases are empty.
This avoids empty string OpenSearch queries while keeping get filename aliases() focused on normalized alias generation.