RenameFile: OSError 'File name too long' from doubled extension in long-filename truncation

[garfolino]

Plugin

RenameFile

Description

Renaming a scene whose generated filename exceeds max_filename_length (default 255) can produce a filename that is longer than the original and ends in a doubled extension (e.g. ....mp4.mp4), causing the OS rename to fail with OSError: [Errno 63] File name too long on macOS (and the equivalent ENAMETOOLONG elsewhere).

Root cause

In rename_scene() (renamefile.py), the truncate-and-hash fallback appends the file extension onto new_filename before computing/appending the _+MD5-hash suffix, and doesn't reserve space in the length budget for that suffix:

if len(new_filename) > max_filename_length:
    extension_length = len(Path(original_file_path).suffix)
    max_base_filename_length = max_filename_length - extension_length
    truncated_filename = new_filename[:max_base_filename_length]
    hash_suffix = hashlib.md5(new_filename.encode()).hexdigest()
    new_filename = truncated_filename + '_' + hash_suffix + Path(original_file_path).suffix
newFilenameWithExt  = new_filename + Path(original_file_path).suffix

Two bugs:

1. max_base_filename_length only subtracts the extension length, not the _ + 32-char hash that gets appended afterward — so the "truncated" name can still exceed max_filename_length.
2. Since new_filename already ends with the extension after truncation, the next line (newFilenameWithExt = new_filename + suffix) appends the extension a second time, producing a name like ....mp4.mp4 and pushing it well past the OS limit.

Reproduction (from a real log)

OSError: [Errno 63] File name too long: '.../Movie-name-(...)-[...].mp4' -> '.../Movie-name-(...)-[...Gagging_a68f3c2a62cef848afd6bb9ef0ff4fc6.mp4.mp4'

The resulting target filename is 292 characters (vs. the configured 255 limit) and ends in .mp4.mp4.

Additional issue

When the rename/move fails, the code logs a clear one-line error (stash.Error(exitMsg)) but then re-raises the OSError, which propagates to the plugin's top-level catch-all and dumps the full Python traceback to the log as well — burying the clear message under noise.

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Disclosure: this issue and the accompanying fix (PR to follow) were drafted with LLM (Claude) assistance, based on analysis of a real error log; reviewed and submitted by a human maintainer.