Batch Version Manager

If you've ever overwritten a good render with a worse one - and then spent an hour not finding the undo - you know the pain this node removes. BatchVersionManagerMEC computes the next free v### directory under a <root>/<show>/<shot>/<task>/ structure and hands you a path you can feed to Save Image. Turn on reserve and it atomically claims the version with a lock file, so two queued prompts (or two machines) can't collide on the same folder.

This is squarely aimed at the VFX/studio workflow, where the pack itself lives: shows, shots, tasks, versions. But it's just as useful for a solo user doing batch sweeps who's tired of manually renaming outputs. Same pack also ships a filesystem-scanning FolderIncrementer family; BatchVersionManager is the stricter, structure-aware sibling.

How it works

The node scans the task directory for existing v### folders, takes the max, and adds one (floored at min_version). With reserve=False it only computes the path - no disk writes at all. With reserve=True it creates the folder and writes a .lock file using exclusive creation, so if another process grabs the same version mid-race, it gets a FileExistsError and advances to the next number and retries, up to max_retries. No lock file, no reservation; that's the whole trick. When you reserve, it also writes a version_manifest.json sidecar (workflow hash, user, host, timestamp, show/shot/task) for a full audit trail - genuinely handy when you need to know exactly which settings produced which pass.

The inputs that matter

• root - absolute output root, e.g. D:/projects/renders.
• show / shot / task - the three levels of the folder tree. Defaults are show / sh010 / comp.
• reserve - the big one. Off = just tell me the next version. On = claim it.
• padding (3) - v001 vs v0001.
• max_retries (5) - how hard to fight for a version under contention.
• min_version (1), forward_slash (true), write_manifest (true) - tweak as needed.

Outputs are the four things you'll wire into Save Image: version_path (full path to the folder), version_int, version_label (v001), and info_json with the reservation metadata.

Installing it

Part of the ComfyUI-CustomNodePacks umbrella pack. ComfyUI Manager → search "CustomNodePacks", or:

cd ComfyUI/custom_nodes
git clone https://github.com/Code2Collapse/ComfyUI-CustomNodePacks.git

Restart ComfyUI. Pure filesystem logic - no models, no extra pip packages. (As always with this pack, don't blanket pip install -r requirements.txt over ComfyUI's own torch/numpy; install only what you're missing.)

Gotchas

The root path is required - the node raises if it's empty, so wire it before your first run. Version-name characters in show/shot/task get sanitized for filesystem safety, which means your pretty names might come back slightly different from what you typed; that's deliberate. And if you see the "max_retries failed" error, it means another process is actively racing you for the same task directory - either raise max_retries or give the task triple a more unique name. Finally, remember that reserve=True creates the folder on the first run of the workflow; on a re-queue you'll get a fresh v###, which is exactly the behavior you want if you use it, and slightly surprising if you expected idempotence.