`instantiation`¶

Calls every node's constructor. Registration proves the module imported; this proves the classes can actually be built.


Needs	`env` (provided by `install`) -- not a server
Default	yes
Fails the run	yes
Source	`orchestration/levels/instantiation.py`

It does not need a running server

LEVEL_REQUIRES gives this level ["env"] only. It spawns its own subprocess from the installed environment, so it can run without registration -- cheaper than the ladder position suggests.

How it works¶

The level generates a script and runs it in a subprocess against the installed environment. The script imports NODE_CLASS_MAPPINGS and calls each constructor in turn, reporting results as JSON. A subprocess is used because a node constructor can crash the interpreter outright -- an access violation should fail one level, not take the run down.

CPU-lane hardening¶

On a non-CUDA runner the script disables CUDA before anything imports ComfyUI, because model_management.py calls torch.cuda at import time:

os.environ["CUDA_VISIBLE_DEVICES"] = ""
torch.cuda.is_available = lambda: False
torch.cuda.device_count = lambda: 0
torch.cuda.current_device = lambda: 0

CUDA_VISIBLE_DEVICES="" alone is not enough on Windows, where torch's C++ CUDA calls can still fault with an access violation when no driver is present -- hence the monkeypatch. Declared CUDA packages are mocked by the same probe-based rule install uses.

What it catches¶

Constructor work that assumes something the machine does not have:

a GPU (self.device = torch.device("cuda") in __init__)
a model file on disk at import or construction time
network access to fetch weights or config
a writable path that does not exist on a fresh install

These are invisible to registration, which only proves the module imported. A class can register fine and fail the moment ComfyUI builds it.

What it does not catch¶

Only __init__ runs. Nothing calls the node's FUNCTION, so anything that happens during execution -- shape errors, dtype mismatches, actual inference -- belongs to execution. It also constructs with no arguments, so it cannot catch failures that depend on particular input values.

Failure output¶

Failures are collected rather than raised on the first one: the level reports how many nodes failed and lists them, so one broken constructor does not hide the other four.

Config¶

No keys of its own. In the default set; needs env, so listing it pulls in install.

instantiation¶