Many shared workflows save their loaders blank so people load their own
picture. Pressing Run first started the run, and core Load Image failed
inside it with "[Errno 21] Is a directory". Now the run stops before it
is sent: one message, "Load a picture first:" and the node's name, and
the loader gets a red outline (on the classic canvas and in Nodes 2.0).
It covers core Load Image, Load Image (as Mask), Load Image (from
Outputs) and Load Video, and the pack's Load Image + Pad, Image Crop +
Rotate + Pad, Load Video and both Video Crop + Rotate + Pad nodes (the
file or the local path, whichever the mode reads). It looks at the
prompt the frontend is about to send and walks it the way ComfyUI does,
so bypassed and muted loaders, loaders fed by a link, loaders no output
needs, loaders behind a lazy input and outputs left out of "Queue
selected output nodes" never stop a run. Prompts sent straight to the
API are not checked.
The frontend has no extension hook that can stop a queue, so
app.queuePrompt is wrapped; it only reads, and builds the prompt a
second time only when a blank loader is on the canvas. Anything
unexpected lets the run through unchanged.
When ComfyUI does reject a prompt, a check that reads several inputs
comes back once per input. api.queuePrompt's answer is tidied so each
AusBoss node shows one entry per message, on the input the message is
about. Other packs' nodes are left as ComfyUI sends them.
ausboss
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