Sam2 add defaut task config.

[chinazhangchao]

No description provided.

[DingmaomaoBJTU]

Design feedback: MODEL_TASK_DEFAULTS introduces a second parallel registry

sam.py now expresses the same fact — "sam2's canonical export task is mask-generation" — in two places:

# 1. MODEL_TASK_DEFAULTS
MODEL_TASK_DEFAULTS = {"sam2": "mask-generation"}

# 2. MODEL_CLASS_MAPPING (already implies this via its primary entry)
MODEL_CLASS_MAPPING = {
    ("sam2", "mask-generation"): SAM2MaskGeneration,  # same information
    ("sam2", "feature-extraction"): Sam2VisionEncoder,
}

The value of MODEL_TASK_DEFAULTS["sam2"] and the key of MODEL_CLASS_MAPPING's primary entry are the same string. Adding a new model now requires keeping two tables in sync, with no enforcement — it's easy to define MODEL_TASK_DEFAULTS["newmodel"] = "task-a" while forgetting to add ("newmodel", "task-a") to MODEL_CLASS_MAPPING, causing a silent wrong-class fallback.

Alternative: encode the default task as a None-sentinel entry in MODEL_CLASS_MAPPING

# sam.py — one table instead of two
MODEL_CLASS_MAPPING = {
    ("sam2", None): "mask-generation",         # None = default task for auto-detection
    ("sam2", "mask-generation"): SAM2MaskGeneration,
    ("sam2", "feature-extraction"): Sam2VisionEncoder,
    ...
}

_get_custom_model_class reads the sentinel before the class lookup:

def _get_custom_model_class(model_type: str, task: str) -> tuple[str, type | None]:
    default_task = MODEL_CLASS_MAPPING.get((model_type_normalized, None))
    resolved_task = default_task or task
    return resolved_task, MODEL_CLASS_MAPPING.get((model_type_normalized, resolved_task))

Benefits:

• Single table; the sentinel entry structurally enforces that a matching class entry must exist
• task.py no longer imports MODEL_TASK_DEFAULTS — all model-specific data flows through the existing MODEL_CLASS_MAPPING path
• Adding a new model still only requires editing hf/newmodel.py

The only cost is that MODEL_CLASS_MAPPING's value type becomes str | type (sentinel entries hold a task string, others hold a class). Worth considering as a follow-up if this pattern is going to extend to other model families.

🤖 Generated with Claude Code