sgl-project/sglang · error · ValueError

task alias {alias!r} targets undeclared task {target!r}

Error message

task alias {alias!r} targets undeclared task {target!r}

What it means

Every alias in task_aliases must point at a task that is actually declared in this metadata's tasks list. An alias targeting an undeclared task raises this error, because the alias could never resolve at request time.

Source

Thrown at python/sglang/multimodal_gen/runtime/pipelines_core/stages/model_specific_stages/minimax_h3/release_metadata.py:112

            schema_version=1,
            partition=partition,
            tasks=tasks,
            task_aliases=dict(aliases),
            video_sigma_shift=video_sigma,
            audio_sigma_shift=audio_sigma,
        )
        for task in metadata.tasks:
            if canonical_minimax_h3_task(task) != task:
                raise ValueError(
                    f"tasks must contain canonical task names, got {task!r}"
                )
            if partition_for_task(task) != partition:
                raise ValueError(
                    f"task {task!r} does not belong to partition {partition!r}"
                )
        for alias, target in metadata.task_aliases.items():
            if target not in metadata.tasks:
                raise ValueError(
                    f"task alias {alias!r} targets undeclared task {target!r}"
                )
            if canonical_minimax_h3_task(alias) != target:
                raise ValueError(
                    f"unsupported task alias mapping {alias!r} -> {target!r}"
                )
        return metadata

    @property
    def sigma_shift_scales(self) -> dict[str, float]:
        return {"video": self.video_sigma_shift, "audio": self.audio_sigma_shift}

    def canonical_task(self, task: str) -> str:
        normalized = task.strip().lower()
        canonical = self.task_aliases.get(normalized, normalized)
        if canonical not in self.tasks:
            raise ValueError(
                f"task {task!r} is not served by MiniMax H3 partition {self.partition!r}; "

View on GitHub (pinned to 0132848349)

Solutions

1. Either add the target task to tasks (if this partition serves it) or delete the stale alias
2. Keep aliases and tasks in sync by generating both from one source table

Example fix

// before
"tasks": ["image_gen"], "task_aliases": {"t2v": "text_to_video"}
// after
"tasks": ["image_gen", "text_to_video"], "task_aliases": {"t2v": "text_to_video"}

assert all(target in tasks for target in aliases.values()), "alias targets undeclared task"

When it happens

Trigger: task_aliases: {"t2v": "text_to_video"} while tasks only lists "image_gen" — the target is not in the declared set.

Common situations: Trimming the tasks list without pruning aliases, or adding aliases copied from another partition's metadata.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• model_index.json._minimax_h3.task_aliases must map strings t
• unsupported task alias mapping {alias!r} -> {target!r}
• task {task!r} is not served by MiniMax H3 partition {self.pa
• {path} must be a non-empty list
• {path} must contain non-empty strings

AI-assisted analysis of sgl-project/sglang@0132848349 (2026-08-28). Data as JSON: /api/errors/005734df4814e728. Report an issue: GitHub.