pipeline.model is a tagged union: a mapping with exactly one key, which
names the model family (ltx2, minimax_h3, longcat, or generic) and selects
that family's options class. The former sibling sections pipeline.ltx2,
pipeline.minimax_h3, and pipeline.longcat, and the DiT/VAE architecture
override dicts pipeline.dit and pipeline.vae, live inside the family block.
The parser implements tagged unions as a general mechanism (a dataclass
with a TAGS table); the family is readable as pipeline.model.family.
Resolution validates the tag against the family that the registry chose
for model_path (validate_model_family raises and names the registry class
and the right block) and fills the family's empty block when the input has
none (fill_model_family), so readers never see None. Family-only fills and
derivations (the MiniMax-H3 parallel-VAE environment variables, the LTX-2
tile-size derivation and refine preset copy, the LongCat BSA mirrors) run
only for their family.
Against the 3f6893a0 goldens every PipelineConfig is identical and no
other field differs beyond the allowed categories; family-only settings
are no longer decided on models of another family. LingBot-Video reads
its refiner switch from pipeline.preset_overrides.refine.enabled and loads
the refiner by default when the checkpoint has one, as at 3f6893a0.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CbSuTKA9oX4YsECdcBPAsX
- The component loaders read engine.offload.*, engine.precision.*,
engine.parallelism.hsdp_*, engine.use_fsdp_inference, engine.compile.*,
engine.attention.*, pipeline.components.*, and pipeline.flow_shift (the
scheduler shift) from the resolved config, and compile settings through
torch_compile_kwargs(). They no longer write model_paths (the pipeline's
ComponentState records paths) or apply the unified-memory policy to the
config; the text-encoder loader only queries the policy for its target
device.
- PipelineComponentLoader.load_module and TransformerLoader.load take
loading_teacher_critic_model instead of reading an attribute that
training code set on the config.
- Loader, encoder, transformer, VAE, and device-policy tests build resolved
configs; the env-var docs name typed paths.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012M91wnVFmPEvJ9h39r5BH7
An unsupported FASTVIDEO_ATTENTION_BACKEND name, such as a typo, was ignored
and the run fell back to automatic backend selection without telling the
user. An explicit attention_backend argument with the same name raised.
get_env_variable_attn_backend now raises ValueError for an unsupported name,
using the same parse as an explicit request (coerce_attn_backend). Every
reader goes through it: the fill_attention_backend_from_env resolution
step, FastVideoArgs.__post_init__, and the attention selector's
environment fallbacks.
The golden case environment/attention_backend_unknown_name now records the
error, and the registry description and env_vars.md table say that an
unsupported name raises.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012M91wnVFmPEvJ9h39r5BH7
