unsloth/studio/backend/tests/test_diffusion_attention_trim.py
Daniel Han 6e2e8c846c Harden video diffusion cache, CFG-parallel replica, and layerwise-fp8 rollback
- diffusion_attention: clear the HunyuanVideo-1.5 null-mask flag with an always_call
  post-hook so it is scoped to one hooked forward and never latches across an
  exception; add attention_backend_supported_on_device to arch-gate an
  already-resolved backend on a specific (heterogeneous) CUDA device.
- video: make the explicit MagCache resize transactional via _step_cache_all_or_none
  (refuse to stack a fresh cache over one that could not be disabled; roll a mixed
  resize back and report the true state); raise on a failed all-or-none rollback
  instead of falsely reporting an uncached pipeline.
- diffusion_cfg_parallel: re-validate the attention backend on the replica device
  and pin native there when unsupported; mirror the primary's max tier on the
  replica (max-autotune compile + direct QKV fusion) via a new speed_mode arg;
  prefer a viable heterogeneous secondary GPU over an unusable identical one; clear
  the const cache at each plan_generation.
- diffusion_vae_quant / diffusion_precision: detect a partial diffusers
  layerwise-fp8 mutation (leftover casting hooks the torchao detector cannot see)
  and fail the load closed, while a clean failure still falls back to dense.
- video_speedmem_bench: engage the dual-expert cache all-or-none like the loader.
- frontend video api: add text_encoder_quant / vae_quant and the auto/off literals
  to VideoLoadRequest so typed callers match the backend contract.
2026-07-13 01:30:22 +00:00

252 lines
12 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""Tests for the HunyuanVideo-1.5 padded-text attention trim.
``_trim_stream`` / ``_hunyuan_trim_pre_hook`` / ``install_hunyuan_attention_trim`` use real torch
tensor ops, so unlike the attention-backend policy tests in ``test_diffusion_attention.py`` these
require torch. Kept in a separate module so that file stays collectable without torch installed.
"""
from __future__ import annotations
import types
import pytest
# Skip at collection (not abort) when torch is absent so the rest of the backend suite
# stays collectable, matching how the policy tests next door gate their heavy imports.
torch = pytest.importorskip("torch")
import core.inference.diffusion_attention as att # noqa: E402
def test_trim_stream_drops_trailing_padding():
# right-padded (valid prefix): drop the globally-invalid tail, keep valid, flag all_valid.
states = torch.arange(6.0).reshape(1, 6, 1)
mask = torch.tensor([[1, 1, 1, 0, 0, 0]])
out_s, out_m, all_valid = att._trim_stream(states, mask)
assert out_s.shape == (1, 3, 1)
assert torch.equal(out_s[0, :, 0], torch.tensor([0.0, 1.0, 2.0]))
assert out_m.shape == (1, 3) and all_valid is True
def test_trim_stream_layout_agnostic_drops_only_global_padding():
# left-padded (valid suffix): any(dim=0) keeps positions valid for at least one element,
# so the leading globally-invalid columns are dropped regardless of padding side.
states = torch.arange(4.0).reshape(1, 4, 1)
mask = torch.tensor([[0, 0, 1, 1]])
out_s, out_m, all_valid = att._trim_stream(states, mask)
assert torch.equal(out_s[0, :, 0], torch.tensor([2.0, 3.0])) and all_valid is True
def test_trim_stream_full_mask_is_noop():
states = torch.ones(1, 4, 2)
mask = torch.ones(1, 4, dtype = torch.long)
out_s, out_m, all_valid = att._trim_stream(states, mask)
assert out_s.shape == (1, 4, 2) and all_valid is True
def test_trim_stream_none_mask_passthrough():
states = torch.ones(1, 4, 2)
out_s, out_m, all_valid = att._trim_stream(states, None)
assert out_s is states and out_m is None and all_valid is True
def test_trim_stream_mixed_batch_not_all_valid():
# batch>1 with different valid sets: the union is kept, but a column valid for only one
# element remains partially padded -> all_valid False -> caller keeps the dense mask.
states = torch.ones(2, 4, 1)
mask = torch.tensor([[1, 1, 0, 0], [1, 1, 1, 0]]) # elem1 has 2 valid, elem2 has 3
out_s, out_m, all_valid = att._trim_stream(states, mask)
assert out_s.shape == (2, 3, 1) # dropped the last col (invalid for both)
assert all_valid is False
def _fake_dit(n_blocks = 2):
blocks = [types.SimpleNamespace(attn = types.SimpleNamespace()) for _ in range(n_blocks)]
return types.SimpleNamespace(transformer_blocks = blocks)
def test_trim_pre_hook_empties_t2v_image_and_trims_and_flags():
dit = _fake_dit()
kwargs = {
"image_embeds": torch.zeros(1, 5, 3), # all-zero -> t2v -> emptied
"encoder_hidden_states": torch.arange(4.0).reshape(1, 4, 1),
"encoder_attention_mask": torch.tensor([[1, 1, 0, 0]]),
"encoder_hidden_states_2": torch.arange(3.0).reshape(1, 3, 1),
"encoder_attention_mask_2": torch.tensor([[1, 0, 0]]),
}
args, out = att._hunyuan_trim_pre_hook(dit, (), kwargs)
assert out["image_embeds"].shape == (1, 0, 3) # image tokens dropped
assert out["encoder_hidden_states"].shape == (1, 2, 1) # mllm trimmed to 2 valid
assert out["encoder_hidden_states_2"].shape == (1, 1, 1) # byt5 trimmed to 1 valid
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is True for b in dit.transformer_blocks)
def test_trim_stream_all_invalid_yields_empty_but_valid():
# A fully-padded secondary stream (e.g. unused byt5 in t2v) trims to 0 length and reports
# all_valid True (vacuous) so it does NOT drop the fast path -- it just contributes no tokens.
states = torch.ones(1, 5, 2)
mask = torch.zeros(1, 5, dtype = torch.long)
out_s, out_m, all_valid = att._trim_stream(states, mask)
assert out_s.shape == (1, 0, 2) and all_valid is True
def test_trim_pre_hook_byt5_all_invalid_keeps_fast_path():
# The real t2v case: byt5 is entirely padding (valid=0). It must be emptied WITHOUT dropping
# the null-mask fast path, since mllm still carries the prompt.
dit = _fake_dit()
kwargs = {
"image_embeds": torch.zeros(1, 5, 3),
"encoder_hidden_states": torch.arange(4.0).reshape(1, 4, 1),
"encoder_attention_mask": torch.tensor([[1, 1, 1, 0]]),
"encoder_hidden_states_2": torch.ones(1, 6, 1),
"encoder_attention_mask_2": torch.zeros(1, 6, dtype = torch.long), # all padding
}
_, out = att._hunyuan_trim_pre_hook(dit, (), kwargs)
assert out["encoder_hidden_states"].shape == (1, 3, 1)
assert out["encoder_hidden_states_2"].shape == (1, 0, 1) # byt5 emptied
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is True for b in dit.transformer_blocks)
def test_trim_pre_hook_empty_primary_reverts_and_disables():
# Pathological empty prompt: mllm has 0 valid tokens. The TokenRefiner must not get a
# 0-length sequence -> revert all inputs to original and take the stock dense-mask path.
dit = _fake_dit()
mllm = torch.ones(1, 4, 1)
kwargs = {
"image_embeds": torch.zeros(1, 5, 3),
"encoder_hidden_states": mllm,
"encoder_attention_mask": torch.zeros(1, 4, dtype = torch.long), # 0 valid
}
_, out = att._hunyuan_trim_pre_hook(dit, (), kwargs)
assert out["encoder_hidden_states"] is mllm # reverted (not emptied)
assert out["image_embeds"].shape == (1, 5, 3) # image revert too
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)
def test_trim_pre_hook_keeps_i2v_image():
dit = _fake_dit()
img = torch.ones(1, 5, 3) # nonzero -> i2v -> kept
kwargs = {
"image_embeds": img,
"encoder_hidden_states": torch.arange(4.0).reshape(1, 4, 1),
"encoder_attention_mask": torch.tensor([[1, 1, 1, 1]]),
}
_, out = att._hunyuan_trim_pre_hook(dit, (), kwargs)
assert out["image_embeds"] is img # not emptied
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is True for b in dit.transformer_blocks)
def test_trim_pre_hook_mixed_batch_flags_false():
dit = _fake_dit()
kwargs = {
"image_embeds": torch.zeros(2, 2, 3),
"encoder_hidden_states": torch.ones(2, 4, 1),
"encoder_attention_mask": torch.tensor([[1, 1, 0, 0], [1, 1, 1, 0]]),
}
_, out = att._hunyuan_trim_pre_hook(dit, (), kwargs)
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)
def test_trim_pre_hook_never_raises_sets_flag_false():
# A malformed mask (not a tensor) must not break the forward: flag False, no exception.
dit = _fake_dit()
kwargs = {"encoder_hidden_states": torch.ones(1, 2, 1), "encoder_attention_mask": "oops"}
args, out = att._hunyuan_trim_pre_hook(dit, (), kwargs)
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)
def test_trim_pre_hook_restores_inputs_on_midtrim_failure():
# A later stream trips the trim AFTER earlier inputs were mutated. The fallback must restore
# the ORIGINAL kwargs so the stock dense-mask path runs on them, never a half-trimmed mix.
dit = _fake_dit()
img = torch.zeros(1, 5, 3)
mllm = torch.arange(4.0).reshape(1, 4, 1)
mllm_mask = torch.tensor([[1, 1, 0, 0]])
byt5 = torch.ones(1, 3, 1)
kwargs = {
"image_embeds": img,
"encoder_hidden_states": mllm,
"encoder_attention_mask": mllm_mask,
"encoder_hidden_states_2": byt5,
"encoder_attention_mask_2": "oops", # malformed -> _trim_stream raises after mllm is trimmed
}
_, out = att._hunyuan_trim_pre_hook(dit, (), kwargs)
assert out["image_embeds"] is img # emptied then restored
assert out["encoder_hidden_states"] is mllm # trimmed then restored
assert out["encoder_attention_mask"] is mllm_mask
assert out["encoder_hidden_states_2"] is byt5
assert out["encoder_attention_mask_2"] == "oops"
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)
def test_trim_pre_hook_absent_stream_not_written_back():
# If encoder_hidden_states is absent (passed positionally), the hook must NOT write it back
# (would collide) and must drop the fast path rather than null a mask it never verified.
dit = _fake_dit()
kwargs = {"image_embeds": torch.zeros(1, 4, 3)} # no encoder_hidden_states key
_, out = att._hunyuan_trim_pre_hook(dit, (torch.ones(1, 5, 1),), kwargs)
assert "encoder_hidden_states" not in out
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)
def test_install_trim_noop_for_non_hunyuan_family():
fam = types.SimpleNamespace(transformer_class = "WanTransformer3DModel")
pipe = types.SimpleNamespace(transformer = types.SimpleNamespace())
assert att.install_hunyuan_attention_trim(pipe, fam) is False
def test_install_trim_noop_when_transformer_class_mismatch():
# Family claims Hunyuan but the loaded module isn't -> no processors touched, no diffusers
# import; returns False rather than swapping an unknown attention processor.
fam = types.SimpleNamespace(transformer_class = "HunyuanVideo15Transformer3DModel")
pipe = types.SimpleNamespace(transformer = types.SimpleNamespace()) # class name mismatch
assert att.install_hunyuan_attention_trim(pipe, fam) is False
# ── null-mask flag lifecycle (scoped to one hooked forward) ───────────────────────
def test_set_and_post_hook_clear_null_mask_flag():
# _set_hunyuan_null_mask flips every block's flag; the post-hook clears it and returns
# the output unchanged.
dit = _fake_dit()
att._set_hunyuan_null_mask(dit, True)
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is True for b in dit.transformer_blocks)
sentinel = object()
returned = att._hunyuan_trim_post_hook(dit, (), sentinel)
assert returned is sentinel
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)
def test_post_hook_always_clears_flag_after_forward_and_on_exception():
# Wire the pre+post hooks the way install_hunyuan_attention_trim does on a real module: the
# flag is only ever True DURING the forward its pre-hook set up. After the call it is False,
# so a later direct dit.forward(...) can never run unmasked over untrimmed padding -- and the
# always_call post-hook clears it even when the forward raises (no latch across exceptions).
class _DiT(torch.nn.Module):
def __init__(self):
super().__init__()
self.transformer_blocks = [
types.SimpleNamespace(attn = types.SimpleNamespace()) for _ in range(2)
]
self.boom = False
def forward(self):
# The processor would read a True flag here (padding removed by the pre-hook).
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) for b in self.transformer_blocks)
if self.boom:
raise RuntimeError("mid-forward boom")
return "ok"
dit = _DiT()
dit.register_forward_pre_hook(lambda m, _a: att._set_hunyuan_null_mask(m, True))
dit.register_forward_hook(att._hunyuan_trim_post_hook, always_call = True)
assert dit() == "ok"
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)
dit.boom = True
with pytest.raises(RuntimeError):
dit()
assert all(getattr(b.attn, att._NULL_ATTN_FLAG) is False for b in dit.transformer_blocks)