[Model] Add HSDP support for LTX-2 (#2899)

Signed-off-by: hanzheli <hanzheli@kuaishou.com>
Signed-off-by: fywc <hanzheli@kuaishou.com>

tests/diffusion/models/ltx2/test_ltx2_hsdp.py

@@ -0,0 +1,25 @@
+import pytest
+import torch.nn as nn
+
+from vllm_omni.diffusion.models.ltx2.ltx2_transformer import LTX2VideoTransformer3DModel
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+
+def test_ltx2_exposes_hsdp_shard_conditions_for_transformer_blocks():
+    model = object.__new__(LTX2VideoTransformer3DModel)
+    nn.Module.__init__(model)
+    model.transformer_blocks = nn.ModuleList([nn.Linear(4, 4) for _ in range(2)])
+    model.norm_out = nn.LayerNorm(4)
+
+    conditions = getattr(model, "_hsdp_shard_conditions", None)
+
+    assert conditions is not None
+    assert len(conditions) == 1
+
+    matched = []
+    for name, module in model.named_modules():
+        if any(cond(name, module) for cond in conditions):
+            matched.append(name)
+
+    assert matched == ["transformer_blocks.0", "transformer_blocks.1"]