SeedVR2 native: drop disk-load prompt embeddings, restore checkpoint buffer access

[pollockjj]

Summary

PR #51 (merged into issue_101) introduced _load_seedvr2_prompt_embed[s] and _SEEDVR2_PROMPT_EMBED_CANDIDATES in comfy_extras/nodes_seedvr.py, making SeedVR2Conditioning.execute load pos_emb.pt / neg_emb.pt from one of four search paths via folder_paths.get_full_path:

embeddings:SEEDVR2/{pos,neg}_emb.pt
embeddings:{pos,neg}_emb.pt
custom_nodes:ComfyUI-SeedVR2-Canonical/vendor/SeedVR/{pos,neg}_emb.pt
custom_nodes:ComfyUI-SeedVR2_VideoUpscaler/{pos,neg}_emb.pt

The native SeedVR2 pipeline was silently dependent on third-party custom_nodes being present on disk. Disabling the numz pack made SeedVR2Conditioning raise FileNotFoundError.

This PR removes that dependency by restoring Yusef's upstream pattern: read model.positive_conditioning and model.negative_conditioning directly off the diffusion model.

Why this works

The official seedvr2_3b_fp16vae.safetensors checkpoint bundles both prompt embeddings as model-level buffers:

$ safetensors keys for seedvr2_3b_fp16vae.safetensors
  model.positive_conditioning: shape=(58, 5120) dtype=torch.bfloat16
  model.negative_conditioning: shape=(64, 5120) dtype=torch.bfloat16

comfy/ldm/seedvr/model.py already registers both buffers in the diffusion model via register_buffer. The state-dict load populates them. Yusef's upstream PR (Comfy-Org#11294) reads them directly off model — no filesystem lookup, no custom-node dependency.

Changes

comfy_extras/nodes_seedvr.py

• Remove import folder_paths.
• Remove _SEEDVR2_PROMPT_EMBED_CANDIDATES.
• Remove _load_seedvr2_prompt_embed and _load_seedvr2_prompt_embeds.
• SeedVR2Conditioning.execute reads pos_cond = model.positive_conditioning and neg_cond = model.negative_conditioning.

The disable_model_cfg1_optimization() call (also added by PR #51) is preserved — that part of PR #51 is correct (the SeedVR2 DiT requires the [neg, pos] chunk concat that Comfy's CFG=1 short-circuit otherwise strips).

tests-unit/comfy_extras_test/test_seedvr_conditioning_hardening.py

• Drop the four _load_seedvr2_prompt_embed* unit tests (lines 337-528).
• test_seedvr2_conditioning_disables_cfg1_optimization no longer monkey-patches _load_seedvr2_prompt_embeds — the existing _DiffusionModel test fixture already registers the conditioning buffers via register_buffer, which is exactly the contract SeedVR2Conditioning.execute consumes post-revert.

tests-unit/comfy_extras_test/test_seedvr_input_processing_temporal_overlap.py + test_seedvr_temporal_overlap.py

• Add parameters() to _FakeFirstStage to satisfy tiled_vae's next(vae_model.parameters()).dtype call (introduced by PR SeedVR2 native encode + conditioning (companion to PR #50) #51's encode dispatch refactor).
• Patch nodes_seedvr.tiled_vae to capture encode kwargs; the dispatch site moved off vae.encode_tiled in PR SeedVR2 native encode + conditioning (companion to PR #50) #51, so the old mock no longer fires.

Net diff

4 files changed, 20 insertions(+), 256 deletions(-)

Verification

• ruff check clean on all four files.
• 94 tests passed, 0 failed across the seedvr2 test surface (18 test files exercising comfy/ldm/seedvr/, comfy_extras/nodes_seedvr.py, related VAE wrappers, RoPE delegation, and conditioning hardening).

Test plan

• Disk-load helpers (_load_seedvr2_prompt_embed, _load_seedvr2_prompt_embeds, _SEEDVR2_PROMPT_EMBED_CANDIDATES, import folder_paths) absent from comfy_extras/nodes_seedvr.py post-merge.
• SeedVR2Conditioning.execute reads buffers directly from the resolved diffusion model.
• test_seedvr2_conditioning_disables_cfg1_optimization passes without the _load_seedvr2_prompt_embeds monkeypatch.
• Native SeedVR2 inference does not require any custom_node pack on disk.

Linked

• Tracking: pollockjj/mydevelopment#224 (also tracks the rope-rewrite memory regression in SeedVR2 native RoPE: rewire NaMMRotaryEmbedding3d.forward to apply_rope1 directly (closes pollockjj/mydevelopment#224) #52).
• Parent: pollockjj/mydevelopment#101 (SeedVR2 native trunk).
• Upstream PR: feat: Add support For SeedVR2 (CORE-6) Comfy-Org/ComfyUI#11294.
• Introducing PR: SeedVR2 native encode + conditioning (companion to PR #50) #51 (this PR removes the filesystem dependency it added).

[Copilot]

Pull request overview

Removes SeedVR2’s on-disk prompt-embedding lookup from SeedVR2Conditioning and restores the native behavior of reading positive/negative conditioning directly from buffers registered on the diffusion model, eliminating an implicit dependency on third-party custom_nodes packs.

Changes:

• Drop folder_paths-based prompt-embedding search and disk loading helpers in comfy_extras/nodes_seedvr.py.
• Update SeedVR2Conditioning.execute to use model.positive_conditioning / model.negative_conditioning buffers.
• Adjust SeedVR2 temporal-overlap tests to reflect the tiled_vae(..., encode=True) encode dispatch and add minimal stubs needed by the refactor.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
comfy_extras/nodes_seedvr.py	Removes filesystem dependency for prompt embeddings; uses model buffers for SeedVR2 conditioning.
tests-unit/comfy_extras_test/test_seedvr_conditioning_hardening.py	Removes tests for deleted disk-load helpers; keeps CFG=1 optimization-disable test aligned with buffer-based conditioning.
tests-unit/comfy_extras_test/test_seedvr_temporal_overlap.py	Updates mocks to intercept tiled_vae encode dispatch; adds parameters() stub for VAE wrapper behavior.
tests-unit/comfy_extras_test/test_seedvr_input_processing_temporal_overlap.py	Same as above for the parallel temporal-overlap wiring test.

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[pollockjj]

Closing per direction: PR scope creep. Will resubmit with only the disk-load reversion (nodes_seedvr.py + test_seedvr_conditioning_hardening.py deletions). The temporal_overlap test edits in this PR don't belong in a reversion.