Implement timestep zero reference images to krea 2 for ostris ref loras.

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• comfy/ldm/krea2/model.py
• comfy/model_base.py

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**/*.py: Keep imports at module scope; avoid inline imports unless they are already part of an established optional-backend probe or are needed to avoid an import cycle.
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• comfy/ldm/krea2/model.py
• comfy/model_base.py

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Files:

• comfy/ldm/krea2/model.py
• comfy/model_base.py

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Files:

• comfy/ldm/krea2/model.py
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Files:

• comfy/ldm/krea2/model.py
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🧠 Learnings (2)

📚 Learning: 2026-02-21T14:01:41.482Z

Learnt from: pythongosssss
Repo: Comfy-Org/ComfyUI PR: 12555
File: comfy_extras/nodes_glsl.py:719-724
Timestamp: 2026-02-21T14:01:41.482Z
Learning: In PyOpenGL, bare Python scalars can be accepted for 1-element array parameters by NumberHandler. This means you can pass an int/float directly to OpenGL texture deletion (e.g., glDeleteTextures(tex)) without wrapping in a list. Verify function-specific expectations and ensure types match what the OpenGL call expects; use explicit lists only when the API requires an array.

Applied to files:

• comfy/ldm/krea2/model.py
• comfy/model_base.py

📚 Learning: 2026-05-13T12:31:45.069Z

Learnt from: rattus128
Repo: Comfy-Org/ComfyUI PR: 13802
File: comfy/pinned_memory.py:19-30
Timestamp: 2026-05-13T12:31:45.069Z
Learning: When reviewing code that uses comfy/pinned_memory.py’s `HostBuffer.extend(size=..., reallocate=...)`: by default (`reallocate` is not True / False), `extend(size=...)` is a *relative increment* that grows the buffer by `size` bytes—so slicing like `[offset:offset+size]` after `hostbuf.extend(size=size)` is correct and the argument should not be rewritten to `offset + size`. Only in the single-segment reallocation mode (`reallocate=True`, e.g., as used by `resize_pin_buffer()` in `comfy/model_management.py`) should `size` be treated as an *absolute target* and the call/arguments should be checked accordingly.

Applied to files:

• comfy/ldm/krea2/model.py
• comfy/model_base.py

🔇 Additional comments (6)

comfy/ldm/krea2/model.py (5)

162-199: LGTM!

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261-267: LGTM!

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268-278: LGTM!

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280-310: LGTM!

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313-351: LGTM!

comfy/model_base.py (1)

2285-2305: LGTM!

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📝 Walkthrough

Walkthrough

This PR adds reference-latent conditioning support to the Krea2 single-stream DiT model. SingleStreamDiT gains a process_img helper and threads ref_latents through forward/_forward, concatenating reference image tokens with primary image tokens and tracking a timestep_zero_index boundary. SingleStreamBlock.forward now splits modulation parameters between base and reference tokens for attention and MLP branches when this index is provided. In comfy/model_base.py, Krea2 was updated to process reference_latents from kwargs, publish them as ref_latents conditioning via CONDList, and compute their expected shapes.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	❓ Inconclusive	No meaningful description was provided, so the PR intent cannot be assessed from the text.	Add a short description of the behavior change and affected components.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title matches the main change: adding timestep-zero reference image support for Krea 2.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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