DiffusionGemma: set UNSLOTH_IS_PRESENT so the shim runs on a clean install#6259
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A clean install could not run DiffusionGemma: the runner spawns python -m unsloth_zoo.diffusion_studio.shim, and unsloth_zoo refuses to import unless UNSLOTH_IS_PRESENT is set (normally by import unsloth). The shim never imports unsloth, so the subprocess died with 'Please install Unsloth via pip install unsloth!' and the model load failed with a 500. Set the flag in the runner child env, as unsloth does on import.
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This pull request modifies _start_diffusion_server in studio/backend/core/inference/llama_cpp.py to set the UNSLOTH_IS_PRESENT environment variable to "1", preventing loading issues with unsloth_zoo when imported by the shim. There are no review comments on this pull request, and I have no feedback to provide.
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danielhanchen
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The studio backend lazily imports unsloth_zoo submodules (export's llama_cpp, hardware's vllm_utils, mlx, chat_templates). Each imports the top-level unsloth_zoo, which raises 'Please install Unsloth via pip install unsloth' unless UNSLOTH_IS_PRESENT is set (normally by import unsloth). Only hardware.py set it per-site; the rest crash on a clean install, and it surfaced on Windows. Set it once at backend startup (as unsloth does on import) so every site, and the DiffusionGemma runner, works across platforms. Follow-up to #6259 (which covered only the shim subprocess env).
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Summary
A clean install cannot run DiffusionGemma. The runner spawns
python -m unsloth_zoo.diffusion_studio.shim, andunsloth_zoo/__init__.pyrefuses to import unlessUNSLOTH_IS_PRESENTis in the environment (normally set byimport unsloth). The shim never importsunsloth, so on a fresh PyPI/install.sh setup the subprocess dies with:and the model load returns a 500 (
DiffusionGemma runner failed to become healthy). It only appeared to work in dev because an already-exportedUNSLOTH_IS_PRESENTwas inherited from the shell.Fix
Set
UNSLOTH_IS_PRESENT=1in the runner child environment, exactly asunslothdoes on import. Follow-up to #6255 (the flag belongs with the runner launch but landed after that PR merged).Verification
Launched Studio with
UNSLOTH_IS_PRESENTstripped from the parent env (the clean-install condition): loadingunsloth/diffusiongemma-26B-A4B-it-GGUFnow returns 200, the shim child hasUNSLOTH_IS_PRESENT=1, the visual-server reaches READY, and a streaming request producesdiffusion_frameevents. Previously this was a 500 with the ImportError.