- Step cache 'Off' is preserved: the frontend defaulted to 'off' and mapped it
to an omitted transformer_cache, which the backend now reads as 'auto', so
leaving the control at Off silently enabled FBCache on 20+ step families.
Default the control to Auto, add an explicit Auto option, and send
auto -> omitted so Off maps to an explicit cache-off.
- Kernel auto-install adds --no-deps: 'pip install --only-binary :all: xformers'
resolves xformers' pinned torch and replaces the running torch/triton. --no-deps
installs only the best-effort kernel wheel; an ABI mismatch just fails to import
and falls back to native, never clobbering core deps.
- Do not retry a failed kernel install under the load lock: the pre-install runs
outside the locks, then the in-lock resolve re-attempts pip (up to 600s) while
holding _generate_lock/_lock and blocking unload/cancel/new loads. Record the
attempt in a process-level set so the in-lock call short-circuits to native.
- Cache auto-toggle keys on effective denoise steps: an image-conditioned run with
strength < 1 (upscale default 0.35) denoises a fraction of the requested steps,
so a 28-step request runs ~10 steps. Compute the effective count the way diffusers
get_timesteps does and gate FBCache on it, only when strength is actually applied.
A successful on-demand wheel install writes into site-packages after the
import system already cached that directory's listing, so the very next
find_spec / import in the same process can miss the freshly installed
package when the install lands within the directory mtime's resolution.
That silently falls set_attention_backend back to native on first use.
Call importlib.invalidate_caches() after a successful install so the
kernel is picked up immediately, and cover both the success and failure
paths in the attention installer tests.
Review follow-ups on the image-generation PR:
- ControlNet: resolve_controlnet accepts a bare owner/name repo without the
non-GGUF base trust gate, and _controlnet_pipe hands it straight to
from_pretrained. A malicious pickle .bin would deserialize on load, so run
the same Hugging Face malware preflight (evaluate_file_security) the chat and
export loaders use before any remote ControlNet load; local dirs are exempt.
- Dataset thumbnails: key the cache on the full filename instead of the stem so
sample.png and sample.jpg no longer collide on one .thumbs file (which could
serve or delete the wrong image); the delete cleanup globs the same key.
- Diffusion training start: mirror start_training's API-key guard so an API
client cannot start training (which frees VRAM by unloading chat) while an
inference request is streaming; it now returns 409 before any GPU is freed.
- Model picker: include the curated safetensors row keys in the recommended
roving key list so arrow-key navigation reaches those rows instead of hitting
the duplicate option-missing id.
Tests: ControlNet malware gate (remote blocked before from_pretrained, local
skipped), thumbnail same-stem cache separation, API-key diffusion-start 409
before GPU free. Full diffusion suites green.
