[Python11235]

Summary

Python binding fixes in python/cactus/bindings/cactus.py:

• Grow buffers instead of failing. cactus_tokenize, cactus_embed, cactus_image_embed, cactus_audio_embed and cactus_preprocess_audio_features now retry with a larger buffer when the C side returns -2 (buffer too small). Before, they raised a generic error. -2 means "buffer too small" in all five C implementations.
• Clear error for missing optional ops. Optional graph ops that are missing from the loaded library now raise RuntimeError("... rebuild with cactus build --python") instead of a bare AttributeError. The gather → cactus_graph_gather fallback still works.
• Index helpers. Empty ids and empty embeddings are handled, and embedding sizes returned by cactus_index_get are bounds-checked.
• Graph.input checks that dynamic_dims has the same length as shape.
• Less FFI work. Tensor shape and dtype are resolved lazily, graph inputs reuse the shape and dtype they were created with, and set_input skips the copy when the array already has the target dtype and layout.
• PCM marshaling uses one buffer copy instead of unpacking every byte into a ctypes array.

Replaces #814, which failed the DCO check. This is the same change, squashed and signed off.

Testing

• pytest tests/ --ignore=tests/test_model.py --ignore=tests/test_server_live.py gives the same results as main (171 passed, no new failures). I ran it against a stub library on x86, because the kernels need ARM to build.
• A targeted script for the retry paths, the optional-op errors, the gather fallback, the concurrent cactus_complete calls and PCM marshaling: all pass.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Hf1fEfGn1rnodpQdjope6c