Consider switching to `cel-expr-python`

[srikrsna-buf]

Google recently open sourced their cel-python lib based on the C++ implementation. Being a wrapper over C++, it is likely to be more performant than the current native Python implementation.

[stefanvanburen]

Took a peek; currently publishing only linux wheels (not sure how hard it would be to support macOS and windows as a C++ wrapper) and requires python 3.11. Other than that, depending on a pre-v1 package makes me a tad nervous, but the API looks fairly similar to the other CEL libraries.

[stefanvanburen]

Repo: https://github.com/cel-expr/cel-python

[stefanvanburen]

It also doesn't publish a wheel for 3.14 yet.

[stefanvanburen]

Also seemingly does not export type stubs for type-checking, could work around that though. I think all of this is probably fixable upstream, will keep watching their changes.

[stefanvanburen]

Filed cel-expr/cel-python#27 and cel-expr/cel-python#28 about the wheels. I guess I'm less concerned about the types; I'm not familiar enough with these Python C++ wrappers to have a good suggestion about how to provide them. They also have some conformance tests that would need fixing, although it's possible that we could work around those on our end..

[stefanvanburen]

Relatedly, I think this may require us dropping protobuf==5 support (#430).