Minimize rust ffi crate surface

Minimize Rust FFI Crate Surface

Remove C symbols defined in a Rust FFI crate or file that are either unused or only used in C/C++ unit tests.

Arguments

• <path>: Path to the Rust crate or file.
• <path 1> <path 2>: Multiple Rust crates/files.

If the path doesn't start with src/, assume it to be in the src/redisearch_rs/c_entrypoint directory. E.g. numeric_range_tree_ffi becomes src/redisearch_rs/numeric_range_tree_ffi. If the path points to a directory, review the documentation of all Rust files in that directory.

Instructions

• Use analyze-rust-ffi-crate-surface to enumerate and analyze the usage of all the FFI symbols exposed by the Rust crate or file (e.g. extern "C" fn annotated with #[unsafe(no_mangle)] or type definitions).
• For each unused symbol:
  • Delete its Rust definition.
  • Run C/C++ unit tests to ensure the symbol was indeed unused (via ./build.sh RUN_UNIT_TESTS)
• For each symbol that is only used in C/C++ unit tests, elaborate a plan to either:
  • Refactor the C/C++ unit tests not to use it.
  • Remove the C/C++ unit tests (or assertions) that rely on it, since they are prying into the implementation details of the Rust crate.
  • Keep the symbol, but mark it as "test only" in the Rust documentation.