Support parsing complex queries with deeply nested ASTs

[seanlinsley]

This matches the same behavior in the Ruby gem: pganalyze/pg_query#238

Upstream changes were needed in the prost crate that haven't been merged yet: tokio-rs/prost#785

Without further changes, the test suite would run into a stack overflow. There are some ways around this:

• Create a thread with a larger stack size. This is what the PR currently does b/c it didn't require adding a dependency. But its performance is limited by it creating a new thread for every call. There is also safety concerns with passing unsafe data structures to a different thread.
• Use the heap to dynamically grow the stack size https://crates.io/crates/stacker. This is a fairly popular crate, but I'm wary of the maybe_grow performance. If someone hasn't put together benchmarks we may want to use grow instead.
• https://crates.io/crates/decurse
• https://crates.io/crates/tailcall

[seanlinsley]

Since any solution to the stack overflow issue would involve pulling in dependencies that most users won't need, I decided to document this issue in the README so downstream applications can increase the stack size as needed for their application.

[lfittl]

👍 FWIW, this looks good to me - depending on when the upstream change to prost lands it might be nice to hold off until that's actually merged, but apart from that it looks good to ship.

[seanlinsley]

@lfittl thoughts on best way to install the protobuf compiler on Windows, for CI?

[lfittl]

@lfittl thoughts on best way to install the protobuf compiler on Windows, for CI?

Probably install the binary provided on the releases page: https://github.com/protocolbuffers/protobuf/releases/tag/v29.0 (not sure if there is an alias for a current version, but I guess we could pin it)

To help me understand the change better, is there a reason we need to add this here, vs didn't need it on main?

[seanlinsley]

This PR is built on top of a more recent version of the prost crate, which now relies that your system have the protobuf compiler installed separately.

[lfittl]

This PR is built on top of a more recent version of the prost crate, which now relies that your system have the protobuf compiler installed separately.

Makes sense!

I think maybe you can use this GH action to install the compiler in a OS-agnostic way: https://github.com/marketplace/actions/setup-protoc (we already have this forked to https://github.com/pganalyze/setup-protoc for security reasons, so you can probably just go ahead and use that fork?)