refactor(expr): better error handling and reporting for expressions

[BugenZhao]

Signed-off-by: Bugen Zhao i@bugenzhao.comI hereby agree to the terms of the RisingWave Labs, Inc. Contributor License Agreement.

What's changed and what's your intention?

See #11443 for the background.

Attempt to use snafu to refactor error types for expression crate.

risingwave/src/expr/src/error.rs

Lines 90 to 95 in 1e3c551

	#[snafu(display("failed to call udf `{ident}`"))]
	Udf {
	#[snafu(source(from(risingwave_udf::Error, Box::new)))]
	source: Box<risingwave_udf::Error>,
	ident: Box<str>,
	},

Benefits compared to thiserror:

• Directly from the inner type (risingwave_udf::Error) of the boxed error.
• Follow the convention of source and provide more strictly.
• Structs like UdfSnafu allow us to construct errors more easily by avoiding repeating the source error and performing implicit cast (&str -> Box<str>), which encourages developers to provide more context.

risingwave/src/expr/src/expr/expr_udf.rs

Lines 91 to 98 in 1e3c551

	let output = self
	.client
	.call(&self.identifier, input)
	.instrument_await(self.span.clone())
	.await
	.context(UdfSnafu {
	ident: self.identifier.as_str(),
	})?;

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• All checks passed in ./risedev check (or alias, ./risedev c)

Documentation

• My PR contains user-facing changes.

Click here for Documentation

Types of user-facing changes

Please keep the types that apply to your changes, and remove the others.

• Installation and deployment
• Connector (sources & sinks)
• SQL commands, functions, and operators
• RisingWave cluster configuration changes
• Other (please specify in the release note below)

Release note

[TennyZhuang]

Suggested change

	}
	}

[github-actions]

This PR has been open for 60 days with no activity. Could you please update the status? Feel free to ping a reviewer if you are waiting for review.

[BugenZhao]

Superseded by #11443 (comment) 🤡