SUR-347 - Live Queries error when no change feed (#3772)

core/src/err/mod.rs

@@ -923,6 +923,10 @@ pub enum Error {
 	/// A node task has failed
 	#[error("A node task has failed: {0}")]
 	NodeAgent(&'static str),
+
+	/// An error related to live query occurred
+	#[error("Failed to process Live Query: {0}")]
+	LiveQueryError(LiveQueryCause),
 }
 
 impl From<Error> for String {
@@ -1037,3 +1041,14 @@ impl Serialize for Error {
 		serializer.serialize_str(self.to_string().as_str())
 	}
 }
+
+#[derive(Error, Debug)]
+#[non_exhaustive]
+pub enum LiveQueryCause {
+	#[doc(hidden)]
+	#[error("The Live Query must have a change feed for it it work")]
+	MissingChangeFeed,
+	#[doc(hidden)]
+	#[error("The Live Query must have a change feed that includes relative changes")]
+	ChangeFeedNoOriginal,
+}

core/src/sql/statements/live.rs

@@ -1,12 +1,13 @@
 use crate::ctx::Context;
 use crate::dbs::{Options, Transaction};
 use crate::doc::CursorDoc;
-use crate::err::Error;
+use crate::err::{Error, LiveQueryCause};
 use crate::fflags::FFLAGS;
 use crate::iam::Auth;
 use crate::kvs::lq_structs::{LqEntry, TrackedResult};
-use crate::sql::{Cond, Fetchs, Fields, Uuid, Value};
+use crate::sql::{Cond, Fetchs, Fields, Table, Uuid, Value};
 use derive::Store;
+use futures::lock::MutexGuard;
 use revision::revisioned;
 use serde::{Deserialize, Serialize};
 use std::fmt;
@@ -101,12 +102,15 @@ impl LiveStatement {
 			true => {
 				let mut run = txn.lock().await;
 				match stm.what.compute(ctx, opt, txn, doc).await? {
-					Value::Table(_tb) => {
+					Value::Table(tb) => {
+						let ns = opt.ns().to_string();
+						let db = opt.db().to_string();
+						self.validate_change_feed_valid(&mut run, &ns, &db, &tb).await?;
 						// Send the live query registration hook to the transaction pre-commit channel
 						run.pre_commit_register_async_event(TrackedResult::LiveQuery(LqEntry {
 							live_id: stm.id,
-							ns: opt.ns().to_string(),
-							db: opt.db().to_string(),
+							ns,
+							db,
 							stm,
 						}))?;
 					}
@@ -143,6 +147,31 @@ impl LiveStatement {
 		}
 	}
 
+	async fn validate_change_feed_valid(
+		&self,
+		tx: &mut MutexGuard<'_, crate::kvs::Transaction>,
+		ns: &str,
+		db: &str,
+		tb: &Table,
+	) -> Result<(), Error> {
+		// Find the table definition
+		let tb_definition = tx.get_and_cache_tb(ns, db, tb).await.map_err(|e| match e {
+			Error::TbNotFound {
+				value: _tb,
+			} => Error::LiveQueryError(LiveQueryCause::MissingChangeFeed),
+			_ => e,
+		})?;
+		// check it has a change feed
+		let cf = tb_definition
+			.changefeed
+			.ok_or(Error::LiveQueryError(LiveQueryCause::MissingChangeFeed))?;
+		// check the change feed includes the original - required for differentiating between CREATE and UPDATE
+		if !cf.store_original {
+			return Err(Error::LiveQueryError(LiveQueryCause::ChangeFeedNoOriginal));
+		}
+		Ok(())
+	}
+
 	pub(crate) fn archive(mut self, node_id: Uuid) -> LiveStatement {
 		self.archived = Some(node_id);
 		self

lib/tests/live.rs

@@ -8,7 +8,29 @@ use surrealdb::fflags::FFLAGS;
 use surrealdb::sql::Value;
 
 #[tokio::test]
-async fn live_query_sends_registered_lq_details() -> Result<(), Error> {
+async fn live_query_fails_if_no_change_feed() -> Result<(), Error> {
+	if !FFLAGS.change_feed_live_queries.enabled() {
+		return Ok(());
+	}
+	let sql = "
+		LIVE SELECT * FROM lq_test_123;
+	";
+	let dbs = new_ds().await?;
+	let ses = Session::owner().with_ns("test").with_db("test").with_rt(true);
+	let res = &mut dbs.execute(sql, &ses, None).await?;
+	assert_eq!(res.len(), 1);
+	let res = res.remove(0).result;
+	assert!(res.is_err(), "{:?}", res);
+	let err = res.as_ref().err().unwrap();
+	assert_eq!(
+		format!("{}", err),
+		"Failed to process Live Query: The Live Query must have a change feed for it it work"
+	);
+	Ok(())
+}
+
+#[tokio::test]
+async fn live_query_fails_if_change_feed_missing_diff() -> Result<(), Error> {
 	if !FFLAGS.change_feed_live_queries.enabled() {
 		return Ok(());
 	}
@@ -20,13 +42,37 @@ async fn live_query_sends_registered_lq_details() -> Result<(), Error> {
 	let ses = Session::owner().with_ns("test").with_db("test").with_rt(true);
 	let res = &mut dbs.execute(sql, &ses, None).await?;
 	assert_eq!(res.len(), 2);
+	res.remove(0).result.unwrap();
+	let res = res.remove(0).result;
+	assert!(res.is_err(), "{:?}", res);
+	let err = res.as_ref().err().unwrap();
+	assert_eq!(
+		format!("{}", err),
+		"Failed to process Live Query: The Live Query must have a change feed that includes relative changes"
+	);
+	Ok(())
+}
+
+#[tokio::test]
+async fn live_query_sends_registered_lq_details() -> Result<(), Error> {
+	if !FFLAGS.change_feed_live_queries.enabled() {
+		return Ok(());
+	}
+	let sql = "
+		DEFINE TABLE lq_test_123 CHANGEFEED 10m INCLUDE ORIGINAL;
+		LIVE SELECT * FROM lq_test_123;
+	";
+	let dbs = new_ds().await?;
+	let ses = Session::owner().with_ns("test").with_db("test").with_rt(true);
+	let res = &mut dbs.execute(sql, &ses, None).await?;
+	assert_eq!(res.len(), 2);
 
 	// Define table didnt fail
 	let tmp = res.remove(0).result;
 	assert!(tmp.is_ok());
 
 	// Live query returned a valid uuid
-	let actual = res.remove(0).result?;
+	let actual = res.remove(0).result.unwrap();
 	let live_id = match actual {
 		Value::Uuid(live_id) => live_id,
 		_ => panic!("Expected a UUID"),