Add $before and $after params to RETURN clauses (#2665)

lib/src/doc/lives.rs

@@ -172,10 +172,8 @@ impl<'a> Document<'a> {
 		if opt.check_perms(stm.into()) {
 			// Get the table
 			let tb = self.tb(opt, txn).await?;
-			// Get the permission clause
-			let perms = &tb.permissions.select;
 			// Process the table permissions
-			match perms {
+			match &tb.permissions.select {
 				Permission::None => return Err(Error::Ignore),
 				Permission::Full => return Ok(()),
 				Permission::Specific(e) => {

lib/src/doc/pluck.rs

@@ -26,13 +26,25 @@ impl<'a> Document<'a> {
 				Output::None => Err(Error::Ignore),
 				Output::Null => Ok(Value::Null),
 				Output::Diff => {
+					// Output a DIFF of any changes applied to the document
 					Ok(self.initial.doc.diff(self.current.doc.as_ref(), Idiom::default()).into())
 				}
-				Output::After => self.current.doc.compute(ctx, opt, txn, Some(&self.current)).await,
+				Output::After => {
+					// Output the full document after all changes were applied
+					self.current.doc.compute(ctx, opt, txn, Some(&self.current)).await
+				}
 				Output::Before => {
+					// Output the full document before any changes were applied
 					self.initial.doc.compute(ctx, opt, txn, Some(&self.initial)).await
 				}
-				Output::Fields(v) => v.compute(ctx, opt, txn, Some(&self.current), false).await,
+				Output::Fields(v) => {
+					// Configure the context
+					let mut ctx = Context::new(ctx);
+					ctx.add_value("after", self.current.doc.as_ref());
+					ctx.add_value("before", self.initial.doc.as_ref());
+					// Output the specified fields
+					v.compute(&ctx, opt, txn, Some(&self.current), false).await
+				}
 			},
 			None => match stm {
 				Statement::Live(s) => match s.expr.len() {

lib/tests/update.rs

@@ -206,6 +206,81 @@ async fn update_complex_with_input() -> Result<(), Error> {
 	Ok(())
 }
 
+#[tokio::test]
+async fn update_with_return_clause() -> Result<(), Error> {
+	let sql = "
+		CREATE person:test SET age = 18, name = 'John';
+		UPDATE person:test SET age = 25 RETURN VALUE $before;
+		UPDATE person:test SET age = 30 RETURN VALUE { old_age: $before.age, new_age: $after.age };
+		UPDATE person:test SET age = 35 RETURN age, name;
+		DELETE person:test RETURN VALUE $before;
+	";
+	let dbs = new_ds().await?;
+	let ses = Session::owner().with_ns("test").with_db("test");
+	let res = &mut dbs.execute(sql, &ses, None).await?;
+	assert_eq!(res.len(), 5);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				age: 18,
+				id: person:test,
+				name: 'John'
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				age: 18,
+				id: person:test,
+				name: 'John'
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				new_age: 30,
+				old_age: 25
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				age: 35,
+				name: 'John'
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				age: 35,
+				id: person:test,
+				name: 'John'
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	Ok(())
+}
+
 //
 // Permissions
 //