Fix $value being NONE for DELETE events (#3869)

core/src/doc/event.rs

@@ -34,18 +34,23 @@ impl<'a> Document<'a> {
 			} else {
 				Value::from("UPDATE")
 			};
+			// Depending on type of event, how do we populate the document
+			let doc = match stm.is_delete() {
+				true => &self.initial,
+				false => &self.current,
+			};
 			// Configure the context
 			let mut ctx = Context::new(ctx);
 			ctx.add_value("event", met);
-			ctx.add_value("value", self.current.doc.deref());
+			ctx.add_value("value", doc.doc.deref());
 			ctx.add_value("after", self.current.doc.deref());
 			ctx.add_value("before", self.initial.doc.deref());
 			// Process conditional clause
-			let val = ev.when.compute(&ctx, opt, txn, Some(&self.current)).await?;
+			let val = ev.when.compute(&ctx, opt, txn, Some(doc)).await?;
 			// Execute event if value is truthy
 			if val.is_truthy() {
 				for v in ev.then.iter() {
-					v.compute(&ctx, opt, txn, Some(&self.current)).await?;
+					v.compute(&ctx, opt, txn, Some(doc)).await?;
 				}
 			}
 		}

lib/tests/define.rs

@@ -434,6 +434,64 @@ async fn define_statement_event_when_event() -> Result<(), Error> {
 	Ok(())
 }
 
+#[tokio::test]
+async fn define_statement_event_check_doc_always_populated() -> Result<(), Error> {
+	let sql = "
+		DEFINE EVENT test ON test WHEN true THEN {
+			LET $doc = $this;
+			CREATE type::thing('log', $event) SET this = $doc, value = $value, before = $before, after = $after;
+		};
+		CREATE test:1 SET num = 1;
+		UPDATE test:1 set num = 2;
+		DELETE test:1;
+		SELECT * FROM log;
+	";
+	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;
+	assert!(tmp.is_ok());
+	//
+	let tmp = res.remove(0).result;
+	assert!(tmp.is_ok());
+	//
+	let tmp = res.remove(0).result;
+	assert!(tmp.is_ok());
+	//
+	let tmp = res.remove(0).result;
+	assert!(tmp.is_ok());
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		r#"[
+			{
+					after: { id: test:1, num: 1 },
+					id: log:CREATE,
+					this: { id: test:1, num: 1 },
+					value: { id: test:1, num: 1 }
+			},
+			{
+					before: { id: test:1, num: 2 },
+					id: log:DELETE,
+					this: { id: test:1, num: 2 },
+					value: { id: test:1, num: 2 }
+			},
+			{
+					after: { id: test:1, num: 2 },
+					before: { id: test:1, num: 1 },
+					id: log:UPDATE,
+					this: { id: test:1, num: 2 },
+					value: { id: test:1, num: 2 }
+			}
+	]"#,
+	);
+	assert_eq!(tmp, val);
+	//
+	Ok(())
+}
+
 #[tokio::test]
 async fn define_statement_event_when_logic() -> Result<(), Error> {
 	let sql = "