From 36d83ebccf867c380c47b8ad7dfd3e4ebe55072c Mon Sep 17 00:00:00 2001
From: Micha de Vries <micha@devrie.sh>
Date: Mon, 5 Aug 2024 19:06:54 +0200
Subject: [PATCH] Remove faulty flatten (#4463)

---
 core/src/sql/value/get.rs | 18 +++++++---
 lib/tests/select.rs       | 72 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 4 deletions(-)

diff --git a/core/src/sql/value/get.rs b/core/src/sql/value/get.rs
index 519bf94a..b57a2c2d 100644
--- a/core/src/sql/value/get.rs
+++ b/core/src/sql/value/get.rs
@@ -250,10 +250,20 @@ impl Value {
 											.run(|stk| stm.compute(stk, ctx, opt, None))
 											.await?
 											.all();
-										stk.run(|stk| v.get(stk, ctx, opt, None, path.next()))
-											.await?
-											.flatten()
-											.ok()
+										let res = stk
+											.run(|stk| v.get(stk, ctx, opt, None, path.next()))
+											.await?;
+										// We only want to flatten the results if the next part
+										// is a graph part. Reason being that if we flatten fields,
+										// the results of those fields (which could be arrays) will
+										// be merged into each other. So [1, 2, 3], [4, 5, 6] would
+										// become [1, 2, 3, 4, 5, 6]. This slice access won't panic
+										// as we have already checked the length of the path.
+										Ok(if let Part::Graph(_) = path[1] {
+											res.flatten()
+										} else {
+											res
+										})
 									}
 								}
 							}
diff --git a/lib/tests/select.rs b/lib/tests/select.rs
index 3848c89c..395f0e6f 100644
--- a/lib/tests/select.rs
+++ b/lib/tests/select.rs
@@ -1224,3 +1224,75 @@ async fn select_destructure() -> Result<(), Error> {
 	//
 	Ok(())
 }
+
+#[tokio::test]
+async fn select_field_from_graph_no_flattening() -> Result<(), Error> {
+	let sql = "
+        CREATE a:1, a:2;
+
+        RELATE a:1->b:1->a:2 SET list = [1, 2, 3];
+        RELATE a:1->b:2->a:2 SET list = [4, 5, 6];
+
+        SELECT VALUE ->b.list FROM a:1;
+	";
+	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(), 4);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+    		{ id: a:1 },
+    		{ id: a:2 }
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				id: b:1,
+				in: a:1,
+				out: a:2,
+				list: [1, 2, 3]
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+			{
+				id: b:2,
+				in: a:1,
+				out: a:2,
+				list: [4, 5, 6]
+			}
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	let tmp = res.remove(0).result?;
+	let val = Value::parse(
+		"[
+		    [
+    			[
+    			    1,
+                    2,
+                    3
+                ],
+                [
+                    4,
+                    5,
+                    6
+                ]
+			]
+		]",
+	);
+	assert_eq!(tmp, val);
+	//
+	Ok(())
+}