Add a failing test triggering the bug when we don't update all the splitnodes

Author: irevoire

src/tests/assets/v0_6/large.mdb

@@ -9,9 +9,9 @@ use crate::upgrade::from_0_6_to_current;
 use crate::{Database, Reader};
 
 #[test]
-fn upgrade_v0_6_to_v0_7() {
+fn simple_upgrade_v0_6_to_v0_7() {
     let dir = tempfile::tempdir().unwrap();
-    std::fs::copy("src/tests/assets/v0_6/data.mdb", dir.path().join("data.mdb")).unwrap();
+    std::fs::copy("src/tests/assets/v0_6/smol.mdb", dir.path().join("data.mdb")).unwrap();
     let env =
         unsafe { EnvOpenOptions::new().map_size(200 * 1024 * 1024).open(dir.path()) }.unwrap();
     let rtxn = env.read_txn().unwrap();
@@ -92,3 +92,47 @@ fn upgrade_v0_6_to_v0_7() {
     Item 5: Leaf(Leaf { header: NodeHeaderEuclidean { bias: 0.0 }, vector: [5.0000, 0.0000] })
     "#);
 }
+
+
+// Same test as above but with a larger database. See its original snapshot here: https://github.com/meilisearch/arroy/blob/f52bf0560f5ceef27946bf0522730649be46ccdd/src/tests/snapshots/arroy__tests__writer__write_and_update_lot_of_random_points-2.snap
+#[test]
+fn large_upgrade_v0_6_to_v0_7() {
+    let dir = tempfile::tempdir().unwrap();
+    std::fs::copy("src/tests/assets/v0_6/large.mdb", dir.path().join("data.mdb")).unwrap();
+    let env =
+        unsafe { EnvOpenOptions::new().map_size(200 * 1024 * 1024).open(dir.path()) }.unwrap();
+    let rtxn = env.read_txn().unwrap();
+    let database: Database<Euclidean> = env.open_database(&rtxn, None).unwrap().unwrap();
+
+    // First step is to know if we can still read into the database before the upgrade
+    let reader = Reader::open(&rtxn, 0, database).unwrap();
+    // The version is wrong but that's ok because the nodes format didn't change between v0.4 and v0.6 included.
+    // This bug has been fixed in v0.7.
+    insta::assert_snapshot!(reader.version(), @"v0.4.0");
+    insta::assert_snapshot!(reader.n_items(), @"100");
+    insta::assert_snapshot!(reader.n_trees(), @"10");
+    insta::assert_snapshot!(reader.dimensions(), @"30");
+    insta::assert_snapshot!(format!("{:?}", reader.item_ids()), @"RoaringBitmap<100 values between 0 and 99>");
+    insta::assert_snapshot!(format!("{:?}", reader.stats(&rtxn).unwrap()), @"Stats { leaf: 100, tree_stats: [TreeStats { depth: 4, dummy_normals: 0, split_nodes: 4, descendants: 5 }, TreeStats { depth: 5, dummy_normals: 0, split_nodes: 5, descendants: 6 }, TreeStats { depth: 4, dummy_normals: 0, split_nodes: 4, descendants: 5 }, TreeStats { depth: 7, dummy_normals: 0, split_nodes: 6, descendants: 7 }, TreeStats { depth: 5, dummy_normals: 0, split_nodes: 5, descendants: 6 }, TreeStats { depth: 5, dummy_normals: 0, split_nodes: 6, descendants: 7 }, TreeStats { depth: 4, dummy_normals: 0, split_nodes: 4, descendants: 5 }, TreeStats { depth: 6, dummy_normals: 0, split_nodes: 6, descendants: 7 }, TreeStats { depth: 5, dummy_normals: 0, split_nodes: 4, descendants: 5 }, TreeStats { depth: 6, dummy_normals: 0, split_nodes: 5, descendants: 6 }] }");
+    insta::assert_snapshot!(format!("{:?}", reader.item_vector(&rtxn, 0).unwrap()), @"Some([0.59189945, 0.9953131, 0.7271174, 0.7734485, 0.5760655, 0.8882299, 0.84973, 0.08173108, 0.39887708, 0.33842397, 0.16736221, 0.13506532, 0.7610012, 0.50516164, 0.51428705, 0.7101963, 0.44652337, 0.7144127, 0.31324244, 0.43315363, 0.98117304, 0.21394211, 0.8465342, 0.27935255, 0.70608264, 0.44866508, 0.9707988, 0.6317311, 0.94693947, 0.17849642])");
+    insta::assert_snapshot!(format!("{:?}", reader.item_vector(&rtxn, 25).unwrap()), @"Some([0.011625171, 0.53228873, 0.39399207, 0.13821805, 0.19865465, 0.7286784, 0.40262043, 0.14423728, 0.59565574, 0.03397578, 0.54211503, 0.80171144, 0.88514394, 0.5250775, 0.2614928, 0.4367664, 0.94518125, 0.05161941, 0.7546513, 0.5079431, 0.72314125, 0.47682863, 0.36076427, 0.3593862, 0.99203247, 0.5132183, 0.9997714, 0.8521869, 0.58587575, 0.5980581])");
+
+    let nns = reader
+        .nns(3)
+        .search_k(NonZeroUsize::new(100).unwrap())
+        .by_vector(&rtxn, &[0.0; 30])
+        .unwrap();
+    insta::assert_snapshot!(NnsRes(Some(nns)), @r"
+    id(92): distance(2.4881108)
+    id(24): distance(2.5068686)
+    id(78): distance(2.5809734)
+    ");
+
+    let mut wtxn = env.write_txn().unwrap();
+    from_0_6_to_current(&rtxn, database, &mut wtxn, database).unwrap();
+    wtxn.commit().unwrap();
+    drop(rtxn);
+
+    let handle = DatabaseHandle { env: env.clone(), database, tempdir: dir };
+    insta::assert_snapshot!(handle);
+}