Fix ConvexObject::filter_system_fields (#25873)

The previous implementation of ConvexObject::filter_system_fields modified `fields` but not `size` (or `nesting`) while it can change, which causes equality comparisons to fail.

This commit also adds a test which fails with the previous implementation but passes with the new one.

GitOrigin-RevId: abcd1d985efc047225013ad3eca7f590ec275db8

Author: Nicolapps

crates/value/src/object.rs

@@ -167,15 +167,13 @@ impl ConvexObject {
     }
 
     pub fn filter_system_fields(self) -> Self {
-        Self {
-            size: self.size,
-            nesting: self.nesting,
-            fields: self
-                .fields
-                .into_iter()
-                .filter(|(k, _)| !k.is_system())
-                .collect(),
-        }
+        let filtered_fields: BTreeMap<_, _> = self
+            .fields
+            .into_iter()
+            .filter(|(k, _)| !k.is_system())
+            .collect();
+        Self::try_from(filtered_fields)
+            .expect("Filtering an object should always produce a smaller, thus valid object")
     }
 }
 

crates/value/src/tests.rs

@@ -166,3 +166,18 @@ fn test_object_keys() -> anyhow::Result<()> {
         .contains("Field name $id starts with '$', which is reserved"));
     Ok(())
 }
+
+#[test]
+fn test_filter_system_fields() {
+    assert_eq!(
+        assert_obj!(
+            "_id" => "j571sbvz5zj1ps44j9f433pf1n6s7egs",
+            "_creationTime" => 1715895391903.0,
+            "name" => "Nicolas",
+        )
+        .filter_system_fields(),
+        assert_obj!(
+            "name" => "Nicolas",
+        )
+    )
+}