hasura · hallettj · Jul 8, 2025 · Jul 8, 2025 · Jul 8, 2025 · hallettj
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,7 @@ This changelog documents the changes between release versions.
 ### Fixed
 
 - Filtering on field of related collection inside nested object that is not selected for output ([#171](https://github.com/hasura/ndc-mongodb/pull/171))
+- Ensure correct ordering of sort criteria in MongoDB query plan ([#172](https://github.com/hasura/ndc-mongodb/pull/172))
 
 ## [1.8.2] - 2025-06-13
 

diff --git a/crates/integration-tests/src/tests/filtering.rs b/crates/integration-tests/src/tests/filtering.rs
@@ -1,5 +1,6 @@
 use insta::assert_yaml_snapshot;
 use ndc_test_helpers::{binop, field, query, query_request, target, value, variable};
+use serde_json::json;
 
 use crate::{connector::Connector, graphql_query, run_connector_query};
 
@@ -105,3 +106,33 @@ async fn filters_by_uuid() -> anyhow::Result<()> {
     );
     Ok(())
 }
+
+#[tokio::test]
+async fn filters_by_multiple_criteria_using_variable() -> anyhow::Result<()> {
+    assert_yaml_snapshot!(
+        graphql_query(
+            r#"
+            query TestQuery($filter: [MoviesOrderBy!] = {}) {
+              movies(
+                order_by: $filter
+                where: { year: { _gt: 0 }, imdb: { rating: { _gt: 9 } } }
+                limit: 15
+              ) {
+                title
+                year
+                rated
+              }
+            }
+            "#
+        )
+        .variables(json!({
+            "filter": [
+                { "year": "Desc" },
+                { "rated": "Desc" },
+            ]
+        }))
+        .run()
+        .await?
+    );
+    Ok(())
+}
diff --git a/...ots/integration_tests__tests__filtering__filters_by_multiple_criteria_using_variable.snap b/...ots/integration_tests__tests__filtering__filters_by_multiple_criteria_using_variable.snap
@@ -0,0 +1,52 @@
+---
+source: crates/integration-tests/src/tests/filtering.rs
+expression: "graphql_query(r#\"\n            query TestQuery($filter: [MoviesOrderBy!] = {}) {\n              movies(\n                order_by: $filter\n                where: { year: { _gt: 0 }, imdb: { rating: { _gt: 9 } } }\n                limit: 15\n              ) {\n                title\n                year\n                rated\n              }\n            }\n            \"#).variables(json!({\n    \"filter\": [{ \"year\": \"Desc\" }, { \"rated\": \"Desc\" },]\n})).run().await?"
+---
+data:
+  movies:
+    - title: "A Brave Heart: The Lizzie Velasquez Story"
+      year: 2015
+      rated: PG-13
+    - title: The Real Miyagi
+      year: 2015
+      rated: ~
+    - title: Over the Garden Wall
+      year: 2014
+      rated: TV-PG
+    - title: Frozen Planet
+      year: 2011
+      rated: ~
+    - title: Human Planet
+      year: 2011
+      rated: ~
+    - title: Life
+      year: 2009
+      rated: PG
+    - title: Planet Earth
+      year: 2006
+      rated: TV-G
+    - title: Band of Brothers
+      year: 2001
+      rated: TV-MA
+    - title: The Blue Planet
+      year: 2001
+      rated: ~
+    - title: Pride and Prejudice
+      year: 1995
+      rated: ~
+    - title: Baseball
+      year: 1994
+      rated: TV-PG
+    - title: The Shawshank Redemption
+      year: 1994
+      rated: R
+    - title: The Shawshank Redemption
+      year: 1994
+      rated: R
+    - title: The Civil War
+      year: 1990
+      rated: ~
+    - title: The Civil War
+      year: 1990
+      rated: ~
+errors: ~
diff --git a/crates/mongodb-agent-common/src/query/make_sort.rs b/crates/mongodb-agent-common/src/query/make_sort.rs
@@ -1,5 +1,6 @@
 use std::{collections::BTreeMap, iter::once};
 
+use indexmap::IndexMap;
 use itertools::join;
 use mongodb::bson::bson;
 use mongodb_support::aggregate::{SortDocument, Stage};
@@ -42,7 +43,7 @@ pub fn make_sort_stages(order_by: &OrderBy) -> Result<Vec<Stage>> {
 fn make_sort(order_by: &OrderBy) -> Result<(SortDocument, RequiredAliases<'_>)> {
     let OrderBy { elements } = order_by;
 
-    let keys_directions_expressions: BTreeMap<String, (OrderDirection, Option<ColumnRef<'_>>)> =
+    let keys_directions_expressions: IndexMap<String, (OrderDirection, Option<ColumnRef<'_>>)> =
         elements
             .iter()
             .map(|obe| {
@@ -53,7 +54,7 @@ fn make_sort(order_by: &OrderBy) -> Result<(SortDocument, RequiredAliases<'_>)>
                 };
                 Ok((key, (obe.order_direction, required_alias)))
             })
-            .collect::<Result<BTreeMap<_, _>>>()?;
+            .collect::<Result<IndexMap<_, _>>>()?; // IndexMap preserves insertion order
 
     let sort_document = keys_directions_expressions
         .iter()
@@ -112,7 +113,7 @@ fn safe_alias(target: &OrderByTarget) -> Result<String> {
 
 #[cfg(test)]
 mod tests {
-    use mongodb::bson::doc;
+    use mongodb::bson::{self, doc};
     use mongodb_support::aggregate::SortDocument;
     use ndc_models::{FieldName, OrderDirection};
     use ndc_query_plan::OrderByElement;
@@ -175,4 +176,44 @@ mod tests {
         assert_eq!(actual, (expected_sort_doc, expected_aliases));
         Ok(())
     }
+
+    #[test]
+    fn serializes_sort_criteria_in_expected_order() -> anyhow::Result<()> {
+        let first_criteria = "year";
+        let second_criteria = "rated";
+        let order_by = OrderBy {
+            elements: vec![
+                OrderByElement {
+                    order_direction: OrderDirection::Desc,
+                    target: ndc_query_plan::OrderByTarget::Column {
+                        name: first_criteria.into(),
+                        field_path: None,
+                        path: Default::default(),
+                    },
+                },
+                OrderByElement {
+                    order_direction: OrderDirection::Desc,
+                    target: ndc_query_plan::OrderByTarget::Column {
+                        name: second_criteria.into(),
+                        field_path: None,
+                        path: Default::default(),
+                    },
+                },
+            ],
+        };
+        let (sort_doc, _) = make_sort(&order_by)?;
+        let serialized = bson::to_document(&sort_doc)?;
+        let mut sort_keys = serialized.keys();
+        assert_eq!(
+            sort_keys.next(),
+            Some(&first_criteria.to_string()),
+            "first sort criteria"
+        );
+        assert_eq!(
+            sort_keys.next(),
+            Some(&second_criteria.to_string()),
+            "second sort criteria"
+        );
+        Ok(())
+    }
 }