fix(federation): remove redundant typename for inline fragments

When adding `__typename` field for abstract types, we need to check for inline fragment type condition and not the parent selection set. If we have an inline fragment without type condition and it is pointing to and abstract type, then the required `__typename` field should have already been added to its parent field.

apollo-federation/src/operation/mod.rs

@@ -895,7 +895,19 @@ impl Selection {
     }
 
     fn sub_selection_type_position(&self) -> Option<CompositeTypeDefinitionPosition> {
-        Some(self.selection_set()?.type_position.clone())
+        match self {
+            Selection::Field(field_selection) => field_selection
+                .selection_set
+                .as_ref()
+                .map(|s| s.type_position.clone()),
+            Selection::FragmentSpread(fragment_selection) => {
+                Some(fragment_selection.spread.type_condition_position.clone())
+            }
+            Selection::InlineFragment(inline_fragment_selection) => inline_fragment_selection
+                .inline_fragment
+                .type_condition_position
+                .clone(),
+        }
     }
 
     pub(crate) fn conditions(&self) -> Result<Conditions, FederationError> {

apollo-federation/tests/query_plan/build_query_plan_tests.rs

@@ -914,3 +914,43 @@ fn test_merging_fetches_do_not_create_cycle_in_fetch_dependency_graph() {
     "###
     );
 }
+
+#[test]
+fn redundant_typename_for_inline_fragments_without_type_condition() {
+    let planner = planner!(
+        Subgraph1: r#"
+          type Query {
+            products: [Product]
+          }
+          interface Product {
+            name: String
+          }
+        "#,
+    );
+    assert_plan!(
+        &planner,
+        r#"
+          {
+            products {
+              ... @skip(if: false) {
+                name
+              }
+            }
+          }
+        "#,
+        @r###"
+        QueryPlan {
+          Fetch(service: "Subgraph1") {
+            {
+              products {
+                __typename
+                ... @skip(if: false) {
+                  name
+                }
+              }
+            }
+          },
+        }
+        "###
+    );
+}

apollo-federation/tests/query_plan/supergraphs/redundant_typename_for_inline_fragments_without_type_condition.graphql

@@ -0,0 +1,53 @@
+# Composed from subgraphs with hash: d267b3f18f7736e1a3e39a951696c318d1f46a34
+schema
+  @link(url: "https://specs.apollo.dev/link/v1.0")
+  @link(url: "https://specs.apollo.dev/join/v0.3", for: EXECUTION)
+{
+  query: Query
+}
+
+directive @join__enumValue(graph: join__Graph!) repeatable on ENUM_VALUE
+
+directive @join__field(graph: join__Graph, requires: join__FieldSet, provides: join__FieldSet, type: String, external: Boolean, override: String, usedOverridden: Boolean) repeatable on FIELD_DEFINITION | INPUT_FIELD_DEFINITION
+
+directive @join__graph(name: String!, url: String!) on ENUM_VALUE
+
+directive @join__implements(graph: join__Graph!, interface: String!) repeatable on OBJECT | INTERFACE
+
+directive @join__type(graph: join__Graph!, key: join__FieldSet, extension: Boolean! = false, resolvable: Boolean! = true, isInterfaceObject: Boolean! = false) repeatable on OBJECT | INTERFACE | UNION | ENUM | INPUT_OBJECT | SCALAR
+
+directive @join__unionMember(graph: join__Graph!, member: String!) repeatable on UNION
+
+directive @link(url: String, as: String, for: link__Purpose, import: [link__Import]) repeatable on SCHEMA
+
+scalar join__FieldSet
+
+enum join__Graph {
+  SUBGRAPH1 @join__graph(name: "Subgraph1", url: "none")
+}
+
+scalar link__Import
+
+enum link__Purpose {
+  """
+  `SECURITY` features provide metadata necessary to securely resolve fields.
+  """
+  SECURITY
+
+  """
+  `EXECUTION` features provide metadata necessary for operation execution.
+  """
+  EXECUTION
+}
+
+interface Product
+  @join__type(graph: SUBGRAPH1)
+{
+  name: String
+}
+
+type Query
+  @join__type(graph: SUBGRAPH1)
+{
+  products: [Product]
+}