Enhance suggestion logic for nested nullable objects

src/util/references.util.ts

@@ -271,9 +271,11 @@ const extractObjectProperties = (
     results.push({ path: currentPath, type });
   }
 
-  // Recursively traverse into object properties
-  if (isRealObjectType(type)) {
-    const properties = type.getProperties();
+  // Recursively traverse into object properties. Traversal also runs on the
+  // non-nullable type: a nullable object in the chain (e.g. `{bla?: TEXT} | null`)
+  // is a union whose getProperties() is empty, which would cut off all nested paths.
+  if (isRealObjectType(nonNullableType)) {
+    const properties = nonNullableType.getProperties();
     if (properties && properties.length > 0) {
       properties.forEach((property) => {
         const propType = checker.getTypeOfSymbolAtLocation(property, property.valueDeclaration!);

test/schema/schema.test.ts

@@ -825,4 +825,78 @@ describe("Schema", () => {
         ).toBe(true);
     });
 
+    it('offers a nested nullable object property as a ReferenceValue path suggestion for a plain TEXT parameter', () => {
+        // Node 1: custom::text::nested_nullable_object(): {test?: {bla?: TEXT | null} | null}
+        //   — no parameters, returns an object whose `test` property is an optional,
+        //   nullable object which itself holds an optional, nullable `bla` property.
+        // Node 2: std::text::split(value: TEXT, delimiter: TEXT): LIST<TEXT>
+        //
+        // The `value` parameter is declared as plain TEXT (string). Node 1's `test.bla`
+        // property has type string | null | undefined behind a nullable `test` object.
+        // Strict assignability would reject it, but the editor must still offer node 1's
+        // `test.bla` property as a ReferenceValue suggestion with referencePath
+        // [{path: "test"}, {path: "bla"}]: the nullish parts along the reference chain
+        // should be ignored for suggestion scoping.
+        const NESTED_NULLABLE_OBJECT_FN: FunctionDefinition = {
+            id: "gid://sagittarius/FunctionDefinition/9003",
+            identifier: "custom::text::nested_nullable_object",
+            signature: "(): {test?: {bla?: TEXT | null} | null}",
+        };
+
+        const flow: Flow = {
+            id: "gid://sagittarius/Flow/1",
+            startingNodeId: "gid://sagittarius/NodeFunction/1",
+            signature: "(): void",
+            nodes: {
+                nodes: [
+                    {
+                        id: "gid://sagittarius/NodeFunction/1",
+                        functionDefinition: {identifier: "custom::text::nested_nullable_object"},
+                        nextNodeId: "gid://sagittarius/NodeFunction/2",
+                        parameters: {
+                            nodes: [],
+                        },
+                    },
+                    {
+                        id: "gid://sagittarius/NodeFunction/2",
+                        functionDefinition: {identifier: "std::text::split"},
+                        parameters: {
+                            nodes: [
+                                {value: null},
+                                {value: {__typename: "LiteralValue", value: ","}},
+                            ],
+                        },
+                    },
+                ],
+            },
+        };
+
+        const [valueSchema] = getSignatureSchema(
+            flow,
+            DATA_TYPES,
+            [...FUNCTION_SIGNATURES, NESTED_NULLABLE_OBJECT_FN],
+            "gid://sagittarius/NodeFunction/2",
+        );
+
+        // value: TEXT → free-form text input.
+        expect(valueSchema.schema.input).toBe("text");
+
+        // Node 1's `test.bla` property is TEXT | null | undefined nested inside the
+        // nullable `test` object; stripping the nullish parts leaves TEXT, which is
+        // assignable to the TEXT parameter → node 1 must be offered with
+        // referencePath [{path: "test"}, {path: "bla"}].
+        const suggestions = (valueSchema.schema.suggestions ?? []) as any[];
+        expect(
+            suggestions.some(
+                (s) =>
+                    s.__typename === "ReferenceValue" &&
+                    s.nodeFunctionId === "gid://sagittarius/NodeFunction/1" &&
+                    Array.isArray(s.referencePath) &&
+                    s.referencePath.length === 2 &&
+                    s.referencePath[0].path === "test" &&
+                    s.referencePath[1].path === "bla",
+            ),
+        ).toBe(true);
+    });
+
 })