FIX: fixed potential bug in info object that is passed to onTypeConfl… (

#3216)

* FIX: fixed potential bug in info object that is passed to onTypeConflict callback  and caused right and left to reference the same object.

* Added a test that checks if info object passed to the onTypeConflict callback contains right and left objects with properties that are not equal.

* Removed unnecessary async from onTypeConflict test

* Added a changeset

.changeset/curly-items-glow.md

@@ -0,0 +1,5 @@
+---
+'@graphql-tools/stitch': patch
+---
+
+Fixed issue with stitchSchemas function returning info object with left.subschema and right.subschema referencing the same object

packages/stitch/src/typeCandidates.ts

@@ -236,8 +236,8 @@ function onTypeConflictToCandidateSelector<TContext = Record<string, any>>(
           transformedSubschema: prev.transformedSubschema,
         },
         right: {
-          subschema: prev.subschema,
-          transformedSubschema: prev.transformedSubschema,
+          subschema: next.subschema,
+          transformedSubschema: next.transformedSubschema,
         },
       });
       if (prev.type === type) {

packages/stitch/tests/alternateStitchSchemas.test.ts

@@ -1930,6 +1930,18 @@ describe('onTypeConflict', () => {
     const result2 = await graphql(stitchedSchema, '{ test1 { fieldC } }');
     expect(result2.data).toBeUndefined();
   });
+
+  test('returns info.left and info.right properties that are not equal', () => {
+    stitchSchemas({
+      subschemas: [schema1, schema2],
+      mergeTypes: false,
+      onTypeConflict: (left, _right, info) => {
+        expect(info?.right.subschema !== info?.left.subschema).toBe(true);
+        expect(info?.right.transformedSubschema !== info?.left.transformedSubschema).toBe(true);
+        return left;
+      }
+    });
+  });
 });
 
 describe('basic type merging', () => {