Prevent Infinite Loop in OverlappingFieldsCanBeMergedRule

Author: nicolaslt

src/validation/__tests__/OverlappingFieldsCanBeMergedRule-test.ts

@@ -1021,6 +1021,17 @@ describe('Validate: Overlapping fields can be merged', () => {
     `);
   });
 
+  it('does not infinite loop on immediately recursive fragment mentionned in queries', () => {
+    expectValid(`
+      query myQuery {
+        todoRemove
+        ...fragA
+      }
+
+      fragment fragA on Query { ...fragA }
+    `);
+  });
+
   it('does not infinite loop on transitively recursive fragment', () => {
     expectValid(`
       fragment fragA on Human { name, ...fragB }

src/validation/rules/OverlappingFieldsCanBeMergedRule.ts

@@ -267,6 +267,10 @@ function collectConflictsBetweenFieldsAndFragment(
   // (E) Then collect any conflicts between the provided collection of fields
   // and any fragment names found in the given fragment.
   for (const referencedFragmentName of referencedFragmentNames) {
+    if (referencedFragmentName === fragmentName) {
+      continue;
+    }
+
     collectConflictsBetweenFieldsAndFragment(
       context,
       conflicts,