fix(gatsby): Fix potential issue in fragment cycles detection (#20953)

Author: vladar

packages/gatsby/src/query/query-compiler.js

@@ -431,7 +431,7 @@ const determineUsedFragmentsForDefinition = (
   definition,
   definitionsByName,
   fragmentsUsedByFragment,
-  visitedFragmentDefinitions = new Set()
+  visitedFragments = new Set()
 ) => {
   const { def, name, isFragment, filePath } = definition
   const cachedUsedFragments = fragmentsUsedByFragment.get(name)
@@ -444,11 +444,11 @@ const determineUsedFragmentsForDefinition = (
       [Kind.FRAGMENT_SPREAD]: node => {
         const name = node.name.value
         const fragmentDefinition = definitionsByName.get(name)
-        if (visitedFragmentDefinitions.has(fragmentDefinition)) {
-          return
-        }
-        visitedFragmentDefinitions.add(fragmentDefinition)
         if (fragmentDefinition) {
+          if (visitedFragments.has(name)) {
+            return
+          }
+          visitedFragments.add(name)
           usedFragments.add(name)
           const {
             usedFragments: usedFragmentsForFragment,
@@ -457,7 +457,7 @@ const determineUsedFragmentsForDefinition = (
             fragmentDefinition,
             definitionsByName,
             fragmentsUsedByFragment,
-            visitedFragmentDefinitions
+            visitedFragments
           )
           usedFragmentsForFragment.forEach(fragmentName =>
             usedFragments.add(fragmentName)