fix(gatsby-source-drupal): handle edge case with deleting nodes (#33143)

* fix(gatsby-source-drupal): handle edge case with deleting nodes

In this case, when trying to deleting a node's references nodes, we were crashing if the referenced
node had already been deleted.

* also cleanup referencedNodesLookup

packages/gatsby-source-drupal/src/__tests__/fixtures/1593545806.json

@@ -1,11 +1,21 @@
 {
   "timestamp": 1593545807,
   "entities": [
+    {
+      "action": "delete",
+      "id": "article-71",
+      "type": "node--article"
+    },
     {
       "action": "delete",
       "id": "file-4",
       "type": "file--file"
     },
+    {
+      "action": "delete",
+      "id": "does-not-exist",
+      "type": "file--file"
+    },
     {
       "jsonapi": {
         "version": "1.0",

packages/gatsby-source-drupal/src/__tests__/fixtures/article.json

@@ -73,6 +73,38 @@
           "data": null
         }
       }
+    },
+    {
+      "type": "node--article",
+      "id": "article-71",
+      "attributes": {
+        "id": 223,
+        "uuid": "article-71",
+        "title": "Article #71",
+        "body": "Proin pulvinar hendrerit magna nec maximus. Donec rhoncus libero ac nisi porttitor pulvinar. Quisque semper ultricies nulla sit amet vestibulum. Ut vel libero erat. Ut ultrices eleifend scelerisque. Nam non massa sit amet magna molestie tempus vel non neque. Praesent ac est congue, euismod mi ut, tristique mi. Etiam dapibus feugiat lectus, vel condimentum nisl maximus et. Praesent et placerat magna. Sed nec risus non ipsum venenatis placerat. Vestibulum vitae felis eget nunc mattis congue. Morbi volutpat odio purus. Donec placerat massa sed neque molestie, sed finibus nibh scelerisque. In faucibus ante tortor, in efficitur lectus feugiat vitae. Aliquam sodales mollis consectetur."
+      },
+      "relationships": {
+        "field_secondary_image": {
+          "data": [
+            {
+              "type": "file--file",
+              "id": "file-4"
+            }
+          ]
+        },
+        "field_secondary_multiple_image": {
+          "data": [
+            {
+              "type": "file--file",
+              "id": "file-3"
+            },
+            {
+              "type": "file--file",
+              "id": "file-4"
+            }
+          ]
+        }
+      }
     }
   ],
   "links": {

packages/gatsby-source-drupal/src/utils.js

@@ -136,50 +136,58 @@ const handleDeletedNode = async ({
     return deletedNode
   }
 
-  // Remove the deleted node from backRefsNamesLookup
+  // Remove the deleted node from backRefsNamesLookup and referencedNodesLookup
   backRefsNamesLookup.delete(deletedNode)
+  referencedNodesLookup.delete(deletedNode)
 
   // Remove relationships from other nodes and re-create them.
   Object.keys(deletedNode.relationships).forEach(key => {
     let ids = deletedNode.relationships[key]
     ids = [].concat(ids)
     ids.forEach(id => {
       const node = getNode(id)
-      let referencedNodes = referencedNodesLookup.get(node)
-      if (referencedNodes?.includes(deletedNode.id)) {
-        // Loop over relationships and cleanup references.
-        Object.entries(node.relationships).forEach(([key, value]) => {
-          // If a string ref matches, delete it.
-          if (_.isString(value) && value === deletedNode.id) {
-            delete node.relationships[key]
-          }
-
-          // If it's an array, filter, then check if the array is empty and then delete
-          // if so
-          if (_.isArray(value)) {
-            value = value.filter(v => v !== deletedNode.id)
-
-            if (value.length === 0) {
+
+      // The referenced node might have already been deleted.
+      if (node) {
+        let referencedNodes = referencedNodesLookup.get(node)
+        if (referencedNodes?.includes(deletedNode.id)) {
+          // Loop over relationships and cleanup references.
+          Object.entries(node.relationships).forEach(([key, value]) => {
+            // If a string ref matches, delete it.
+            if (_.isString(value) && value === deletedNode.id) {
               delete node.relationships[key]
-            } else {
-              node.relationships[key] = value
             }
-          }
-        })
 
-        // Remove deleted node from array of referencedNodes
-        referencedNodes = referencedNodes.filter(nId => nId !== deletedNode.id)
-        referencedNodesLookup.set(node, referencedNodes)
-      }
-      // Recreate the referenced node with its now cleaned-up relationships.
-      if (node.internal.owner) {
-        delete node.internal.owner
-      }
-      if (node.fields) {
-        delete node.fields
+            // If it's an array, filter, then check if the array is empty and then delete
+            // if so
+            if (_.isArray(value)) {
+              value = value.filter(v => v !== deletedNode.id)
+
+              if (value.length === 0) {
+                delete node.relationships[key]
+              } else {
+                node.relationships[key] = value
+              }
+            }
+          })
+
+          // Remove deleted node from array of referencedNodes
+          referencedNodes = referencedNodes.filter(
+            nId => nId !== deletedNode.id
+          )
+          referencedNodesLookup.set(node, referencedNodes)
+        }
+
+        // Recreate the referenced node with its now cleaned-up relationships.
+        if (node.internal.owner) {
+          delete node.internal.owner
+        }
+        if (node.fields) {
+          delete node.fields
+        }
+        node.internal.contentDigest = createContentDigest(node)
+        actions.createNode(node)
       }
-      node.internal.contentDigest = createContentDigest(node)
-      actions.createNode(node)
     })
   })