fix emergent behavior support in legacy relationships support

Author: runspired

Diff for: packages/model/src/-private/legacy-relationships-support.ts

@@ -189,14 +189,13 @@ export class LegacySupport {
       if (relatedIdentifier === null) {
         return null;
       } else {
-        const toReturn = store._instanceCache.getRecord(relatedIdentifier);
         assert(
           `You looked up the '${key}' relationship on a '${identifier.type}' with id ${
             identifier.id || 'null'
           } but some of the associated records were not loaded. Either make sure they are all loaded together with the parent record, or specify that the relationship is async (\`belongsTo(<type>, { async: true, inverse: <inverse> })\`)`,
-          toReturn === null || store._instanceCache.recordIsLoaded(relatedIdentifier, true)
+          store._instanceCache.recordIsLoaded(relatedIdentifier, true)
         );
-        return toReturn;
+        return store._instanceCache.getRecord(relatedIdentifier);
       }
     }
   }
@@ -523,7 +522,7 @@ export class LegacySupport {
     // in order to prevent infinite re-render if the request
     // fails.
     if (this._pending[key]) {
-      return this._pending[key]!;
+      return this._pending[key];
     }
 
     const identifier = resource.data ? resource.data : null;
@@ -563,7 +562,7 @@ export class LegacySupport {
         .finally(() => {
           this._pending[key] = undefined;
         });
-      return this._pending[key]!;
+      return this._pending[key];
     }
 
     const preferLocalCache = hasReceivedData && allInverseRecordsAreLoaded && !isEmpty;
@@ -599,7 +598,7 @@ export class LegacySupport {
         .finally(() => {
           this._pending[key] = undefined;
         });
-      return this._pending[key]!;
+      return this._pending[key];
     }
 
     // we were explicitly told we have no data and no links.