[BUGFIX release] Reference.reload should not cause sync-relationship assertion

addon/-legacy-private/system/relationships/state/belongs-to.js

@@ -225,7 +225,13 @@ export default class BelongsToRelationship extends Relationship {
       });
   }
 
-  getData() {
+  /*
+    While the `shouldForceReload` flag will also be true when `isForcedReload` is true,
+    `isForcedReload` is only `true` for an initial `getData` call during a forced reload.
+    Other calls must conform to the typical expectations, for instance, sync relationships
+    expect that their data is already loaded.
+   */
+  getData(isForcedReload = false) {
     //TODO(Igor) flushCanonical here once our syncing is not stupid
     let record = this.inverseInternalModel ? this.inverseInternalModel.getRecord() : null;
 
@@ -264,7 +270,7 @@ export default class BelongsToRelationship extends Relationship {
           "' with id " +
           this.internalModel.id +
           ' 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 (`DS.belongsTo({ async: true })`)',
-        record === null || !record.get('isEmpty')
+        record === null || !record.get('isEmpty') || isForcedReload
       );
       return record;
     }

addon/-legacy-private/system/relationships/state/has-many.js

@@ -344,7 +344,7 @@ export default class ManyRelationship extends Relationship {
       });
   }
 
-  getData() {
+  getData(isForcedReload = false) {
     //TODO(Igor) sync server here, once our syncing is not stupid
     let manyArray = this.manyArray;
 
@@ -379,7 +379,7 @@ export default class ManyRelationship extends Relationship {
         }' with id ${
           this.internalModel.id
         } 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 (\`DS.hasMany({ async: true })\`)`,
-        this.allInverseRecordsAreLoaded
+        this.allInverseRecordsAreLoaded || isForcedReload
       );
 
       return manyArray;

addon/-legacy-private/system/relationships/state/relationship.js

@@ -554,7 +554,7 @@ export default class Relationship {
 
     this.setHasFailedLoadAttempt(false);
     this.setShouldForceReload(true);
-    this.getData();
+    this.getData(true);
 
     return this._promiseProxy;
   }

tests/acceptance/relationships/belongs-to-test.js

@@ -27,7 +27,7 @@ class TestAdapter extends JSONAPIAdapter {
     this._payloads = arr;
   }
 
-  shouldBackgroundReload() {
+  shouldBackgroundReloadRecord() {
     return false;
   }
 

tests/acceptance/relationships/has-many-test.js

@@ -31,7 +31,7 @@ class TestAdapter extends JSONAPIAdapter {
     this._payloads = arr;
   }
 
-  shouldBackgroundReload() {
+  shouldBackgroundReloadRecord() {
     return false;
   }
 

tests/integration/records/create-record-test.js

@@ -133,7 +133,7 @@ module('Store.createRecord() coverage', function(hooks) {
     this.owner.register(
       'adapter:application',
       JSONAPIAdapter.extend({
-        shouldBackgroundReload() {
+        shouldBackgroundReloadRecord() {
           return false;
         },
         findRecord() {