🐛 Fixed importer duplicate detection for posts

closes #8717

- this is now required, because we run import queries sequentiell
- this code protects two cases:
  - you have duplicate slugs in the JSON file (the first get's inserted, the second get's ignored)
  - you have an existing slug in the database and you try to import the same slug, get's ignored

core/server/data/importer/importers/data/index.js

@@ -42,6 +42,7 @@ DataImporter = {
         if (importOptions && importOptions.importPersistUser) {
             modelOptions.importPersistUser = importOptions.importPersistUser;
         }
+
         this.init(importData);
 
         return models.Base.transaction(function (transacting) {

core/server/models/base/index.js

@@ -774,6 +774,12 @@ ghostBookshelf.Model = ghostBookshelf.Model.extend({
             if (!slug) {
                 slug = baseName;
             }
+
+            // CASE: no slug generation on import, see https://github.com/TryGhost/Ghost/issues/8717
+            if (options.importing) {
+                return slug;
+            }
+
             // Test for duplicate slugs.
             return checkIfSlugExists(slug);
         });

core/test/integration/data/importer/importers/data_spec.js

@@ -394,6 +394,8 @@ describe('Import', function () {
                 exportData = exported;
                 return dataImporter.doImport(exportData);
             }).then(function (importedData) {
+                importedData.data.posts.length.should.eql(1);
+
                 importedData.problems.length.should.eql(3);
                 importedData.problems[0].message.should.eql('Entry was not imported and ignored. Detected duplicated entry.');
                 importedData.problems[0].help.should.eql('Tag');