Fix tmp file being deleted after the request plus some cleanup and improved erroring for this situation

CHANGELOG

@@ -19,6 +19,7 @@ v 8.9.1
   - Fix 404 when accessing pipelines as guest user on public projects
   - Fix mobile Safari bug where horizontal nav arrows would flicker on scroll
   - Fix in auto merge when pipeline is nil
+  - Fix GitLab import project deleting imported file straight after being uploaded
 
 v 8.9.0
   - Fix builds API response not including commit data

app/controllers/import/gitlab_projects_controller.rb

@@ -12,9 +12,13 @@ class Import::GitlabProjectsController < Import::BaseController
       return redirect_back_or_default(options: { alert: "You need to upload a GitLab project export archive." })
     end
 
+    imported_file = params[:file].path + "-import"
+
+    FileUtils.copy_entry(params[:file].path, imported_file)
+
     @project = Gitlab::ImportExport::ProjectCreator.new(project_params[:namespace_id],
                                                         current_user,
-                                                        File.expand_path(project_params[:file].path),
+                                                        File.expand_path(imported_file),
                                                         project_params[:path]).execute
 
     if @project.saved?

lib/gitlab/import_export/file_importer.rb

@@ -23,7 +23,11 @@ module Gitlab
       private
 
       def decompress_archive
-        untar_zxf(archive: @archive_file, dir: @shared.export_path)
+        result = untar_zxf(archive: @archive_file, dir: @shared.export_path)
+
+        raise Projects::ImportService::Error.new("Unable to decompress #{@archive_file} into #{@shared.export_path}") unless result
+
+        true
       end
     end
   end

lib/gitlab/import_export/importer.rb

@@ -10,17 +10,22 @@ module Gitlab
       end
 
       def execute
-        Gitlab::ImportExport::FileImporter.import(archive_file: @archive_file,
-                                                  shared: @shared)
-        if check_version! && [project_tree, repo_restorer, wiki_restorer, uploads_restorer].all?(&:restore)
+        if import_file && check_version! && [project_tree, repo_restorer, wiki_restorer, uploads_restorer].all?(&:restore)
           project_tree.restored_project
         else
           raise Projects::ImportService::Error.new(@shared.errors.join(', '))
         end
+
+        remove_import_file
       end
 
       private
 
+      def import_file
+        Gitlab::ImportExport::FileImporter.import(archive_file: @archive_file,
+                                                  shared: @shared)
+      end
+
       def check_version!
         Gitlab::ImportExport::VersionChecker.check!(shared: @shared)
       end
@@ -59,6 +64,10 @@ module Gitlab
       def wiki_repo_path
         File.join(@shared.export_path, 'project.wiki.bundle')
       end
+
+      def remove_import_file
+        FileUtils.rm_rf(@archive_file)
+      end
     end
   end
 end