Store task errors following migrations and display them (#13246)

* Store task errors following migrations and display them

When migrate tasks fail store the error in the task table
and ensure that they show on the status page.

Fix #13242

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update web_src/js/index.js

* Hide the failed first

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

routers/user/task.go

@@ -0,0 +1,30 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package user
+
+import (
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/context"
+)
+
+// TaskStatus returns task's status
+func TaskStatus(ctx *context.Context) {
+	task, opts, err := models.GetMigratingTaskByID(ctx.ParamsInt64("task"), ctx.User.ID)
+	if err != nil {
+		ctx.JSON(500, map[string]interface{}{
+			"err": err,
+		})
+		return
+	}
+
+	ctx.JSON(200, map[string]interface{}{
+		"status":    task.Status,
+		"err":       task.Errors,
+		"repo-id":   task.RepoID,
+		"repo-name": opts.RepoName,
+		"start":     task.StartTime,
+		"end":       task.EndTime,
+	})
+}