fix(project): correctly migrate old project view filters

This fixes a bug where old filters where not converted to the new json format correctly, leading to issues when trying to decode the raw filter string as json.
It is unclear whether that old migration had a bug or was not executed at all.

This change adds a new migration to fix all filters in views still stuck in the old filter string format.

Resolves https://github.com/go-vikunja/vikunja/issues/420

pkg/migration/20241118123644.go

@@ -68,7 +68,9 @@ func init() {
 					},
 				}
 
-				_, err = tx.Where("id = ?", view.ID).Update(newView)
+				_, err = tx.Where("id = ?", view.ID).
+					Cols("filter").
+					Update(newView)
 				if err != nil {
 					return
 				}

pkg/migration/20250323212553.go

@@ -0,0 +1,59 @@
+// Vikunja is a to-do list application to facilitate your life.
+// Copyright 2018-present Vikunja and contributors. All rights reserved.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public Licensee as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public Licensee for more details.
+//
+// You should have received a copy of the GNU Affero General Public Licensee
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package migration
+
+import (
+	"src.techknowlogick.com/xormigrate"
+	"xorm.io/xorm"
+)
+
+func init() {
+	migrations = append(migrations, &xormigrate.Migration{
+		ID:          "20250323212553",
+		Description: "",
+		Migrate: func(tx *xorm.Engine) (err error) {
+			oldViews := []*projectViews20241118123644{}
+
+			err = tx.Where("filter not like '{%' AND filter is not null AND filter != ''").Find(&oldViews)
+			if err != nil {
+				return
+			}
+
+			for _, view := range oldViews {
+				newView := &projectViews20241118123644New{
+					ID: view.ID,
+					Filter: &taskCollection20241118123644{
+						Filter: view.Filter,
+					},
+				}
+
+				_, err = tx.Where("id = ?", view.ID).
+					Cols("filter").
+					Update(newView)
+				if err != nil {
+					return
+				}
+			}
+
+			return
+		},
+
+		Rollback: func(tx *xorm.Engine) error {
+			return nil
+		},
+	})
+}