fix(kanban): don't prevent setting a different bucket as done bucket

Resolves vikunja/frontend#3373

pkg/models/kanban.go

@@ -293,10 +293,14 @@ func (b *Bucket) Update(s *xorm.Session, _ web.Auth) (err error) {
 	}
 
 	if doneBucket != nil && doneBucket.IsDoneBucket && b.IsDoneBucket && doneBucket.ID != b.ID {
-		return &ErrOnlyOneDoneBucketPerProject{
-			BucketID:     b.ID,
-			ProjectID:    b.ProjectID,
-			DoneBucketID: doneBucket.ID,
+		// When the current bucket will be the new done bucket, the old one should not be the done bucket anymore
+		doneBucket.IsDoneBucket = false
+		_, err = s.
+			Where("id = ?", doneBucket.ID).
+			Cols("is_done_bucket").
+			Update(doneBucket)
+		if err != nil {
+			return
 		}
 	}
 

pkg/models/kanban_test.go

@@ -217,7 +217,7 @@ func TestBucket_Update(t *testing.T) {
 
 		testAndAssertBucketUpdate(t, b, s)
 	})
-	t.Run("only one done bucket per project", func(t *testing.T) {
+	t.Run("old done bucket should be unset", func(t *testing.T) {
 		db.LoadAndAssertFixtures(t)
 		s := db.NewSession()
 		defer s.Close()
@@ -229,7 +229,16 @@ func TestBucket_Update(t *testing.T) {
 		}
 
 		err := b.Update(s, &user.User{ID: 1})
-		assert.Error(t, err)
-		assert.True(t, IsErrOnlyOneDoneBucketPerProject(err))
+		assert.NoError(t, err)
+		db.AssertExists(t, "buckets", map[string]interface{}{
+			"id":             1,
+			"project_id":     1,
+			"is_done_bucket": true,
+		}, false)
+		db.AssertExists(t, "buckets", map[string]interface{}{
+			"id":             3,
+			"project_id":     1,
+			"is_done_bucket": false,
+		}, false)
 	})
 }