Fix 500 when sorting the default project board

[lng2020]

fix #29853
The problem is that checkProjectBoardChangePermission didn't check if the project board id == 0, which is the default project board.
BTW, I think the code about this default project board trick is a little redundant. It required every function to check whether the project board id == 0. I will clean it up afterward.

[delvh]

Can't we extract this into one func getContextBoard(ctx context, projectID int64) (project_model.Board, error)?

[lng2020]

I will clean it up afterward

That's what I mean in the PR description. I rather keep this PR focus on the fix. What do you think?

[silverwind]

Found this interesting comment:

gitea/templates/projects/view.tmpl

Line 168 in 095fdd6

<div class="ui cards {{if and $canWriteProject (ne .ID 0)}}{{/* ID 0 is default column which cannot be moved */}}tw-cursor-grab{{end}}" data-url="{{$.Link}}/{{.ID}}" data-project="{{$.Project.ID}}" data-board="{{.ID}}" id="board_{{.ID}}">

So it seems column 0 was at least initially never meant to be moved. I do agree we should allow it.

[silverwind]

It seems that the default column can indeed not be dragged itself, but another column can be dragged into its place, so the restriction is kind of pointless currently.

I think we should unrestrict column entirely either in this PR or a followup, removing the JS restriction that currently forbids the default column from being dragged.

[denyskon]

@silverwind The default column doesn't really exist, it's dynamically generated if there are no columns in a project. See #29874

[lng2020]

I think we should unrestrict column entirely either in this PR or a followup, removing the JS restriction that currently forbids the default column from being dragged.

The backend uses the sorting field to indicate the column location. As denyskon explained above, the backend didn't store the uncategorized column, so even if users are allowed to drag the uncategorized column, the uncategorized column will still be in the leftmost as long as the page refreshes.
This PR only fixes the 500 error. It won't resolve the problem that the changing uncategorized column position won't have any effect.

[silverwind]

@silverwind The default column doesn't really exist, it's dynamically generated if there are no columns in a project. See #29874

I still don't get it. Why is that board different from others and why can't it be sortable?

[lng2020]

@silverwind

gitea/routers/web/repo/projects.go

Lines 633 to 648 in 16e3600

	if ctx.ParamsInt64(":boardID") == 0 {
	board = &project_model.Board{
	ID: 0,
	ProjectID: project.ID,
	Title: ctx.Locale.TrString("repo.projects.type.uncategorized"),
	}
	} else {
	board, err = project_model.GetBoard(ctx, ctx.ParamsInt64(":boardID"))
	if err != nil {
	if project_model.IsErrProjectBoardNotExist(err) {
	ctx.NotFound("ProjectBoardNotExist", nil)
	} else {
	ctx.ServerError("GetProjectBoard", err)
	}
	return
	}

the DB didn't store the column. The backend checks it first and returns a mock one. Therefore, the sorting field, which is used for sorting, always defaults to value 0.
If we want to sort this column, we need to redesign the backend logic.

[silverwind]

So if we can't make it sortable on backend, we should just prevent dropping anything in place of the default column, should be possible in the JS.

Long term, it should be made sortable, just like it is on GitHub.

[lng2020]

should be possible in the JS.

The JS solution could replace this PR because no more requests about boardID=0 can be made so the backend can skip this check. Would you like to take over?

Long term, it should be made sortable, just like it is on GitHub.

After #29874, when projects are created, the default board can be treated like a normal board. The Uncategorized column, which is a pseudo-board with boardID=0, appears only when the default board is intentionally deleted. This Uncategorized column can not be sorted. Do you think the Uncategorized column should be sortable too?

[denyskon]

Well what we could do in #29874 is adding a migration to create the new default column retroactively, then disallow for a project to have less than one board (the last one cannot be deleted). Then we could get rid of board 0 completely.

[silverwind]

I think we should actually follow GitHub and make it possible to have multiple default columns, GitHub seems to have various template and the first one has thee columns "Todo", "In Progress", "Done". I think that'd be good set of default columns.

[denyskon]

That's another point, we already have project templates. Currently however we're taking about default columns for issues added to a project, which is currently either set manually or generated dynamically when the backend notices that the project doesn't have a default column. The proposal is to just add one if the project is empty and not to allow deleting all columns, then we would not have the need for dynamically generating this non-editable pseudo-column.

[silverwind]

should be possible in the JS.

The JS solution could replace this PR because no more requests about boardID=0 can be made so the backend can skip this check. Would you like to take over?

#29892 does that, making this PR obsolete I guess.

[denyskon]

Closing in favor of the proper fix in #29874 removing boardID 0 completely