gtg team mailing list archive

[Bryce Harrington <bryce@xxxxxxxxxxxxxxxxxxx>]

On Wed, May 19, 2010 at 01:43:05AM -0000, Luca Invernizzi wrote:
> Signals are executed when "there is time for them", without specific
> limits.
> 
> Now, when we issue the signal task-deleted, we should do a series of things (updating tags in the tag pane, removing the task and its children from the main view...).
> A number of times we need to access information about the task that has been removed. Example: we need to check if the tag that we are updating in the tags pane should be shown or not (are there still tasks tagged with that?)
> 
> This causes a series of problems, among which the drag and drop "phantom
> tasks" (tasks that are shown twice), or crashes upon deletion of tasks
> because the signal arrived too late and we cannot get the list of tags
> that need to be updated.
> 
> How to solve this?instead of passing the tid along with the signal, I think we should pass a copy of the whole task.
> I understand there are a series of things that need to be well thought out also with this approach and, since it's late and tomorrow is GTG Regression day, i'll regress to bed.

Another thought would be to add a Trash Stack; when a delete action
occurs, instead of outright deleting the task, it's moved to the Trash
Stack and a set of flags assigned for the various jobs that have to be
completed.  Signal handlers can then reference the task by tid and get
the data they need as they do their stuff.

A reaper process periodically reviews the structure and frees objects
who have all their job flags unchecked.

The Trash Stack would not be persisted across program restarts, so care
will need taken that no valid data references items in it.  IOW, make
sure to drop all references to the tid in data structures before putting
it in the Trash.

(This is a pretty crude garbage collection system, there may well be
better pythonic garbage collection systems out there.)

A fringe benefit of this is that an undo/undelete system could be hooked
into it without too much hassle.

-- 
sometimes task is removed before task-deleted signal handler is executed
https://bugs.launchpad.net/bugs/582620
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Status in Getting Things GNOME!: Confirmed

Bug description:
Signals are executed when "there is time for them", without specific limits.

Now, when we issue the signal task-deleted, we should do a series of things (updating tags in the tag pane, removing the task and its children from the main view...).
A number of times we need to access information about the task that has been removed. Example: we need to check if the tag that we are updating in the tags pane should be shown or not (are there still tasks tagged with that?)

This causes a series of problems, among which the drag and drop "phantom tasks" (tasks that are shown twice), or crashes upon deletion of tasks because the signal arrived too late and we cannot get the list of tags that need to be updated.

How to solve this?instead of passing the tid along with the signal, I think we should pass a copy of the whole task.
I understand there are a series of things that need to be well thought out also with this approach and, since it's late and tomorrow is GTG Regression day, i'll regress to bed.